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Motorun Phase Converter rated to 8Hp, can it run a single 7.5hp motor?

pxr5

Plastic
Joined
Dec 4, 2019
Ive been offered a Motorun phase converter, it has a dial to switch from 1,1/4hp to 2,1/4 HP another at 1hp to 1,1/4hp, another at 5hp to 6hp, and then the last one at 7hp to 8hp, question is will it power a single 7.5hp motor? or is it only for two to three motors at the upper (last) power setting? thanks
 
I suspect that switch just optimizes balancing for different size loads. Is there not a max rating on that unit?

Per their website: When selecting a Rotary converter, the largest motor to be used should not exceed 50% of the Converter capacity, i.e. For the 20 HP unit the largest single motor should not exceed 10 HP. Smaller motors can be run simultaneously up to 20 HP.

They have a website with phone numbers. Just call them. You are both in the UK.
 
Well that name is a blast from the past. Not the original Motorun company based in Teddington who made the one I had but assuming its all basically the same circuit you appear to have a static phase converter that will run a single motor of up to 8 hp.

Mine was well made where it counted.

The switches set the balancing capacitor bank size needed to get a reasonable approximation to three phase out of the device and, probably, also adjust the start-up boost bank.

If there is just a single dial then it should be set to the range closest to the motor rated power. If it has multiple switches, like my old one did, you need the correct combination. The instructions I had being spectacularly confusing.

You really need to talk to the company as getting the settings wrong will have bad effects.

Mine worked a whole lot better when I stuck a big old motor somewhat larger than the nominal rating on effectively making it into a rotary converter able to drive a motor of its nominal output power rating providing the start load wasn't too high. So no compressors.

On a side note looking at the Motorun web site their rotary converters are seriously de-rated relative to the nominal output suggesting that the rotary element is both undersized for the job and that an ordinary motor rather than the proper designed for the job device. This seems to be normal practice these days. Probably to keep the cost within bounds, but it isa trap for the unwary.

Clive
 








 
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