Voltage Doubler for VFD

[Barry1961]

I am looking for a voltage doubler to replace a step up transformer to drive a VFD.

The specifications are 1/4hp, 230VAC, 3ph with a 115VAC, 60hz, 1ph supply voltage.

I would like to find something already packaged for panel mounting with MOV and over current protection. If I have to I can add protection.

For political reasons I can not buy a VFD with built in doubler and want something smaller than a transformer. I also don't want to mount exposed caps and diodes on a back pan.

My thought is to try and feed the doubled DC voltage into a single phase 230VAC VFD. I don't guess it would hurt to feed DC into a retifier.

I could overthrow the leaders and fix the political problem but I have a sore back.

Barry1961

 

[OperaHouse]

Many drives have the + & - from the internal cap available on terminals. If the unit doesn't have an internal transformer, this should work. Attach two 1,000uf or more caps in series to the +- terminals (w/ bleed resistors). connect the AC to one of the AC pins and the other to the center of the two caps. I've had a lot of luck running 3 phase drives on single phase. Your results may vary. Sounds like a bad idea unless this is a home project.

 

[jraef]

They are not hard to make, it's a very simple circuit. This web page shows one about 1/3 of the way down. I use the full wave version, but I know of a lot of micro VFDs that just use a 1/2 wave because the VFD has plenty of capacitance to smooth the ripple. Just make sure your VFD does not have input phase loss protection!

I have a premade one around here somewhere that came on a demo unit, but I have to dig through my storage closet to find it, and you aren't that lucky today.

"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more."
Nikola Tesla

 

[jraef]

Woops, forgot the link...

http://www.du.edu/~etuttle/electron/elect9.htm

"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more."
Nikola Tesla

 

[bklauba]

Take a look at KB Electronics inverters. There are units capable of taking your 120 s.p., and turning it into 240, 3 phase, with sufficient HP, and integral, adjustable O/L protection.

BK

 

[Barry1961]

I was hoping someone had already packaged the two caps, diodes and protection in some potting compond with a heat sink.

Barry1961

 

[Barry1961]

I found it. The key words I needed were "front end power supply". Seems like there are a few people that make them and they sell for about .09US/Watt.

Probably $45 for what I am looking at.

Thanks for the all the advice. Probably much better than what I will end up doing.

Here is a link to one of them.

http://www.vicr.com/products/ac-dc/rectified_filter_modules/offline_front_end/

Barry1961

 

[itsmoked]

BTW: Vicor is an amazing company. They didn't want to go offshore and they didn't want huge stock. So their entire production was automated and designed so each item is produced individually. Another words, every product coming down the line is different and automatically built.