Hello all,
I have a gas generator that produces 110v AC. I would like to hook it up to a piece of equipment that runs on 220. With standard house wiring you simply hook up two out-of-phase (L1 and L2 from the street) 110 lines to the 220 outlet. The generator has several 110 outputs but they are all the same phase.
My question: Can I simply use a phase-shifting capacitor on one 110 line to get two phases for the 220 hookup?
TIA
I think a 1:2 stepup transformer would be easier, as long as it's rated for the current you are going to load it with.
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Might want to give a closer inspection of the wiring for your generator. Most alternators produce 220 and put the 110 outlets on the seperate phases.
Actually, if your talking US systems, your voltages are 120 and 208. The conversion of voltages with respect to phase-to-phase and phase to neutral is root3 or 1.732 ie 120x1.732 = 208volts phase-to-phase
A "phase shifting" capacitor is the same as a piece of string (how long) The phase shift depends upon the capacitor value and the load on the end of the capacitor and it certainly will not increase the voltage above your current generated voltage. If your genny really is outputting 110 and you want 220 then a 2:1 transformer working in reverse might do your job. mathematically it will do what you want but the low impedance of the 110 winding might not match the generators ability to accept the inrush current.
jack
I think a 1:2 stepup transformer would be easier fr your generator..
You can't even phase shift 90% with a RC network. And you don't want to... A 1:2 step-up transformer or auto-transformer will do the job.
Thanks to everyone for the replies.
I know that a transformer would work, but I am intrigued by the idea of using a capacitor, and why it would or would not work.
Just in case there was any confusion as to what I was asking I want to know if this is possible:
[ Generator ]
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110 110
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| Capacitor
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\ /
220
Is this not what a motor run capacitor does?
I have lots yet to learn...
Thanks!
Your diagram misses out the load. This may be resistive, inductive or non-linear like a PSU. The load impedance will be different for different loads, the capacitors impedance is constant. You can do the calculations if you are OK with phasor diagrams.
You can't get 180 degrees phase shift from a capacitor so you would not get the voltage you want. Also the capacitors would have to be rated to take a ripple current that matches your motor's current, that would make them big and expensive.
So in theory a capacitor could work, but the devil is in the details, and practically a transformer would be a better approach.
Thank you all for your input.
So in theory a capacitor could work
You can only get 90 degree shift from a single capacitor so in practice you will need three caps and resistors to get the phase shift you need (180 degrees). That would give you two out of phase voltages. BUT the load would have to be resistive to prevent the phase being buggered about with.
practically a transformer would be a better approach.
Yes that's it. 
jackrae:
Actually, if your talking US systems, your voltages are 120 and 208. The conversion of voltages with respect to phase-to-phase and phase to neutral is root3 or 1.732 ie 120x1.732 = 208volts phase-to-phase
220 or 208 depends on if your talking single or 3 phase power in the US. 220v is actually 240v. the lower voltages are depreciated standards. Most homes and very small industrial are single phase 120/240. Industrial and large retail are mostly 480/277 AND 208/120 3phase. The vast majority of the US does not have 3 phase available to the end user unless your in an industrial area.
To the OP, the answer depends on what your trying to run. There are ways but they tend to be current limited or cost prohibitive. Look up voltage doubler. They tend to produce DC with a high ripple. What are you trying to do?
What are you trying to do?
Trying to run a water pump during power cuts.
Pokey:
What are you trying to do?
Trying to run a water pump during power cuts.
No way your going to get that running well using a cap, diode, or voltage coupler.
First check if the pump can be rewired for 120. In many cases it is simple as moving 1 or 2 wires. If it is a sealed or single voltage only pump you are going to need a transformer big enough to run it. For the cost you MAY be better off buying a different pump or generator. It all depends on what you have to work with and what you can find. Post some more details!