Sir, you are one of the best HVAC teachers on the Internet. I tip my hat to you. God has truly blessed you with the ability to communicate complex ideas in a simple way. We cannot thank you enough for all you have done for us.
1,2,5 relays are one of the most overlooked parts in diagnosing a so called bad compressor. Many unseasoned Techs don’t understand them, they are very simple but extremely critical. You explained them perfectly, I hope less experienced techs will take a little time to watch this video.
Great video, thanks for putting this together. I'm familiar with these in well pump controllers, where they serve the exact same purpose -- put the start cap in the circuit to get the pump motor running, and then remove the start cap from the circuit. Although, I never knew exactly how they worked -- and now I do!. You have to love the simplicity! Thanks again.
Great explanation as always! Could you possibly make a video of wiring a potential relay, start cap, run cap and the compressor coming from the contactor? Thanks and great job as always JMT!
Thank you once again for the easy to follow explanation on a rather confusing piece of item the potential relay. I know understand it better. Thanks to you and your depth knowledge of this field. I wonder if you can help me and others like me with the pictorial sketch and explanation of the wiring on freezer box with the power connection, dual pressure switch, thermostat, solenoid valve, defrost timer and heater connection starting from the very same box with normally house the potential relay, start and run capacitor.
Back EMF is generated in the motor itself. Pick-up voltage, generally speaking, 0.75 percent of total back emf of motor start winding at operational speed. Relay only sensing back emf of start winding.
As a 5 yr old.... I now understand this perfectly. Our brains are configured to think coil voltage will close/make the circuit (N.O.).... this concept (N.C.) is opposite and I believe the reason for difficulty understanding. Thanks and following.
Never understood nor took the time to see how those worked. Thanks for the excellent explanation and keep these types of videos coming. BTW… You sound a lot like my cousins from Long Island, lol.
How would you test this component on a system? What symptoms would indicate a bad relay? I ask because I found one of these with the points welded closed and wouldn’t open. The compressor started for a second and then would shut off so I guessed this was the faulty component and it worked for me, but I’d like to test it next time
Could you do a similar video as this one but show with arrows the flow of electricity through the system? How the compressor and fan start and how the electricity flows through the capacitor and through the 521 relay. Thanks
I've always shrugged when thinking about how back EMF can increase voltage across a motor to well above the incoming voltage from the source. After all, if voltage across the windings is 470V, and if incoming voltage is 240V, why doesn't current go backwards up the line? What drives current to continue flowing antegrade to a higher potential leading into the motor? The only thing that comes to mind is the phase shift that you see in a normal RLC circuit, which happens even in a simple inductor without back EMF.
In our Class the Run Capacitor is tied in to one of the terminals from the start Capacitor and then ties in to L2 but here it's different. Can someone plz explain? Would very much appreciate it.
Bonjour, la valeur du condensateur est de 88 microfarad 250v. Peut-on remplacer un condensateur de même valeur 330v? Sans le compresseur danfost ne subisse aucun dommage ? Aidez-moi svp
Trying to understand how the system works with a contractor and no potential relay. The unit I'm looking at has a contactor and no potential relay. The start capacitor was replaced and blew up in 30 seconds so I thought stuck potential relay but all I see is a contactor.
Because the coil has to pull the pole up which opens the contacts and taking the start winding out of the circuit. If you mount the relay upside down the Normally closed contacts will be open thus not putting the capacitor in the circuit and the pole couldn't pull up because it would already be up. The pole moves freely in your hand when you flip it over. If you put a ohmeter on contacts 1 and 2 it will show continuity and when you turn it over the contacts will OPEN. Test one and you will see!!
Hello, I have one of these 521 in a 240v 3 phase converter (Cedarberg 75A), i have doubt if it is good or not, as this converter does not have/use run capacitor. Can this be possible in you experience ? Actually is a 240v motor converter, but the capacitor says 120V
Very informative video. I do have one question though. On the side of the potential relay there are numbers and letters. Do they mean anything and if so how do we read them? For example on the relay you demonstrated RVA3AG6D 917 U433 the three sequences of numbers and letters do they represent the specs and model number if not what do they mean? Thanks in advance.
The it was explained to me was that the compressor when running creates its own voltage like how electricity is created at a hydro electric plant. After all it is just a rotor and stator.
Otashionly realy enszing ac refrgatshion systom coil enszing coil rmf enger portshion coil power comp high portshion systom flowing coil using ruing point starting poin coil cap and cntacting coil engzing emf and coil poteshson rrly uding l1 l2 numbe usinv
in uk we dont use the line 2 that is very confusing, we say neutral or N, line 2 is associated with 3 phase poer supply only. please use the neutral word instead if demonstrated your idea, dangerous
Pretty cool my guy, you have a gift on how to teach anything. May God bless you
Best explanation of what that device does. I couldn’t figure out why it can only be oriented one way. Now I know! Keep up the great videos!
Sir, you are one of the best HVAC teachers on the Internet. I tip my hat to you. God has truly blessed you with the ability to communicate complex ideas in a simple way. We cannot thank you enough for all you have done for us.
Vrey very good potshionall rel emf sfety ac. Systomm no .521 power give l1 l1 enrzing coil
1,2,5 relays are one of the most overlooked parts in diagnosing a so called bad compressor. Many unseasoned Techs don’t understand them, they are very simple but extremely critical. You explained them perfectly, I hope less experienced techs will take a little time to watch this video.
In what circumstances can a potential relay go bad?
Thank you from a pipe fitter apprentice. Making it seem easy!
Interesting and helpful video. Great job JMT as always.
Great video, thanks for putting this together. I'm familiar with these in well pump controllers, where they serve the exact same purpose -- put the start cap in the circuit to get the pump motor running, and then remove the start cap from the circuit. Although, I never knew exactly how they worked -- and now I do!. You have to love the simplicity! Thanks again.
Great video once again. Excellent explanation as well keep up the great work
Tyvm! Very succinct. I will forward this to our Service Department Technicians.
This is a phenomenal explanation.
Very good from UK England
great video JMT. very helpful info!!
Great explanation as always! Could you possibly make a video of wiring a potential relay, start cap, run cap and the compressor coming from the contactor? Thanks and great job as always JMT!
Great video
Thank you once again for the easy to follow explanation on a rather confusing piece of item the potential relay. I know understand it better. Thanks to you and your depth knowledge of this field.
I wonder if you can help me and others like me with the pictorial sketch and explanation of the wiring on freezer box with the power connection, dual pressure switch, thermostat, solenoid valve, defrost timer and heater connection starting from the very same box with normally house the potential relay, start and run capacitor.
Back EMF is generated in the motor itself. Pick-up voltage, generally speaking, 0.75 percent of total back emf of motor start winding at operational speed. Relay only sensing back emf of start winding.
Glad someone pointed this out. Its the back-EMF from the start winding that causes the relay to open !
Nice work here. I followed the explanation and it work for me. I have release the report of this video on my profile
As a 5 yr old.... I now understand this perfectly. Our brains are configured to think coil voltage will close/make the circuit (N.O.).... this concept (N.C.) is opposite and I believe the reason for difficulty understanding. Thanks and following.
thanks...iam from Indonesia
Helpful video, thank you Sir for sharing this video
Thank you for sharing this valuable information
Another banging vid. Troubleshooting tips and tricks?
Yes sir thanks for your knowledge
👍💪❄🙏🇺🇸 another great presentation. There's always voltage at 5 n 2 n then when call for cooling it goes up n opens contacts.
Never understood nor took the time to see how those worked. Thanks for the excellent explanation and keep these types of videos coming. BTW… You sound a lot like my cousins from Long Island, lol.
Thanks mate for heads up, this video actually help wired one myself. Jumper man tech still the best.
Good video
Just subscribed. Thanks for the information. Great video.
Great vid….. question, will a bad potential relay cause my compressor to cut on and off 10 seconds?
Wonderful....... Very helpful video for me🙏 🇮🇳🙏💐☺🕉🙏
How would you test this component on a system? What symptoms would indicate a bad relay?
I ask because I found one of these with the points welded closed and wouldn’t open. The compressor started for a second and then would shut off so I guessed this was the faulty component and it worked for me, but I’d like to test it next time
Great video as usual 👌
Thank for your videos a lot important information
Your follow 🇮🇶iraq
Great explanation, how can I know if this relay is not working properly or damaged
Thanks!
Thank you so much! Really appreciate that 🙏 Totally made my night. Thanks for watching & stay tuned for new videos every week 🔧⚡️🤙
Could you do a similar video as this one but show with arrows the flow of electricity through the system? How the compressor and fan start and how the electricity flows through the capacitor and through the 521 relay. Thanks
What about if don’t have a potential relay, or start cap. Are there any alternatives in a pinch
Great explanation thanks
I've always shrugged when thinking about how back EMF can increase voltage across a motor to well above the incoming voltage from the source. After all, if voltage across the windings is 470V, and if incoming voltage is 240V, why doesn't current go backwards up the line? What drives current to continue flowing antegrade to a higher potential leading into the motor? The only thing that comes to mind is the phase shift that you see in a normal RLC circuit, which happens even in a simple inductor without back EMF.
In our Class the Run Capacitor is tied in to one of the terminals from the start Capacitor and then ties in to L2 but here it's different. Can someone plz explain? Would very much appreciate it.
Nice video! Thank You.
Thanks for the precise explanation. I will like to know if both potential relay and the current relay can be used together on a compressor.
Bonjour, la valeur du condensateur est de 88 microfarad 250v. Peut-on remplacer un condensateur de même valeur 330v? Sans le compresseur danfost ne subisse aucun dommage ? Aidez-moi svp
thanks
Trying to understand how the system works with a contractor and no potential relay. The unit I'm looking at has a contactor and no potential relay. The start capacitor was replaced and blew up in 30 seconds so I thought stuck potential relay but all I see is a contactor.
Can u ues this realy just for start capacitor?
Why is it important to orient the relay vertically? Thankyou
Gravity...
Because the coil has to pull the pole up which opens the contacts and taking the start winding out of the circuit. If you mount the relay upside down the Normally closed contacts will be open thus not putting the capacitor in the circuit and the pole couldn't pull up because it would already be up. The pole moves freely in your hand when you flip it over. If you put a ohmeter on contacts 1 and 2 it will show continuity and when you turn it over the contacts will OPEN. Test one and you will see!!
Pretty cool, thank you
Great video.....I guess here in the UK your L2 is our Neutral....right? 🙂
Hello, I have one of these 521 in a 240v 3 phase converter (Cedarberg 75A), i have doubt if it is good or not, as this converter does not have/use run capacitor. Can this be possible in you experience ? Actually is a 240v motor converter, but the capacitor says 120V
Very informative video. I do have one question though. On the side of the potential relay there are numbers and letters. Do they mean anything and if so how do we read them? For example on the relay you demonstrated RVA3AG6D 917 U433 the three sequences of numbers and letters do they represent the specs and model number if not what do they mean? Thanks in advance.
interesting, but I miss one thing : what happens to 2 after starting up? what's the electric potential at 2?
Top Draw 💯💯💯👍👍👍
The it was explained to me was that the compressor when running creates its own voltage like how electricity is created at a hydro electric plant. After all it is just a rotor and stator.
I think the terminal of relay 1&2 had interchange please check
The 4 or 6 termanal Could be used as a neutral right?
,hello sir,, very nice explanation..may i ask a question what f the close contact of potential relay will not open?
What's that music at the end?
Do Universal Pontential Relays work good? Even If all their specs match?
I need to record this diagram in my brain
5 -2-1 Common - Start - Run 👍
very nice I'm a plumber. do they go bad offen I like knowledge
Probably should explain that the coils becomes an electromagnet and that is what caused the contacts apart and opens the circuit
Agree, it would add a bit more clarity.
👍👍👍
👍👍👍🙏🔧⚡️🤙
5 21 reay potacte realy enizing hot potact capcater us img ac systom ..
👍
Otashionly realy enszing ac refrgatshion systom coil enszing coil rmf enger portshion coil power comp high portshion systom flowing coil using ruing point starting poin coil cap and cntacting coil engzing emf and coil poteshson rrly uding l1 l2 numbe usinv
in uk we dont use the line 2 that is very confusing, we say neutral or N, line 2 is associated with 3 phase poer supply only. please use the neutral word instead if demonstrated your idea, dangerous
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