Rotary Convertor Pilot Motors

With no high starting torque loads 2 Hp will be fine. Jim

Pppppssssstttttt, Wanna buy a motor ????????

-- Regards,

John Stevenson Nottingham, England.

Ere! get in the bl**ding queue!! :-))

Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

My 7.5 kW pilot motor works fine with my 7.5 kW lath motor, but to help thing along I wired in an extra capacitor bank with the lath motor, as this saves having to re set the converter.

Luckily since this is a 415volt application I think that I have a suitable motor for a change.

Sorry if the cynical traders will have to go without this Christmas.

Charles

Humbug.

-- Regards,

John Stevenson Nottingham, England.

Shame on you, Charles, getting our hopes up like that! :-))

Peter

I would have thought (not that I can claim much experiance of this) that the pilot motor could have been the same size or possibly slightly smaller than the load motor.

Ater all power from at least one of the 3 phases would come direct from the mains (i.e only 2/3 of the power will go through the pilot) - and conversion efficencies of commercial units seem to be well above

Steve

That does lead me ask what the fundemental differences are between commercial static and commercial rotary pahse convertors. The price premium of the rotary seems one hell of a hike for a new motor alone when most of us are very happy with second hand motors in most situations. Should people just buy a static convertor and bolt on a no load pilot?

Charles

I was under the impression that's all they were. Perhaps Jim can chime in here and give us a valid opinion on the differences.?

-- Regards,

John Stevenson Nottingham, England.

This is correct and I would take it a stage further.

Try the static converter only solution first to see if you have any problems. If you're short of starting torque or if you need to switch in different load motor combinations then add a pilot to dilute the load variation seen by the static converter.

This comment applies to reputable UK or home brew static converters which include both starting AND run capacitors.

In American practice the term "static converter" is also used to describe buzz boxes which only contain starting capacitors. With these boxes, unless the load motor is substantially derated, a pilot motor is essential.

The static converter only solution will always be short of starting torque but load motor maximum power output is very unlikely to be a problem.

Jim

Thanks Jim. Definitive as ever.

Charles