Voltage Doubler (115 to 230V)

[dkfullerton]

Please Help if you can:

I have an AC Drive that I use as a demo at trade shows and in front of customers. I am travelling with a 15lb step up transformer. I had an aquaintance tell me that I should build a Voltage Doubler (Full Wave Rectifier) Circuit. The drive is 1/2HP, 230V, 3.5Amp unit. I will drive a motor with no load attached. The current requirement will be quite low. Thank you for any thoughts or guidance that you can offer.

Doug

 

[technogeek]

Depends on what you need... a voltage doubler will output DC. If you need AC for your motor, it won't work.

 

[RadioRon]

I was wondering about the idea of using a 115V to 12V switching supply feeding a voltage inverter designed to deliver 230V. Like cascading one switcher with another. This could potentially be lightweight, but I haven't done this before and if it must have a 12V battery between to smooth out the voltage, then the weight may still be a few lbs.

While searching, I came across this vendor https://www.voltageconverters.com/index.html
who has 12V to 220V inverters designed for 50Hz operation so I was wondering if your motor drive can stand 50Hz? I also noticed that they have a line of step-up transformers that are at least somewhat lighter than what you use now. For example, the 500 W model, which might be enough to get your motor going is here:

http://www.voltageconverters.com/itemdesc.asp?CartId={60C8DB51-B1F1-49EVEREST87-9B26-550B9DC5D5D4}&ic=VC500W

Beware that motors normally require a high inrush current for starting. In your case if you are running without a load, the inrush might not be too bad, but with my little experience I can't esitimate it other than to guess that it might be 10 times the steady state load. If your motor is pulling, say one fifth of its full load current when unloaded, that would make the steady state about 150 watts, but then the inrush may be five times that, around 750 watts?? I don't know for sure. Anyone else?

 

[Nigel Goodwin]

Please Help if you can:

I have an AC Drive that I use as a demo at trade shows and in front of customers. I am travelling with a 15lb step up transformer. I had an aquaintance tell me that I should build a Voltage Doubler (Full Wave Rectifier) Circuit. The drive is 1/2HP, 230V, 3.5Amp unit. I will drive a motor with no load attached. The current requirement will be quite low. Thank you for any thoughts or guidance that you can offer.

A transformer is cheap, reliable, and VERY effective - as you say though, the weight is a problem.

As others have said, a voltage doubler outputs DC, and for such a high power would be large and fairly expensive (big capacitors).

Personally I would suggest sticking with the transformer!.

 

[stevez]

Doug - just wondering if the drive is what you are trying to demonstrate. If it is not, can you purchase a drive that can be wired for one voltage or the other on the input? A friend of mine is in that business and tells me that some of his products are quite versatile.

 

[Hero999]

Don't you have some 230V sockets for cooker/aircon/heater sockets?

If you can wire it hot to hot then you won't need a transformer or doubler.

Also, if you add a power factor correction capacitor would could bring the currenct down significantly so you could use much a smaller transformer, possibly half the size what are you using now, a 1000VA unit? With power factor correction you could use a 500VA unit instead.

 

[JimB]

If you can measure the current taken by the drive under the conditions you will be using (no load) then calculate the VA.
Select an auto-transformer rather than an isolating transformer, with a rating compatible with your drives VA demand, so you are using the minimum size transformer.

Auto transformers are usually significantly lighter than the equivalent isolating transformer.

JimB