Rotary phase converter for screw compressor. Options?

[flanajb]

Hi,

Having ruled out a piston compressor due to the associated noise, I have decided that a 5.5hp (4kw) screw compressor (60db) is the way to go. Trouble is, the unit will have to be 3 phase and I will need to source an appropriate phase converter. From what I read, a static convertor is not suitable and I will have to go with a rotary phase one.

If anyone in the know can answer the following I would be most grateful

1) Is it true that if the compressor has a 5.5hp motor then I need to go for a converter that is double in size eg 11hp. Would a 10hp suffice?
2) Having looked at ebay one of these will cost in excess of 1k. Are there other options to bring the price down?

Many thanks

 

[flh801978]

Compressors are really difficult to start at the best of times
If you only have a single phase supply then in reality you are stuck with single phase motors ( get 2 motors/pumps on one tank if you need lots of capacity)
Inverter could do it if the motor is dual voltage and you have a big supply 30-40 amp and deep pockets for that £ 500 ish but big rewiring job

before buying a phase converter check that it will work ( see it working ) for a compressor they really are hard to start
buy both compressor and phase converter from same source...check that it will work

it will be starting regularly when in use

 

[nathandavies]

I bought a big un from these guys

http://www.powercapacitors.co.uk/products/transwave-converters/

Give them a call, they'll help you with whatever you need, and won't push a bigger than you need unit on you.

If this is your entrance into three phase, you do realise that you will be opening up a whole new world of tools to be had (from the bay for me) and you may well want the capacity in the future.

They produce several different power models but I think 3 or 4 physical size cases for the rotary. What they said to me was to get the correct size for now, and in my case that left me with room in the housing to upgrade in the future should I need to. They can take my unit back and upgrade it for the same amount of money as the difference originally.

As I said I have found them very helpful.

HTH

Nathan