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220V Euro Inverter to power 240V US compressor/air conditioner

n4mwd

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Aug 15, 2020
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I know you aren't supposed to do it, but if I have a 240V A/C unit that uses split phase US 240V and does not use the neutral wire, can I power the A/C compressor with a 230V single phase Euro inverter.

The reason I ask is that 230V Euro inverters are a tad cheaper than US split phase inverters of the same power. If I dedicate it to the appliance, it shouldn't be a problem as long as it works.

Has anyone tried it? And did it work?
 
I've wondered the same. One thing for certain is the Euro spec inverter needs to be 60Hz instead of euro 50Hz.

One thing that gives me pause is that on a mini-split system, the blower side of the unit REQUIRED 120VAC with L1 and N, so I would confirm that the entire unit including the air handler is truly 240VAC exclusively.
 
I've wondered the same. One thing for certain is the Euro spec inverter needs to be 60Hz instead of euro 50Hz.

One thing that gives me pause is that on a mini-split system, the blower side of the unit REQUIRED 120VAC with L1 and N, so I would confirm that the entire unit including the air handler is truly 240VAC exclusively.
Some Euro inverters have a 50/60 hz switch of some kind. That should take care of the frequency issue. What I'm proposing would only work on 240V split phase motors that don't use neutral. So you would connect the neutral and hot wires from the euro inverter to the L1 and L2 of the 240V motor. In theory, it should work, but it wont work for anything that uses 120V.

I was wondering if anybody has tried it and what the result was.
 
It should work if the appliance doesn't also have 120 (e.g. stoves use 240 for heating elements but 120 for circuitry ... but you won't necessarily know that). If the device doesn't have a neutral connection, you're fine. If it does and you don't connect it and it uses it, you can cause damage.

An autotransformer like the ones Victron sell are a good way to create 120/240 split phase from 240 and is even a design pattern they suggest (e.g. use a euro 10kva victron, set to 60hz, add an autotransformer, and now you have 10kva of 120/240 split phase with the added bonus of balancing the power between L1 and L2)
 
It should work if the appliance doesn't also have 120 (e.g. stoves use 240 for heating elements but 120 for circuitry ... but you won't necessarily know that). If the device doesn't have a neutral connection, you're fine. If it does and you don't connect it and it uses it, you can cause damage.

An autotransformer like the ones Victron sell are a good way to create 120/240 split phase from 240 and is even a design pattern they suggest (e.g. use a euro 10kva victron, set to 60hz, add an autotransformer, and now you have 10kva of 120/240 split phase with the added bonus of balancing the power between L1 and L2)

Yes, stoves are bad that way. Many have 120V taps for clocks and electronics. They would require modification to run without the neutral. Probably just change out the power supply transformer to a 230V one instead of 120V.

In my case, I have an A/C outdoor condenser that uses about 4KW run / 12KW start with no 120V circuitry at all. I want to be able to power it and a subpanel from batteries as backup. Since a split phase inverter is almost always more expensive, I wanted to get a euro 230V inverter to use with just this load.

Since the main inverter is more expensive per watt because it does grid tie and mppt and battery charging, it makes sense to separate the loads.
 
Not that I need to, but I checked the wiring diagram for my own oven and to convert it to 220V euro would require a new 220V power supply for the electronics and some way to power a 120V light bulb. Right now, it uses a 120V transformer so replacing it shouldn't be that hard, or a bigger 220V to 120V transformer that could power the bulb as well. A modified travel voltage converter would probably work.
 
I also would like to operate my 2 HVAC units that are both pure 240v loads and dont even have neutral wires providing power to them with 2 paralleled MPP MG5000 s that I have been using just to charge extra battery banks. About half the cost and less than half the size /weight of comparable 240 split phase units. The other advantage is they take high pv input voltage though affordable split phase units are becoming increasingly available now and even units that blend solar and grid power. This would offset about 70% or more of my electric bill and enable me to use a much smaller single inverter rather than 2 or up to 4 split phase inverters for the whole house. In this manner I will only need 1 split phase inverter for the remainder of the house.
Hopefully someone can answer this question directly. I think I have already received a round about answer to this and it will work but hate to do it at least on HVAC unit without confirmation at this point. Guess I could try it on a 240 volt 5 hp air compressor motor I have first to limit any possible loss. I believe they are capable of 60 Hz .
 
I found the image below which illustrates how 240 volts work in split phase systems. The black phase, which would be the same as Euro 240 single phase, is what you get when you subtract Phase 2 from Phase 1. There could be a problem if the inverter ties the Euro neutral to ground. So the bottom line is that on paper a Euro inverter should be able to power a US 220vac HVAC condenser. It would probably work at 50Hz, but most euro inverters can do 60Hz as well which would be better.

1623628661016.jpeg
 
Did it work?
I haven't heard anyone saying they tried it, but several other people I asked said that it should work. So basically, I still don't know for sure. I have been busy and haven't had a chance to buy one and test it myself.
 
After asking here, I also asked Ian from Watts247.com and apparently yes, it works. He mentions how to wire it here. "In the USA, L1 will need to be connected to the N (Neutral) Input, and L2 will need to be conencted to L (Live) input, in order to input 240V into the inverter. The output Terminals (N & L) will essentially output 230VAC"

I saw elsewhere that if your mini-split runs 220V only (no 110V components, and no neutral) it should work:
"There is some equipment that is referred to as 240V, that still uses a neutral line because some of the internal parts use 120V.Such as a clothes dryer or oven. You can verify what you need, by looking at the installation manual for your mini-split, or the schematic sticker you can usually find when you remove a cover. There was another thread here a short while back that made it sound like residential AC typically does not use the neutral. But I can attest there are roof tops and other equipment out there that use 240V or 208V but still use 120v for a fan or timer or whatnot, which means they use a neutral..It is not uncommon to find added equipment or after market equipment on these systems that need the neutral too."

I take no responsibility for this information. If you do this and your AC breaks in half, you get to keep both pieces.
 
After asking here, I also asked Ian from Watts247.com and apparently yes, it works. He mentions how to wire it here. "In the USA, L1 will need to be connected to the N (Neutral) Input, and L2 will need to be conencted to L (Live) input, in order to input 240V into the inverter. The output Terminals (N & L) will essentially output 230VAC"

I saw elsewhere that if your mini-split runs 220V only (no 110V components, and no neutral) it should work:
"There is some equipment that is referred to as 240V, that still uses a neutral line because some of the internal parts use 120V.Such as a clothes dryer or oven. You can verify what you need, by looking at the installation manual for your mini-split, or the schematic sticker you can usually find when you remove a cover. There was another thread here a short while back that made it sound like residential AC typically does not use the neutral. But I can attest there are roof tops and other equipment out there that use 240V or 208V but still use 120v for a fan or timer or whatnot, which means they use a neutral..It is not uncommon to find added equipment or after market equipment on these systems that need the neutral too."

I take no responsibility for this information. If you do this and your AC breaks in half, you get to keep both pieces.
Thanks for the update. My outdoor condensor definitely does not use a neutral. I'll look into getting a euro inverter for it.
 
Basically I would say that if there is no neutral wire even going to the HVAC then you should be ok to wire it as explained.
Some split units (not meaning mini splits) use 240v for outdoor condenser and 120 for the indoor unit fan etc.
 
In my case, there is definitely no neutral wire going to the outdoor condenser. I don't know for sure about the evaporator. The evaporator has electronics in it that might be pulling from the 120 leg. However, it only uses about 5-600 watts going full till. Not counting the 10KW heat strip. I need to rewire it because I want the wire for the heat strip separated from the wire for the fan and electronics. Tht makes the inverters more manageable.
 
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