Glad to see you gave it a shot - and you can do this with basically any standard transformer. I once used a universal input voltage type 24v control transformer as an autotransformer to boost 120v to 240v (it had primary windings for 120/208/240/480) to power a device that a customer accidentally ordered in the wrong input voltage for a panel that only had a 120v feed.
Haha, love this video, couldn't hardly you hear you anymore after the Goodman fired up, lol. I used a transformer like that one a long time ago, back in the 1990's, but in a boost setup instead of buck. Had a Hoshizaki ice flaker machine (2000 pound per day) that was setup for 230volts single phase, and it did not like the 208 volts at that building at all. It was more like 204-206 at the equipment room way up on the roof. So I got a 1kva 208-230 boost transformer, which ended up at like 228-232 at the ice machine. What you do to calculate how big of a transformer you need for either buck/boost is really simple. Just multiply the voltage DIFFERENCE by full load amps, not the full 208 or 240. So that's why the 0.500 kva transformer you have is plenty big enough for that AC unit, because you're only pulling 11 amps times (240-225) = 165 VA. Or in your real world measurements 249-230=19 volts times even 20 amps you'd still be at only 380 voltamps. Which is probably close to the max since the ambient temp is so hot there and that transformer doesn't have much of a heat sink.
Me thinks the slightly increased voltage could be from solar being fed back to the utility. The frequency is locked in but the voltage has to increase to feed unused energy back to the grid resulting in the higher voltage where your measuring it. It could be yours or a nearby neighbor that's contributing back to the grid. All the rotors in all the generators on your grid are magnetically coupled together so the frequency will not change but the voltage is variable depending on length to your pole transformer and load. For someone to feed power back to the grid the voltage must increase to reverse the flow of current back to the grid so your neighbors can use some of your extra current. Could be way off but that's my opinion. Awsome work. Very inspiring thank you.
He’s mentioned for months that his utility voltage runs hot. not that uncommon, and reduces grid losses / increases grid capacity slightly. Backfeeding is not possible in this set up because all the DC is blocked by a full wave diode bridge rectifier. Same circuit that stops a fully charged Tesla plugged into your garage from back feeding ..
I meant backfeeding as in when his large inverter puts the extra watts back to the grid, not dc backfeeding. For him or any of his neighbors to be able to contribute their unused extra power back to the utility grid the voltage must be slightly higher thereby increasing the measured voltage a volt or two. It would be interesting to see if the voltage changes at dawn and dusk, if there is a measurable difference when those around that area with large solar are actually increasing it or if its just typical changes in demand causing his feed to run hot. I heard teslas are capable of helping the grid but it is not currently enabled via software. I don't know much about teslas other than hearsay.
@@jamminwrenches860 does he have a grid tie inverter? i think his 11 panels in series just feeds straight into the VFD DC bus. solar sans inverter. regardless of his setup, you make a good point in that neighbors with grid tied solar installations could have that effect. the utility might pump out 250 w the assumption that transmission voltage drop will be ~10 volts but then this doesnt come true with micro-local generation. interesting topic to see how utilities handle this. re teslas to grid, probably would need to tap the DC charging line and use an outboard inverter. i don’t think the AC charging line can work bi-directionally (tesla’s own statement, citing bridge rectifier ..)
What you speak of is impossible. The solar feeds DC POWER to the VFD which is after the diodes (rectifiers). No voltage can flow from the DC power supply to the AC utility. I think you are thinking of the *TYPICAL* installation which is a solar array using a "grid tie" inverter that supplies power into the AC power grid. I am not doing that. (My rooftop Tesla panels do that, but not my DIY system). The utility voltage is just a tad high here. If you watch some of my recent videos since I added that voltage/amp panel meter into my utility power service disconnect you will see that the AC voltage does not change when I put the disconnect. The reason I lower my utility voltage is to keep the rectified DC (from the utility voltage) down below what my solar can supply during the day that way no current draws from the utility power until the solar voltage sags enough. These systems are interconnected at the Heat Pump *variable speed drive.* Only diodes separate them.
There are a lot of grid tie solar in my hood. And yeah, @yeliab814 I have 11 panels in series (twice) that are parallel together. Making it a *11S 2P* array. 22 30VDC panels = 330VDC Plugged directly into the DC bus of the variable speed drive. There is no inverter on my DIY solar system. The inverters seen on the side of the wall there are the Tesla/Solar City. Totally separate grid tie system that I've had for several years now.
Maybe. I may need more panels. Low speed fan probably is no big deal but full speed might actually pull some power. I think it was around 2 amps at 230VAC. But way less on lower speed when it runs on 1st stage. I would need something to provide the 24VAC controls for the stat and whatnot.
@@jakeandrules7724 No. This is a totally separate off grid array of panels I set up in my back yard. I do also have rooftop grid tie which is why you may see the inverters for that on my wall in the background of my video clips. My DIY system is separate and it's wired and connected as high voltage DC. No inverters are involved at all. The reason I do that is because some variable speed HVAC actually operates off of high voltage DC internally (VFD for compressor, ECM for outdoor and indoor fans) and there's no need to add an inverter to make AC power that's only going to get rectified back to DC power in the above mentioned hardware.
Oh, you mean my Tesla panels and the neighbors? Yeah that could be. As it would be how they supply the power. There are grid tie panels on my home and all around me.
Yes, basic grid tie inverters are current sources, not voltage sources. The inverter raises the AC line voltage to where current will flow in reverse. This is also why you can't use basic solar inverters stand alone unconnected to the grid. They must have a low impedance load to push against.
finally....well done. 24v would have been the sweet spot not 16, but this is close enough. prob still worth testing 32v. that reactor looks good, if anything it may be too big. although the more i think about it, it’s probably not be worth the time installing it. the reason is that it won’t have much reactance at lower current , such as when you’re running principally on solar and sipping off the mains. it won’t do anything. you would need a much lower current rated reactor which has much higher induction, but you don’t have that option because you need to be able to handle the higher current. so that huge reactor will do its job at night when the solar is off, but since you aren’t paying for apparent power, do you really care.. I put those questions together in a comment on the other video - would appreciate if you can take a look.
Cool.. By the way, I’m the guy who has been helping you and writing all the stuff and persistently pushing you to discover autotransformers. I’ve sent you some questions and I cant understand why you don’t respond at all? I’ve put a lot of thought into helping you solve your problem with your system, but If you don’t want to help me at all , that’s cool, just please say so. Here were my questions again: Basically I am doing a fairly similar project in that I’m converting my 5ton ac to all variable speed. I have installed motors/VFD’s for evap&cond fans; next is install 3ph scroll and VFD. So I was curious: -do you have recip or scroll, and how low Hz do you go? -what VFD power/current rating do you have, for the 3ton(correct?) compressor? Any issues starting it? -any oil return/sump issues, and any opinion on how low Hz I can run my zr61kce/tf5 ? Do you think it makes sense to run a periodic run up to say 50Hz-60Hz when running at low speeds (30-40Hz)? -Are you just running 2 stage 40 / 60? I was thinking about controlling comp speed on PID using perhaps suction pressure transducer, but cant think of a good control strategy. Maybe simpler would be to vary evap fan and comp speed in unison based on a PID linked to temp setpoint. -any other helpful thoughts in making such a conversion? There seem to be very few people who have done this .. many thanks
Nice. Glad you’ve got that part dialed in. What’s next? More panels will sun tracking capability so you can do the air handler and prepare for the demise of your prized Goodman.
I am in a HOA so I made the array on the stealth. LOL I may add some more panels later to try a mini split for the garage next. Thos may go on my back patio and likely angled a little for that Afternoon sun.
@@hackfreehvac I used to live out there. The HOA can be brutal . I now live in a hole in the woods with no neighbors. Love it! Please keep us updated on the project and results on the electric bill.
@@hackfreehvac once you do that you you’ll wonder why you didn’t do it to begin with. I live in eastern NC 20miles out of town on acreage with no neighbors. Quiet. All the work I want and peace when I want it, except for my wife of course 😂. Wish I’d been in Hvac when I lived in Phoenix. Hindsight I probably would’ve stayed. The
Variable Frequency Drives have the rectifier inside. You connect AC voltage right to them (ordered for 230V or 460V 3 phase motors typically). And some have DC Bus connections on them so you can supply DC right to the capacitors. Working on VFD's on commercial HVAC is what gave me the idea to just skip the typical solar panels + charge controller + inverter (single phase) that is typically purchased. 😆 With the VFD in just feeding the utility power into the AC input (how they are typically used) but then connect my solar DC to the Bus after the rectifier. When then solar voltage is higher the AC input simply shuts off because the diodes don't switch on when the input is less. The transformer knocked my utility power voltage down a few volts to keep it under where the solar is during sun exposure. It worked so I just kept refining it. Much of the parts were parts I acquired. So I don't have much in it.
@@hackfreehvac thanks for the info! very cool. i figured it may have been that simple, but devils in the details! i’ve played with some of the ABB VFD’s in my building at work but didn’t realize there was a way to do both AC & DC inputs on some of them. taught myself how to control the ABB’s recently; wound up installing a Click PLC and using the PID loop to drive the blower motor to keep static pressure more constant throughout the day. then added a pneumatic transducer to drive the chilled water valve. I’m controlling my roof AHU’s fan wall / valve via bacNet with some python scripts i wrote. fun stuff, but not as fun as high voltage DC experiments! lol. it’s all temporary as we’re installing all new ddc controls throughout the building (Delta), getting a new air handler and a new air cooled chiller (the permit was finally approved on Friday!!). Fun HVAC times ahead! thanks for your vids! keep up the good work.
Can I ask total newbie looking to buy an install the growatt 3000, mmpt, solar linked to breaker box etc. Wat does this transformer do and why is it so important? Any links be great
I was wiring high voltage direct to the heat pump 3 phase VFD in this case. No solar charger/ inverter. Just two sets of 11 panels in series for 330VDC I used that transformer to slightly lower my utility voltage from almost 250vac (over 330VDC rectified)down to something like 220 so that when the solar voltage was higher it would draw from the solar Higher solar DC voltage meant that the diodes from the lower AC supply didn't turn on as a way to automatically switch over from utility to solar. It was an out of the box experiment. I am more using a solar charger inverter and connected to the water heater and batteries instead
You mean that slight fan speed oscillation we heard? That is the electronic fan motor for the condenser. Runs separate form the VFD. IT only did it a few times and usually when I abruptly pull the disconnect etc. I haven't noticed it before that or any other time it is running so I am not worried about it.
@@CraigDohner Oh. The panels just can't power it at 60Hz except at high sun. Like noon until maybe 2 it might. Then it can't. It's been handling 40Hz (1st stage) until at least 4:30 though.
Wouldn’t it be Better to Have the Solar Panels hooked to a Battery 🔋 Bank and Pull Off to Several inverters. That Way You can Keep adding Solar Panels till the Cows come home !
VFD. They were new but never used from a change out a few years ago that had the wrong voltage VFD's installed. They sat in a warehouse for a year or so. Someone there knew I'd take them. :-D
Glad to see you gave it a shot - and you can do this with basically any standard transformer. I once used a universal input voltage type 24v control transformer as an autotransformer to boost 120v to 240v (it had primary windings for 120/208/240/480) to power a device that a customer accidentally ordered in the wrong input voltage for a panel that only had a 120v feed.
That's awesome.
Haha, love this video, couldn't hardly you hear you anymore after the Goodman fired up, lol. I used a transformer like that one a long time ago, back in the 1990's, but in a boost setup instead of buck. Had a Hoshizaki ice flaker machine (2000 pound per day) that was setup for 230volts single phase, and it did not like the 208 volts at that building at all. It was more like 204-206 at the equipment room way up on the roof. So I got a 1kva 208-230 boost transformer, which ended up at like 228-232 at the ice machine. What you do to calculate how big of a transformer you need for either buck/boost is really simple. Just multiply the voltage DIFFERENCE by full load amps, not the full 208 or 240. So that's why the 0.500 kva transformer you have is plenty big enough for that AC unit, because you're only pulling 11 amps times (240-225) = 165 VA. Or in your real world measurements 249-230=19 volts times even 20 amps you'd still be at only 380 voltamps. Which is probably close to the max since the ambient temp is so hot there and that transformer doesn't have much of a heat sink.
Nice.
Me thinks the slightly increased voltage could be from solar being fed back to the utility. The frequency is locked in but the voltage has to increase to feed unused energy back to the grid resulting in the higher voltage where your measuring it. It could be yours or a nearby neighbor that's contributing back to the grid. All the rotors in all the generators on your grid are magnetically coupled together so the frequency will not change but the voltage is variable depending on length to your pole transformer and load. For someone to feed power back to the grid the voltage must increase to reverse the flow of current back to the grid so your neighbors can use some of your extra current. Could be way off but that's my opinion. Awsome work. Very inspiring thank you.
He’s mentioned for months that his utility voltage runs hot. not that uncommon, and reduces grid losses / increases grid capacity slightly.
Backfeeding is not possible in this set up because all the DC is blocked by a full wave diode bridge rectifier. Same circuit that stops a fully charged Tesla plugged into your garage from back feeding ..
I meant backfeeding as in when his large inverter puts the extra watts back to the grid, not dc backfeeding. For him or any of his neighbors to be able to contribute their unused extra power back to the utility grid the voltage must be slightly higher thereby increasing the measured voltage a volt or two. It would be interesting to see if the voltage changes at dawn and dusk, if there is a measurable difference when those around that area with large solar are actually increasing it or if its just typical changes in demand causing his feed to run hot. I heard teslas are capable of helping the grid but it is not currently enabled via software. I don't know much about teslas other than hearsay.
@@jamminwrenches860 does he have a grid tie inverter? i think his 11 panels in series just feeds straight into the VFD DC bus. solar sans inverter.
regardless of his setup, you make a good point in that neighbors with grid tied solar installations could have that effect. the utility might pump out 250 w the assumption that transmission voltage drop will be ~10 volts but then this doesnt come true with micro-local generation. interesting topic to see how utilities handle this.
re teslas to grid, probably would need to tap the DC charging line and use an outboard inverter. i don’t think the AC charging line can work bi-directionally (tesla’s own statement, citing bridge rectifier ..)
What you speak of is impossible.
The solar feeds DC POWER to the VFD which is after the diodes (rectifiers).
No voltage can flow from the DC power supply to the AC utility.
I think you are thinking of the *TYPICAL* installation which is a solar array using a "grid tie" inverter that supplies power into the AC power grid. I am not doing that.
(My rooftop Tesla panels do that, but not my DIY system).
The utility voltage is just a tad high here.
If you watch some of my recent videos since I added that voltage/amp panel meter into my utility power service disconnect you will see that the AC voltage does not change when I put the disconnect.
The reason I lower my utility voltage is to keep the rectified DC (from the utility voltage) down below what my solar can supply during the day that way no current draws from the utility power until the solar voltage sags enough.
These systems are interconnected at the Heat Pump *variable speed drive.* Only diodes separate them.
There are a lot of grid tie solar in my hood.
And yeah, @yeliab814
I have 11 panels in series (twice) that are parallel together. Making it a *11S 2P* array.
22 30VDC panels = 330VDC
Plugged directly into the DC bus of the variable speed drive.
There is no inverter on my DIY solar system.
The inverters seen on the side of the wall there are the Tesla/Solar City. Totally separate grid tie system that I've had for several years now.
Now hide all your tools and and set up some hidden cameras and audio then call some companies for no cool call
Lmao I had the same thought. Call a Goodman tech.
That’s so mean! You have to do it! Hysterical to observe 🤣
Could you imagine? HA HA
Made me lol
Ya but then they'd start hacking, and make a mess of things. This house has to remain 'hack free'...
Now to do air handler so you can run air conditioner when power is out
Maybe. I may need more panels. Low speed fan probably is no big deal but full speed might actually pull some power. I think it was around 2 amps at 230VAC. But way less on lower speed when it runs on 1st stage.
I would need something to provide the 24VAC controls for the stat and whatnot.
@@hackfreehvac you can handle it. Maybe you could have it lock it in low for power goes off
Thats a grid tied system correct? If so, you lose all power so it wont backfeed if there is an outage. Again, not sure on your total system.
Does your indoor unit utilize a dc buss like your outdoor unit?
@@jakeandrules7724
No. This is a totally separate off grid array of panels I set up in my back yard.
I do also have rooftop grid tie which is why you may see the inverters for that on my wall in the background of my video clips.
My DIY system is separate and it's wired and connected as high voltage DC.
No inverters are involved at all.
The reason I do that is because some variable speed HVAC actually operates off of high voltage DC internally (VFD for compressor, ECM for outdoor and indoor fans) and there's no need to add an inverter to make AC power that's only going to get rectified back to DC power in the above mentioned hardware.
The high voltgae on your grid has to do with the solar power connected to the grid.
Oh, you mean my Tesla panels and the neighbors?
Yeah that could be. As it would be how they supply the power.
There are grid tie panels on my home and all around me.
@@hackfreehvac exactly, we had some troubles where the over/under voltage safety kept tripping on condensing units.
Yes, basic grid tie inverters are current sources, not voltage sources. The inverter raises the AC line voltage to where current will flow in reverse. This is also why you can't use basic solar inverters stand alone unconnected to the grid. They must have a low impedance load to push against.
finally....well done. 24v would have been the sweet spot not 16, but this is close enough. prob still worth testing 32v.
that reactor looks good, if anything it may be too big. although the more i think about it, it’s probably not be worth the time installing it. the reason is that it won’t have much reactance at lower current , such as when you’re running principally on solar and sipping off the mains. it won’t do anything. you would need a much lower current rated reactor which has much higher induction, but you don’t have that option because you need to be able to handle the higher current. so that huge reactor will do its job at night when the solar is off, but since you aren’t paying for apparent power, do you really care..
I put those questions together in a comment on the other video - would appreciate if you can take a look.
As I am around more VRF stuff I may get my hands on a smaller reactor eventually.
Cool.. By the way, I’m the guy who has been helping you and writing all the stuff and persistently pushing you to discover autotransformers. I’ve sent you some questions and I cant understand why you don’t respond at all? I’ve put a lot of thought into helping you solve your problem with your system, but If you don’t want to help me at all , that’s cool, just please say so. Here were my questions again:
Basically I am doing a fairly similar project in that I’m converting my 5ton ac to all variable speed. I have installed motors/VFD’s for evap&cond fans; next is install 3ph scroll and VFD. So I was curious:
-do you have recip or scroll, and how low Hz do you go?
-what VFD power/current rating do you have, for the 3ton(correct?) compressor? Any issues starting it?
-any oil return/sump issues, and any opinion on how low Hz I can run my zr61kce/tf5 ? Do you think it makes sense to run a periodic run up to say 50Hz-60Hz when running at low speeds (30-40Hz)?
-Are you just running 2 stage 40 / 60? I was thinking about controlling comp speed on PID using perhaps suction pressure transducer, but cant think of a good control strategy. Maybe simpler would be to vary evap fan and comp speed in unison based on a PID linked to temp setpoint.
-any other helpful thoughts in making such a conversion? There seem to be very few people who have done this .. many thanks
Nice. Glad you’ve got that part dialed in. What’s next? More panels will sun tracking capability so you can do the air handler and prepare for the demise of your prized Goodman.
I am in a HOA so I made the array on the stealth. LOL
I may add some more panels later to try a mini split for the garage next. Thos may go on my back patio and likely angled a little for that Afternoon sun.
@@hackfreehvac I used to live out there. The HOA can be brutal . I now live in a hole in the woods with no neighbors. Love it! Please keep us updated on the project and results on the electric bill.
@@bryansimon4072 I kinda wish I could get some property up north in the mountains and start building something off grid.
@@hackfreehvac once you do that you you’ll wonder why you didn’t do it to begin with. I live in eastern NC 20miles out of town on acreage with no neighbors. Quiet. All the work I want and peace when I want it, except for my wife of course 😂. Wish I’d been in Hvac when I lived in Phoenix. Hindsight I probably would’ve stayed. The
where’s the rectifier? got basic schematic for the whole thing? solar + grid + dc bus? and cool man (literally)!
Variable Frequency Drives have the rectifier inside.
You connect AC voltage right to them (ordered for 230V or 460V 3 phase motors typically).
And some have DC Bus connections on them so you can supply DC right to the capacitors.
Working on VFD's on commercial HVAC is what gave me the idea to just skip the typical solar panels + charge controller + inverter (single phase) that is typically purchased. 😆
With the VFD in just feeding the utility power into the AC input (how they are typically used) but then connect my solar DC to the Bus after the rectifier.
When then solar voltage is higher the AC input simply shuts off because the diodes don't switch on when the input is less.
The transformer knocked my utility power voltage down a few volts to keep it under where the solar is during sun exposure.
It worked so I just kept refining it.
Much of the parts were parts I acquired.
So I don't have much in it.
@@hackfreehvac thanks for the info! very cool. i figured it may have been that simple, but devils in the details!
i’ve played with some of the ABB VFD’s in my building at work but didn’t realize there was a way to do both AC & DC inputs on some of them.
taught myself how to control the ABB’s recently; wound up installing a Click PLC and using the PID loop to drive the blower motor to keep static pressure more constant throughout the day. then added a pneumatic transducer to drive the chilled water valve. I’m controlling my roof AHU’s fan wall / valve via bacNet with some python scripts i wrote. fun stuff, but not as fun as high voltage DC experiments! lol.
it’s all temporary as we’re installing all new ddc controls throughout the building (Delta), getting a new air handler and a new air cooled chiller (the permit was finally approved on Friday!!). Fun HVAC times ahead!
thanks for your vids! keep up the good work.
@@princesswalt4010 nice 👌
Can I ask total newbie looking to buy an install the growatt 3000, mmpt, solar linked to breaker box etc.
Wat does this transformer do and why is it so important?
Any links be great
I was wiring high voltage direct to the heat pump 3 phase VFD in this case.
No solar charger/ inverter. Just two sets of 11 panels in series for 330VDC
I used that transformer to slightly lower my utility voltage from almost 250vac (over 330VDC rectified)down to something like 220 so that when the solar voltage was higher it would draw from the solar
Higher solar DC voltage meant that the diodes from the lower AC supply didn't turn on as a way to automatically switch over from utility to solar.
It was an out of the box experiment.
I am more using a solar charger inverter and connected to the water heater and batteries instead
Good video ! That’s a Cool set up u got there now. How Many Panels are u using ?
22 panels.
30VDC 250 watts each.
I have two 11 panel arrays wired in series to get the 330VDC.
I wonder if heavier gauge wire from the panels will stop the slight trickle from utility when the VFD is at 60hz
You mean that slight fan speed oscillation we heard?
That is the electronic fan motor for the condenser. Runs separate form the VFD.
IT only did it a few times and usually when I abruptly pull the disconnect etc.
I haven't noticed it before that or any other time it is running so I am not worried about it.
@@hackfreehvac no, the trickle of amperage from utility that occurs when at 60hz
@@CraigDohner
Oh. The panels just can't power it at 60Hz except at high sun. Like noon until maybe 2 it might. Then it can't.
It's been handling 40Hz (1st stage) until at least 4:30 though.
Wouldn’t it be Better to Have the Solar Panels hooked to a Battery 🔋 Bank and Pull Off to Several inverters. That Way You can Keep adding Solar Panels till the Cows come home !
Dude, that is so dope!
Did you just get the inverter from a broken variable unit or is it a commercial VFD?
VFD.
They were new but never used from a change out a few years ago that had the wrong voltage VFD's installed.
They sat in a warehouse for a year or so. Someone there knew I'd take them. :-D
Fluke, Trane’s and Toyota’s..... LMAO