Heat made by resistance, that's what it means. The power of heating will be P=R*I*I and I=V/r, so more resistance only gives you more power if you keep current flow but current gets lower with more resistance, so to keep current you need to give more tension (V). If resistance is 0 you get no heat, it's just current flowing, it's the resistance that makes the heat. Imagine you are trying to make fire with two sticks. If you don't press the sticks to each other (make some resistance) you can move the sticks (current) and there will be no heat. If you press the sticks to each other you will have some heat. If you press more (more resistance) you only have more heat if you keep the movement but because you are making the same effort (same V) your movement will be slower (less I) and you will have less heat.
Thank you for this. The stick example is great. So if you increased effort (V) to maintain the same speed of sticks you would create more heat as well.
More resistance under the same pressure will get u less power (wattage ) so less heat. If u give it more pressure (voltage) , to get the same current as before , that heat will much greate
@@Arvidje if you give more voltage and get the same current, than your resistence is higher, since I = V/ R. If P = R x I² and R is bigger than the power is bigger.
Bro its drawing less because the resistance increased. You need to now double the volts to overcome the resistance needed for it to glow hotter , which in this case 20 amps. Classic electronics
So many people have no idea how electricity actually works. They're the same kind of people who think that if something normally uses a 1 amp wall adaptor and you hook it up to a 2 amp adaptor, you'll "fry" it. They don't seem to understand that a load with a fixed resistance will only draw a certain amount of current, and it makes no difference how much current the power supply is *capable* of providing. As long as you have the right voltage, you could hook it up to a 20 amp transformer and it wouldn't make any difference.
The company I worked for believes resistance and friction are the same thing. I opened my mouth of five years experience and asked wouldn’t less resistance generate more heat? And I got laughed off the table. They believe that resistance increases heat because the amperage is attempting to overcome the resistance. I never said they were wrong it just didn’t make sense to me and of course none of them can just say I’m flat out wrong they just have to try to make me feel stupid and condescend me. Then I see videos like this and was like wow I might have had a slight clue. And i learned to lead with fact and not arrogance and question even your mentors
Resistance can mean several different things. In this case, resistance means the cohesive resistance of the metal. Different metals have different resistance. Given current, some explode, some produce heat instead. Respectfully, comparing this type of resistance to a car going up hill isn’t valid. It’s not resistance of the load, but resistance of the material that creates the heat. When you add more material, you decrease the heat.
Pretty good point you've made and very fundamental. You don't even have to account for any reactance in a purely resistive circuit with an AC power source. Even the glowing versus not glowing is a great indication. I'm happy to see you're still making videos.
i always thought that high resistance causes more heat. but seems like thats not the case. I learned this from watching this video, so thanks :) im grateful
Hello Gray, Could tell me what type of material are the heating elements sitting on? (thise white pieces). I am trying to make a large oven with several elements for a custom project but I do not know where to hang the elements on. Thanks.
More resistance under the same pressure will get u less power (wattage ) so less heat. If u give it more pressure (voltage) , to get the same current as before , that heat will much greater.
So I have a heater that puts out 1300 watts on LOW and 1500 watts on high...I'd like to make it (on low ) run down to 500 Watts if possible or close to it. How would I do that? I have a tiny generator that can't do it but almost. Is it possible to lower the watts on LOW?
Point well made there GFM When is a Hot Water heater required if the water is already hot? Water Heaters heat water Ni chrome wire offers more resistance than copper so it creates heat. Perhaps they should have called it something different but it does what it says. Them electrons get real busy when they hit resistance. In fairness power distribution wiring should then be called Low electrical resistance non heating conductive pathways? It's all good, I guess it is a matter of semantics?
Another good video GFM...... Hey I have a Goodman 2 ton.......heat pump.......outdoor ambient of 95....suction pressure 60 ....suction line temperature is 84 degree...........liquid line pressure is 225......liquid line temperature is 95 What do you think the problem is..???? would it be the TXV ????
grayfurnaceman I think I found the problem........Im sure its not the charge.......so I started looking for restrictions.....just like you said......the air handler is in the attic.....it has 3/4 and 3/8 running up the wall into the attic.....but outside next to the condenser ...lol ...some idiot has stuck a short piece of 5/16 into the 3/8 between the wall and the condenser..........and in the attic ....somewhere between where it comes out of the wall and the air handler....lol......the idiots have stuck another section of 5/16 in between there and the air handler.....and about 2 or 4 feet from the air handler the idiot....changed it back to 3/8.............lol rofl......I told the home owner I would fix that Monday........GFM the system is running a 72 psi suction with a 228 head and the suction temp is 74......lol rofl.....I first thought it might be over charged with to much liquid.....because the home owner said that about once a year somebody has to put refrigerant in it....... Thank you for replying and helping me figure this out .....and keep making those video's
I want to put a hot plate element to halve the current on a microwave oven transformer. To stop it burning the secondary windings out as the transformer gets hot with in 1minute of operation. As a fan is not keeping it cool enough during operation secondary side is 2.1Kv and the primary is 250v a.c. As I use the transformer to clean spark plugs with high voltage and only needs about 5 seconds at 2.5Kv and the plugs are nice and clean afterwards and works better than a wire brush too.
You are misunderstanding the terms. Understandable, the terms make no sense. Increasing resistance reduces the production of heat. If the circuit has more resistance, less amperage will pass thru. Less amperage means less total power used by the circuit. Less power means less heat. GFM
For more efficiency I would recommend an invention. Using Ac induction with a coil (no contact) and combine it with Dc direct or indirect resistance heating by induction at one side and direct resistance heating at the other. AC and DC will create more heat together, I think by higher and opposite electromagnetic fields. It is not the same... When you put 10v Ac induction... And compare between 5v Ac and Dc, then you can conclude and realize if it is more efficient.
*I think you meant that the higher the resistance, the less power that is drawn giving you less heat. To output the same amount of heat with double the resistance, you will need twice the amount of power, voltage or current.
Its still resistance heating to me. Good video I just think its still resistance heating. It heats up because of resistance doesnt matter if its inverse due to ohms law.
The way you wired the resistors determine how much current is allowed to flow through them.... Parallel allows more current to flow than in series.. Which means you will have less resistance to current in parallel than in series then more power ( heat dessicated). By keeping the same current and adding more resistance then u can get more heat to do that follow P=RI`2
You were doing fine until that last sentence. Adding more resistance, when done in parallel, is simply adding another circuit, not more resistance. GFM
Great video! I don't know why so many people have it completely backwards. Ohm's Law states that Voltage/Resistance = Current. Therefore, at the same voltage, more resistance will cause LESS current to flow through the circuit, which means LESS heat. So many people have absolutely no idea how electricity actually works. It's like they think resistance is the same as friction or something.
agree! Mostly people confused is that more resistance will cause LESS current to flow through the circuit, which means LESS heat. But how about the conductor?? Conductor has low resistance will cause MORE current to flow through, why the conductor never heat?? haha..
Wow, you used numbers and a common means* to really do-it-yourself. Thanks sincerely. The other overwhelming do-it-yourselfers (Approx. 100 publications) leave one guessing or buy it from the store...connect to computer program etc...etc..(lengths, numbers, hookups they don't include).
Ohms law and not a myth. Equiv- series resistance add-up hence half current while equiv-parallel resistance is here is halved, hence 2xce the amperage.
Ohm's law is not the myth. The myth is the concept that "resistance" somehow equals more heat dissipated. The less resistance, the more heat dissipated. The opposite of the concept is true. It not about physical definition and more about the concept of "more resistance means more heat". GFM
Picture it like this: if you have a battery and you closed that circuit by connecting negative and positive wire together there will be a spark, that spark is caused by electron traveling at a rapid speed, if you hold that wire long enough, it will generate heat because of those electrons traveling at rapid speed, depending on the size of the wire and the voltage applied to it,it might break. We add a resistor (in this case your coil wire) then close the circuit (putting negative and positive together through the resistor) what in turn happens is that for the electrons to cross over from the live wire , they must first go through the resistor, the resistor like a free way toll gate, it restrict the amount of electrons that can go at a time, those electrons going through the resistor produce heat at that resistor while going through it (think of the resistor as a spark point when join negative a positive together)at certain a limited speed . When you connect resistors in series, it's like adding two toll gate in series(too much resistance will act like air) you end up creating "traffic" where U find like one car(electron) moving after five minutes, in our terms, the electrons no longer move at the same speed thus don't cause much heat cause when one electrons moves after five minutes, the generated heat caused by that resistor moving is cooled off by surrounding temperature during that five minutes break, but if you have five five million electrons moving at a resistor per second, there's little to no time for surrounding temperature to cool off heat generated by those racing electrons. You can also picture it as rubbing your hands when it's cold, if you rub fast you generate heat, you rub slow you don't generate heat and that's what resistors do, they control the rate of electrons moving in a circuit ( the rate your rub your hand in the example).
According to ohms law More resistance means less current if we're considering voltage to be constant. That means high resistance should have less current drawing capability. I don't think you get it!
The amount of heat dissipated is inversely related to the amount of resistance of the element. So less resistance, more heat dissipated. The only limit is the ability of the element to dissipate the heat without overheating. GFM
If you operate the heater at its rated voltage, you will get the maximum heat that the element can safely produce. Btw, electric elements are 100% efficient. GFM
grayfurnaceman ok, what if I'm in a situation where I need to find the right resistance for a value of voltage to get maximum heat instead of finding the right voltage for a value of resistance to get maximum heat? Let say the voltage is 12V, what the resistance has to be to maximize heat?
@@luongmaihunggia I know your question is old, but I'll just say that the first thing you would need to know is how much current can whatever device/material you're using carry before it gets TOO hot and burns or melts. Then divide the voltage by the current and that will tell you how much resistance you need. So let's say for example that you're using a wire or something which can carry 12 amps and you want to use 12 volts. 12 volts/12 amps=1 Ohm. So you will need 1 Ohm of resistance in the circuit to limit the current to the 12 amps that the wire can handle. You can either do that with the wire itself by having it long enough to have 1 Ohm of resistance, OR you can use another load in series with the wire to limit the current. If you're using some kind of experimental material you made yourself to generate heat, then you'll need to know how much current it can take before it burns, and how much resistance it has.
I thought resistance meant the iron element is higher resistance to the copper wire and the elements resistance causes an element to glow red. From that, if you made the element out of copper it would have less resistance to the incoming current and therefore produce less heat than a iron element of the same size. It seems they are defining the element as a simple resistor whereas you are defining a resistor as something in the wire, pre element, either a mechanical device or different wiring setup. I think they are saying iron is a poor conductor and copper is a great conductor, conductance being the opposite of resistance.
Resistance in electricity is different than other physical forms of resistance. If I place a box on a floor and then move the box, it will take more power to move the box than if I grease the bottom of the box. Electric resistance is pretty much the opposite. The iron has a higher resistance so it limits current flow. Current flow is power. If I used an iron element of the same length and size as a copper element, the copper element would produce more heat because there is a higher current flow. The end result would be that the copper element would melt due to its lower melting point than Iron and higher current flow. GFM
@@grayfurnaceman Good Argument with calculating the money spent on double the lenth of wire. But i must say what egg inc is on something. Let's say for instance you want to temper steel between 200-300c.. then you don't need as much heat. Then I will configure them in series. Because you are opening and closing the furnace all the time between heats you introduce oxygen to the elements. At a higher operating temp (not in series), they will oxidize faster and shorten the lifespan of the element. Now the controller regulates on toggling on and off, meaning if you put them in series they will heat up to let's say maybe 400. So the element will be on for longer to regulate but the element won't be stressed as much. Then the stress on the relay will be less as well. Depending on what you are heating the cycle quantities of the relay can get high. So basically you save stress on your relay(less current and less switching) as well on the resistive wire not oxidizing because of lower operating temperature. But I'm hearing what gfm is trying to explain to the uninformed. I'm just pointing out further technical stuff which the video wasn't about.
A good example of this, are the old-fashioned incandescent light bulbs: A 50 Watt lightbulb has double the resistance of a 100 Watt lightbulb. Sometimes you want just a 50 Watt lamp, and at other times the 100 Watt :)
The current is limited in the coil because incoming power is AC which causes inductive reactance. If the element were heated with DC current this wouldn't occur.
There is little inductance with those open coils. The I^2 * R has the more effect on heat. The current ( I ) was halved and the resistance ( R ) was doubled but the square of the current gives the greater change.
This type of load has virtually no inductive reactance. If DC power is used, the total power dissipated will be higher but the series connection will result in the same reduction in power dissipation. I will do a video on that. GFM
Joule heating is no different that BTUs per hour except in the numbers and time. The issue here is the assumption that increased resistance equals more heat. Even though the concept that increased resistance somehow increases work done, or heat released, it is not true. If electrical power is given a low resistance circuit, the power thru the circuit and thus heat released will increase over a high resistance circuit. We are working here with real world measurements and an understanding that increased resistance does not mean increased work done or heat released in the electrical circuit. GFM
Where do you get the idea that people assume increased resistance equals more heat? I've never heard that assumption. It's called resistance heat because without the resistance it would be called a short circuit.
I taught this subject for 9 years and that's the assumption that most of my students had. They equate it with driving a car up a hill. More resistance = more fuel used. GFM
Please read until the end. I am confused. I held the assumption that elements with higher resistance will allow for less energy flow and the energy lost through a voltage drop would be converted to heat. I helped to design a high voltage tesla coil bearing this assumption and what I predicted and calculated was accurate. I attributed the loss of heat in your experiment to the fact that the heat was distributed evenly across the elements and the reduced energy density caused them not to glow. The amps were insufficient to maintain voltage and it dropped, causing both elements to heat evenly. I pictured the heating as a bell curve, with a sweet spot which is determined by the amps. It is the distance between the actual resistance and the sweet spot which determines heat and you were closer with only one element. Doubling this increased the distance and caused for less energy density. I have held this in my mind for years and used it to logically predict how efficient heating elements would be with great success. The conclusions I made regarding the experiment were predictions based on assumptions. Hearing it explained this way confuses me and without mathematics to analyze the results, I may be completely wrong. I would like a deeper explanation over this if you find time. Thank you and keep up the good work
@@grayfurnaceman but you have to consider the material being used too. You've gone past the optimal resistance for this material, resulting in the drop in amps
You have shown that relationship between current and resistance, but it somewhat twists the relationship to heat/power you're trying to imply. A better experiment/presentation would be running the same amount of voltage through pieces of copper wire and nichrome wire, both with the same diameter, length, and turns. It will clearly demonstrate that increased resistance = increased heat. This also shows why in various situations heating elements are combined with things like ceramic and quarts
@@rocki_bb Your basic understanding of resistance, amperage flow and power used is flawed. I effectively did your experiment. Its the point of this video. the higher resistance wire consumed less amperage (energy) than the lower one. Ceramic is used in electric heaters, not as a conductor but as a heat radiant. GFM
Myth? you just added more surface area for the energy and reduced the resistance by allowing the current more time to flow. It is the backup of to much current that generates the heat. If you restrict the current input on your first example you would have gotten the same result as your second example. A rheostat is a variable resistor which is used to control current flow into the elements either tungsten or nichrome wire because of their high resistance to temperature and current flow. SO simply put the more current you try to cram down the wire the hotter it will get. Volume and pressure. "SLAPS FOREHEAD AND WALKS AWAY in dis belief!" :)
Unfortunately, you are completely wrong here. Electricity does not work that way. This is exactly the reason for this video. I know it seems that if I increase resistance, the energy to overcome the resistance will increase. Such as if I travel up hill in a vehicle, the resistance to my moving up increases and more energy is used. In electricity that does not happen. If I increase the resistance to flow, as I did when I added the 2d element I doubled the resistance to flow. That halves the current. If you rewatch the video it is obvious. Consider if I placed a short copper wire in an outlet. One end of the wire in one side of the plug, one end in the other. Very low resistance. That would, using your thinking, mean very little current would flow. The actual result is a "short", aptly named. The circuit protection would immediately open. That is because the current flow was very high. In the thousands of amps. Think about it. GFM
@@grayfurnaceman this is properly a stupid question... but i just have to ask... if the circuit in series draw less amps... where does that force go? if force is a constant... shouldnt that mean that if the circuit is applyed the same amount of force, the path whith most resistans, has a bigger change from moving energy (electrons moving) to heat energy (electrons stopping and turning in to heat)? im just curious...Loved the video btw... keep opp the good work!
The understanding of electrical energy is quite easily misunderstood. Resistance is like a valve on a water line. the water passing thru is the energy expended. High resistance is like the valve being opened just a small amount. If I increase the pressure (voltage), more will pass thru if the valve opening has not changed. Also, electrons do not change speed. Just the number of them passing is decreased when the valve is restricted. When the electron passes thru it effects the material it is passing thru. Something like a vehicle driving at a fixed speed thru air. The air is displaced by the vehicle and the air is heated as the vehicle passes. Not a perfect analogy, but pretty close.Hope this helps. GFM
So basically it seems 4 years ago everyone was dumb. Who told you power increase with resistance, it will increase or decrease depending on whether voltage source is independent or current source is! that is P(heat) = V²/R or P(heat) = I²R. And btw, it is called resistance heater because it's inductance is negligible and is kind of purely resistive load, otherwise manufacturer would have named it induction heater. Also ideally induction heater shouldn't feel warm to touch but it does, because it still has ESR to some extent. I wouldn't have commented on such a old video but the level of stupidity in comments section forces me to do so
Dude, you never increased the power when connecting the elements in series. You can't display a proper comparison unless you bring both circuits to the same temperature.
@@NoName-ly9xl The point of the demonstration is to show that increased resistance will reduce, rather than increase current flow in a circuit. It is a common myth that increased resistance will increase current flow. temperature is not part of the equation. GFM
Yeah, it is proportional to the resistance, so the power of heating goes up linearly as the resistance goes up. On the other hand, the power of heating increases exponentially as the current increases. So, when the heating elements are put in series, the resistance is doubled, but the current is cut in half. The net effect on the power of heating is that it's cut in half (0,5^2 * 2 = 0,5).
I don't think this guy has the slightest understanding of at least the 2 basic ohm's law formulas: V/R=A and VA=W and no understanding of series vs parallel circuits and formulas either.
The first part of your statement does no fit with the last part. How can resistance cause more heat if the resistance is increased you get less heat. GFM
The formula notwithstanding, you still move less current if you increase resistance. Perhaps instead of calling it resistance heat, maybe we should call it lack of resistance heat. GFM
No, well resistivity is inverse of conductivity. And reflects as a concept the inperfection of materials ability to ‘move’ electrons through it. It’s a bit like friction. Imagine a stream of electrons rushing through with some speed a bumping into uneaven surface, potholes and such. Each time they dissipate a little bit of heat. Ohms law illustrates this where the current is equal to potential divided by resistance. So in our analogy you would have charged potential e.g. kinetic energy and the flow through this pipe or surface would be dictated by how condusive is this surface or pipe to the flow of electrons. So the lost energy would change into heat. (ref. thermodynamics) Say wood would be so highly resistive that the electrons would not even flow ... but in these instances the circuit is not even closed for practical purposes and hence nothing happens...
@@stevenrachko8696 Do the numbers. Reduce the resistance and the amperage goes up. Your analogy of kinetic energy does not apply to electricity. It is not friction, thermodynamics does not apply here. Your wood analogy would mean extreme resistance would increase heat. It does not. GFM
well just double the voltage and you’ll get twice the heat... that is all there is to it. Alternatively you can just use a more resistive wire with same voltage (make it thinner or longer or use a different material). It is that simple and that analogy is used to illustrate the fundamental processes that cause this...
If a furnace repairman came to my house with this half true logic, I would not let him touch my furnace. He might be a good furnace tech, but his point is lost to those educated in ohms law.
No, you seem to be the one who is confused. Ohm's Law states that Voltage/Resistance=Current. So if you either lower the voltage or increase the resistance, there will be LESS current flow. In the video, he connected 2 heater elements in series, which doubled the resistance and therefore there was less current. So the heater elements didn't get as hot. His point was to show that a lot of people have a total misunderstanding about how electricity works and mistakenly think that "resistance means more heat" which is actually the exact opposite of reality.
Heat made by resistance, that's what it means. The power of heating will be P=R*I*I and I=V/r, so more resistance only gives you more power if you keep current flow but current gets lower with more resistance, so to keep current you need to give more tension (V). If resistance is 0 you get no heat, it's just current flowing, it's the resistance that makes the heat. Imagine you are trying to make fire with two sticks. If you don't press the sticks to each other (make some resistance) you can move the sticks (current) and there will be no heat. If you press the sticks to each other you will have some heat. If you press more (more resistance) you only have more heat if you keep the movement but because you are making the same effort (same V) your movement will be slower (less I) and you will have less heat.
Thank you for this. The stick example is great. So if you increased effort (V) to maintain the same speed of sticks you would create more heat as well.
Thank you for this wonderful explanation!
More resistance under the same pressure will get u less power (wattage ) so less heat. If u give it more pressure (voltage) , to get the same current as before , that heat will much greate
@@Arvidje if you give more voltage and get the same current, than your resistence is higher, since I = V/ R. If P = R x I² and R is bigger than the power is bigger.
Bro its drawing less because the resistance increased. You need to now double the volts to overcome the resistance needed for it to glow hotter , which in this case 20 amps. Classic electronics
spot on
GFM can you do a video explaining a few different examples of wiring in series and in parallel? Thanks
Twice the resistance EQUALS , lower current as shown , why would anyone think that lower power will give more heat, you need to parallel them , my god
So many people have no idea how electricity actually works. They're the same kind of people who think that if something normally uses a 1 amp wall adaptor and you hook it up to a 2 amp adaptor, you'll "fry" it. They don't seem to understand that a load with a fixed resistance will only draw a certain amount of current, and it makes no difference how much current the power supply is *capable* of providing. As long as you have the right voltage, you could hook it up to a 20 amp transformer and it wouldn't make any difference.
Exactly, and with his accent it's not so much necessary to explain. 🤔 It's just sad...
The company I worked for believes resistance and friction are the same thing. I opened my mouth of five years experience and asked wouldn’t less resistance generate more heat? And I got laughed off the table. They believe that resistance increases heat because the amperage is attempting to overcome the resistance. I never said they were wrong it just didn’t make sense to me and of course none of them can just say I’m flat out wrong they just have to try to make me feel stupid and condescend me. Then I see videos like this and was like wow I might have had a slight clue. And i learned to lead with fact and not arrogance and question even your mentors
Resistance can mean several different things. In this case, resistance means the cohesive resistance of the metal. Different metals have different resistance. Given current, some explode, some produce heat instead. Respectfully, comparing this type of resistance to a car going up hill isn’t valid. It’s not resistance of the load, but resistance of the material that creates the heat. When you add more material, you decrease the heat.
Hi, Is it possible to use an element of 1500w by breaking it into 300w. Is there any method by which it will work, wont balst?
Well, you aren't decreasing the heat, it's just dissipated over a larger area?
Pretty good point you've made and very fundamental. You don't even have to account for any reactance in a purely resistive circuit with an AC power source.
Even the glowing versus not glowing is a great indication.
I'm happy to see you're still making videos.
I am still here, making 3 a week.
GFM
Nicely explaination. this misunderstanding .
another great video.
Thanks for the support.
GFM
Hello GFM, How are the resistance coils configured in a domestic heater?
I have a number of videos on electric heat. Check my channel.
GFM
i always thought that high resistance causes more heat. but seems like thats not the case. I learned this from watching this video, so thanks :) im grateful
Welcome
GFM
Hello Gray,
Could tell me what type of material are the heating elements sitting on? (thise white pieces). I am trying to make a large oven with several elements for a custom project but I do not know where to hang the elements on.
Thanks.
ceramic
@@veronicamiller3073 Thanks
hopefully this is answered quickly.
so if I want to reduce the total heat generation, i would want a higher resistance? just making sure i understand
You got it.
GFM
great, thanks ...
More resistance under the same pressure will get u less power (wattage ) so less heat. If u give it more pressure (voltage) , to get the same current as before , that heat will much greater.
Thank youuuuuu Sir!! 😄
So I have a heater that puts out 1300 watts on LOW and 1500 watts on high...I'd like to make it (on low ) run down to 500 Watts if possible or close to it. How would I do that? I have a tiny generator that can't do it but almost. Is it possible to lower the watts on LOW?
The only way to reduce wattage is to wire 2 heaters in series.
GFM
Point well made there GFM
When is a Hot Water heater required if the water is already hot?
Water Heaters heat water
Ni chrome wire offers more resistance than copper so it creates heat. Perhaps they should have called it something different but it does what it says. Them electrons get real busy when they hit resistance.
In fairness power distribution wiring should then be called Low electrical resistance non heating conductive pathways?
It's all good, I guess it is a matter of semantics?
Out of curiosity- how many amps were being fed in? You mentioned voltage in but not amperage.
At 1:15 the meter is reading the amp draw.
GFM
Can i ask what material are the spring is made off ??
It is called nichrome.
GFM
Another good video GFM......
Hey I have a Goodman 2 ton.......heat pump.......outdoor ambient of 95....suction pressure 60 ....suction line temperature is 84 degree...........liquid line pressure is 225......liquid line temperature is 95
What do you think the problem is..???? would it be the TXV ????
Look for low charge or restriction.
GFM
grayfurnaceman I think I found the problem........Im sure its not the charge.......so I started looking for restrictions.....just like you said......the air handler is in the attic.....it has 3/4 and 3/8 running up the wall into the attic.....but outside next to the condenser ...lol ...some idiot has stuck a short piece of 5/16 into the 3/8 between the wall and the condenser..........and in the attic ....somewhere between where it comes out of the wall and the air handler....lol......the idiots have stuck another section of 5/16 in between there and the air handler.....and about 2 or 4 feet from the air handler the idiot....changed it back to 3/8.............lol rofl......I told the home owner I would fix that Monday........GFM the system is running a 72 psi suction with a 228 head and the suction temp is 74......lol rofl.....I first thought it might be over charged with to much liquid.....because the home owner said that about once a year somebody has to put refrigerant in it.......
Thank you for replying and helping me figure this out .....and keep making those video's
Welcome
GFM
What is the Resistance or AMP vs Heat graph ?
Heat is just 3.42 BTU per watt.
GFM
Spot on
I want to put a hot plate element to halve the current on a microwave oven transformer. To stop it burning the secondary windings out as the transformer gets hot with in 1minute of operation. As a fan is not keeping it cool enough during operation secondary side is 2.1Kv and the primary is 250v a.c. As I use the transformer to clean spark plugs with high voltage and only needs about 5 seconds at 2.5Kv and the plugs are nice and clean afterwards and works better than a wire brush too.
If U reduce the AMPS by 2 does the heat reduce by 2 ?
If amps are reduced and voltage stays the same, the heat will be reduced.
GFM
What would you call it? It is heating up do to resistance.
You are misunderstanding the terms. Understandable, the terms make no sense. Increasing resistance reduces the production of heat. If the circuit has more resistance, less amperage will pass thru. Less amperage means less total power used by the circuit. Less power means less heat.
GFM
Can you explain how a 3phase electric heater works.
They are fairly simple. However, not simple enough for a comment answer. Look for a video in the next couple of weeks.
GFM
For more efficiency I would recommend an invention. Using Ac induction with a coil (no contact) and combine it with Dc direct or indirect resistance heating by induction at one side and direct resistance heating at the other. AC and DC will create more heat together, I think by higher and opposite electromagnetic fields.
It is not the same... When you put 10v Ac induction... And compare between 5v Ac and Dc, then you can conclude and realize if it is more efficient.
*I think you meant that the higher the resistance, the less power that is drawn giving you less heat. To output the same amount of heat with double the resistance, you will need twice the amount of power, voltage or current.
Doesn't the additional coil create more resistence and therefore decrease current flow?
Yes, it does. that is the point of the video.
GFM
Its still resistance heating to me. Good video I just think its still resistance heating. It heats up because of resistance doesnt matter if its inverse due to ohms law.
The way you wired the resistors determine how much current is allowed to flow through them.... Parallel allows more current to flow than in series.. Which means you will have less resistance to current in parallel than in series then more power ( heat dessicated).
By keeping the same current and adding more resistance then u can get more heat to do that follow P=RI`2
You were doing fine until that last sentence.
Adding more resistance, when done in parallel, is simply adding another circuit, not more resistance.
GFM
Great video! I don't know why so many people have it completely backwards. Ohm's Law states that Voltage/Resistance = Current. Therefore, at the same voltage, more resistance will cause LESS current to flow through the circuit, which means LESS heat. So many people have absolutely no idea how electricity actually works. It's like they think resistance is the same as friction or something.
Agreed.
GFM
agree!
Mostly people confused is that more resistance will cause LESS current to flow through the circuit, which means LESS heat.
But how about the conductor??
Conductor has low resistance will cause MORE current to flow through, why the conductor never heat?? haha..
Resistance kind of is friction! If you think about it.
* common means: Mains from house, or battery that one can replace, easy nicrome theory. Again, thanks for some hands on for a change.
Wow, you used numbers and a common means* to really do-it-yourself. Thanks sincerely.
The other overwhelming do-it-yourselfers
(Approx. 100 publications) leave one guessing or buy it from the store...connect to computer program etc...etc..(lengths, numbers, hookups they don't include).
Hydronics please
Ohms law and not a myth. Equiv- series resistance add-up hence half current while equiv-parallel resistance is here is halved, hence 2xce the amperage.
Ohm's law is not the myth. The myth is the concept that "resistance" somehow equals more heat dissipated. The less resistance, the more heat dissipated. The opposite of the concept is true. It not about physical definition and more about the concept of "more resistance means more heat".
GFM
@@grayfurnaceman wrong - more resistance means less heat
Picture it like this: if you have a battery and you closed that circuit by connecting negative and positive wire together there will be a spark, that spark is caused by electron traveling at a rapid speed, if you hold that wire long enough, it will generate heat because of those electrons traveling at rapid speed, depending on the size of the wire and the voltage applied to it,it might break. We add a resistor (in this case your coil wire) then close the circuit (putting negative and positive together through the resistor) what in turn happens is that for the electrons to cross over from the live wire , they must first go through the resistor, the resistor like a free way toll gate, it restrict the amount of electrons that can go at a time, those electrons going through the resistor produce heat at that resistor while going through it (think of the resistor as a spark point when join negative a positive together)at certain a limited speed . When you connect resistors in series, it's like adding two toll gate in series(too much resistance will act like air) you end up creating "traffic" where U find like one car(electron) moving after five minutes, in our terms, the electrons no longer move at the same speed thus don't cause much heat cause when one electrons moves after five minutes, the generated heat caused by that resistor moving is cooled off by surrounding temperature during that five minutes break, but if you have five five million electrons moving at a resistor per second, there's little to no time for surrounding temperature to cool off heat generated by those racing electrons. You can also picture it as rubbing your hands when it's cold, if you rub fast you generate heat, you rub slow you don't generate heat and that's what resistors do, they control the rate of electrons moving in a circuit ( the rate your rub your hand in the example).
According to ohms law More resistance means less current if we're considering voltage to be constant. That means high resistance should have less current drawing capability. I don't think you get it!
Low resistance is still resistance ....we don't say high resistance electric heat lol
Im pretty sure its still resistance heat, just when you ad too much resistance it dosent heat as well, there is a sweet spot.
The amount of heat dissipated is inversely related to the amount of resistance of the element. So less resistance, more heat dissipated. The only limit is the ability of the element to dissipate the heat without overheating.
GFM
So HOW DO you get the maximum heat?
If you operate the heater at its rated voltage, you will get the maximum heat that the element can safely produce. Btw, electric elements are 100% efficient.
GFM
grayfurnaceman ok, what if I'm in a situation where I need to find the right resistance for a value of voltage to get maximum heat instead of finding the right voltage for a value of resistance to get maximum heat? Let say the voltage is 12V, what the resistance has to be to maximize heat?
Beats me. Take that one to an engineer.
GFM
@@luongmaihunggia I know your question is old, but I'll just say that the first thing you would need to know is how much current can whatever device/material you're using carry before it gets TOO hot and burns or melts. Then divide the voltage by the current and that will tell you how much resistance you need. So let's say for example that you're using a wire or something which can carry 12 amps and you want to use 12 volts. 12 volts/12 amps=1 Ohm. So you will need 1 Ohm of resistance in the circuit to limit the current to the 12 amps that the wire can handle. You can either do that with the wire itself by having it long enough to have 1 Ohm of resistance, OR you can use another load in series with the wire to limit the current.
If you're using some kind of experimental material you made yourself to generate heat, then you'll need to know how much current it can take before it burns, and how much resistance it has.
I thought resistance meant the iron element is higher resistance to the copper wire and the elements resistance causes an element to glow red. From that, if you made the element out of copper it would have less resistance to the incoming current and therefore produce less heat than a iron element of the same size. It seems they are defining the element as a simple resistor whereas you are defining a resistor as something in the wire, pre element, either a mechanical device or different wiring setup. I think they are saying iron is a poor conductor and copper is a great conductor, conductance being the opposite of resistance.
Resistance in electricity is different than other physical forms of resistance.
If I place a box on a floor and then move the box, it will take more power to move the box than if I grease the bottom of the box.
Electric resistance is pretty much the opposite. The iron has a higher resistance so it limits current flow. Current flow is power.
If I used an iron element of the same length and size as a copper element, the copper element would produce more heat because there is a higher current flow.
The end result would be that the copper element would melt due to its lower melting point than Iron and higher current flow.
GFM
Wouldn’t running in series be more cost effective and longer element life. Saying if your in a smaller in closure.
I am not sure how you would save money by using twice the length of element wire. Also, you will get half the heat.
GFM
@@grayfurnaceman Good Argument with calculating the money spent on double the lenth of wire. But i must say what egg inc is on something. Let's say for instance you want to temper steel between 200-300c.. then you don't need as much heat. Then I will configure them in series. Because you are opening and closing the furnace all the time between heats you introduce oxygen to the elements. At a higher operating temp (not in series), they will oxidize faster and shorten the lifespan of the element. Now the controller regulates on toggling on and off, meaning if you put them in series they will heat up to let's say maybe 400. So the element will be on for longer to regulate but the element won't be stressed as much. Then the stress on the relay will be less as well. Depending on what you are heating the cycle quantities of the relay can get high. So basically you save stress on your relay(less current and less switching) as well on the resistive wire not oxidizing because of lower operating temperature. But I'm hearing what gfm is trying to explain to the uninformed. I'm just pointing out further technical stuff which the video wasn't about.
A good example of this, are the old-fashioned incandescent light bulbs: A 50 Watt lightbulb has double the resistance of a 100 Watt lightbulb. Sometimes you want just a 50 Watt lamp, and at other times the 100 Watt :)
The current is limited in the coil because incoming power is AC which causes inductive reactance. If the element were heated with DC current this wouldn't occur.
There is little inductance with those open coils. The I^2 * R has the
more effect on heat. The current ( I ) was halved and the resistance
( R ) was doubled but the square of the current gives the greater
change.
This type of load has virtually no inductive reactance. If DC power is used, the total power dissipated will be higher but the series connection will result in the same reduction in power dissipation. I will do a video on that.
GFM
I always thought that term resistance was dumb and made no sense. Now I have the proof!!! 👍👍
Yeah, I wonder who came up with that one.
GFM
I think the alternative term for electric resistance heating is joule heating which might make more sense in this case
Joule heating is no different that BTUs per hour except in the numbers and time. The issue here is the assumption that increased resistance equals more heat. Even though the concept that increased resistance somehow increases work done, or heat released, it is not true. If electrical power is given a low resistance circuit, the power thru the circuit and thus heat released will increase over a high resistance circuit. We are working here with real world measurements and an understanding that increased resistance does not mean increased work done or heat released in the electrical circuit.
GFM
Where do you get the idea that people assume increased resistance equals more heat? I've never heard that assumption. It's called resistance heat because without the resistance it would be called a short circuit.
I taught this subject for 9 years and that's the assumption that most of my students had. They equate it with driving a car up a hill. More resistance = more fuel used.
GFM
I love all your other videos but honestly you should redo this one:(
What do you think should be changed?
GFM
+grayfurnaceman
measure the resistance before and after so we can plug in the numbers.
hvac&r for life!!!
Ouch this hurt to watch...
Please read until the end. I am confused. I held the assumption that elements with higher resistance will allow for less energy flow and the energy lost through a voltage drop would be converted to heat. I helped to design a high voltage tesla coil bearing this assumption and what I predicted and calculated was accurate. I attributed the loss of heat in your experiment to the fact that the heat was distributed evenly across the elements and the reduced energy density caused them not to glow. The amps were insufficient to maintain voltage and it dropped, causing both elements to heat evenly. I pictured the heating as a bell curve, with a sweet spot which is determined by the amps. It is the distance between the actual resistance and the sweet spot which determines heat and you were closer with only one element. Doubling this increased the distance and caused for less energy density. I have held this in my mind for years and used it to logically predict how efficient heating elements would be with great success. The conclusions I made regarding the experiment were predictions based on assumptions. Hearing it explained this way confuses me and without mathematics to analyze the results, I may be completely wrong. I would like a deeper explanation over this if you find time. Thank you and keep up the good work
If you want twice the heat, then you will have to use twice the power
You got it.
GFM
I don't believe you are actually adding more resistant I believe after you put those in series and take an ohms reading you will have less resistance
You would be wrong. Ohms law.
GFM
If you connect loads in series, you INCREASE the resistance. You're probably getting confused with parallel connections.
Review physics concept my dear
You must be more specific. Where did I go wrong.
GFM
ehm you double the resistance and call it lower?
Yes. If you double the resistance, you will halve the amperage draw.
GFM
@@grayfurnaceman but you have to consider the material being used too. You've gone past the optimal resistance for this material, resulting in the drop in amps
@@rocki_bb I fail to understand what "optimal resistance" is. This is a simple example of ohms law.
GFM
You have shown that relationship between current and resistance, but it somewhat twists the relationship to heat/power you're trying to imply.
A better experiment/presentation would be running the same amount of voltage through pieces of copper wire and nichrome wire, both with the same diameter, length, and turns. It will clearly demonstrate that increased resistance = increased heat.
This also shows why in various situations heating elements are combined with things like ceramic and quarts
@@rocki_bb Your basic understanding of resistance, amperage flow and power used is flawed.
I effectively did your experiment. Its the point of this video. the higher resistance wire consumed less amperage (energy) than the lower one.
Ceramic is used in electric heaters, not as a conductor but as a heat radiant.
GFM
you don`t need too much amp,try with more voltage and ypu gonna get good results.
Myth? you just added more surface area for the energy and reduced the resistance by allowing the current more time to flow. It is the backup of to much current that generates the heat. If you restrict the current input on your first example you would have gotten the same result as your second example. A rheostat is a variable resistor which is used to control current flow into the elements either tungsten or nichrome wire because of their high resistance to temperature and current flow. SO simply put the more current you try to cram down the wire the hotter it will get. Volume and pressure. "SLAPS FOREHEAD AND WALKS AWAY in dis belief!" :)
Unfortunately, you are completely wrong here. Electricity does not work that way. This is exactly the reason for this video. I know it seems that if I increase resistance, the energy to overcome the resistance will increase. Such as if I travel up hill in a vehicle, the resistance to my moving up increases and more energy is used. In electricity that does not happen. If I increase the resistance to flow, as I did when I added the 2d element I doubled the resistance to flow. That halves the current. If you rewatch the video it is obvious. Consider if I placed a short copper wire in an outlet. One end of the wire in one side of the plug, one end in the other. Very low resistance. That would, using your thinking, mean very little current would flow. The actual result is a "short", aptly named. The circuit protection would immediately open. That is because the current flow was very high. In the thousands of amps. Think about it.
GFM
@@grayfurnaceman this is properly a stupid question... but i just have to ask... if the circuit in series draw less amps... where does that force go? if force is a constant... shouldnt that mean that if the circuit is applyed the same amount of force, the path whith most resistans, has a bigger change from moving energy (electrons moving) to heat energy (electrons stopping and turning in to heat)?
im just curious...Loved the video btw... keep opp the good work!
The understanding of electrical energy is quite easily misunderstood.
Resistance is like a valve on a water line. the water passing thru is the energy expended. High resistance is like the valve being opened just a small amount. If I increase the pressure (voltage), more will pass thru if the valve opening has not changed.
Also, electrons do not change speed. Just the number of them passing is decreased when the valve is restricted. When the electron passes thru it effects the material it is passing thru. Something like a vehicle driving at a fixed speed thru air. The air is displaced by the vehicle and the air is heated as the vehicle passes. Not a perfect analogy, but pretty close.Hope this helps.
GFM
bruh headphone users rn 💀💀
So basically it seems 4 years ago everyone was dumb. Who told you power increase with resistance, it will increase or decrease depending on whether voltage source is independent or current source is! that is P(heat) = V²/R or P(heat) = I²R.
And btw, it is called resistance heater because it's inductance is negligible and is kind of purely resistive load, otherwise manufacturer would have named it induction heater. Also ideally induction heater shouldn't feel warm to touch but it does, because it still has ESR to some extent.
I wouldn't have commented on such a old video but the level of stupidity in comments section forces me to do so
More resistance in series less heat more resistance in parallel more heat
First half ok.
In parallel circuits, reduced resistance also increases heat.
GFM
@@grayfurnaceman I though so I just said things backwards
It resists the flow of current
If this is correct, then higher resistance would increase heat output and larger amperage draw. This is not the case.
GFM
Dude, you never increased the power when connecting the elements in series. You can't display a proper comparison unless you bring both circuits to the same temperature.
You need to learn how thing operate before you make a claim because all your doing is confusing people.
@@NoName-ly9xl The point of the demonstration is to show that increased resistance will reduce, rather than increase current flow in a circuit. It is a common myth that increased resistance will increase current flow. temperature is not part of the equation.
GFM
u mesed up... "if i lower resistance ill get half the heat" oposite way
You are correct at around min 2:45. Other locations in the video it is correct.
GFM
P=I(IR)=I^2R=Joule Heating, it's not a myth it's science.
power or energy
?
That’s unnecessary. I just went with ohms law and was convinced enough.
Yeah, it is proportional to the resistance, so the power of heating goes up linearly as the resistance goes up. On the other hand, the power of heating increases exponentially as the current increases.
So, when the heating elements are put in series, the resistance is doubled, but the current is cut in half. The net effect on the power of heating is that it's cut in half (0,5^2 * 2 = 0,5).
Ai două termorezistente
I don't think this guy has the slightest understanding of at least the 2 basic ohm's law formulas: V/R=A and VA=W and no understanding of series vs parallel circuits and formulas either.
increase resistance decrease the current so decrease heat . heat couse by resistance of material.
The first part of your statement does no fit with the last part. How can resistance cause more heat if the resistance is increased you get less heat.
GFM
@@grayfurnaceman Power=I2R (joule Heating)
The formula notwithstanding, you still move less current if you increase resistance. Perhaps instead of calling it resistance heat, maybe we should call it lack of resistance heat.
GFM
Well, because the heat generated is caused by the resistance of the material I guess😅
The heat generated is not from resistance. That is proved by ohm's law. Lower resistance equals more heat.
GFM
No, well resistivity is inverse of conductivity. And reflects as a concept the inperfection of materials ability to ‘move’ electrons through it. It’s a bit like friction. Imagine a stream of electrons rushing through with some speed a bumping into uneaven surface, potholes and such. Each time they dissipate a little bit of heat. Ohms law illustrates this where the current is equal to potential divided by resistance. So in our analogy you would have charged potential e.g. kinetic energy and the flow through this pipe or surface would be dictated by how condusive is this surface or pipe to the flow of electrons. So the lost energy would change into heat. (ref. thermodynamics) Say wood would be so highly resistive that the electrons would not even flow ... but in these instances the circuit is not even closed for practical purposes and hence nothing happens...
@@stevenrachko8696 Do the numbers. Reduce the resistance and the amperage goes up.
Your analogy of kinetic energy does not apply to electricity. It is not friction, thermodynamics does not apply here.
Your wood analogy would mean extreme resistance would increase heat. It does not.
GFM
well just double the voltage and you’ll get twice the heat... that is all there is to it. Alternatively you can just use a more resistive wire with same voltage (make it thinner or longer or use a different material). It is that simple and that analogy is used to illustrate the fundamental processes that cause this...
en.m.wikipedia.org/wiki/Joule_heating
If a furnace repairman came to my house with this half true logic, I would not let him touch my furnace. He might be a good furnace tech, but his point is lost to those educated in ohms law.
No, you seem to be the one who is confused. Ohm's Law states that Voltage/Resistance=Current. So if you either lower the voltage or increase the resistance, there will be LESS current flow. In the video, he connected 2 heater elements in series, which doubled the resistance and therefore there was less current. So the heater elements didn't get as hot. His point was to show that a lot of people have a total misunderstanding about how electricity works and mistakenly think that "resistance means more heat" which is actually the exact opposite of reality.
you need to learn some physics first before starting playing with electricity to increase the heat need to lower the resistance of the element
Perhaps you should rewatch the video.
GFM
Don't make comments before you watch the video over and over. He knows his stuff. You are the confused one