It might be a lot cheaper to buy a 4 pole motor and just run it slower from the inverter, or even change the pulley size on the motor.

Running it slower would reduce the airflow through the motor? The pulley option may be a better solution…..

As for slow starting, vfd's I have used have a start up ramp that can be changed……I guess it depends on what is meant by 'slow start' ?

The other pulley could be made larger. The 6 pole motor is going to cost a good bit more than a 4 pole, even if you have to put a jack shaft in to get the speed down.

Ian S C

I couldn't get anything in writing of the makers but I went through this with the motor on my lathe. I fitted 6 pole to reduce the revs and then ran the inverter at a frequency to get the same rpm as a 4 pole. Most motors are rated to run at 60Hz anyway so that's part way there. You might find something like inverter frequencies from 40 to 80hz are adequate most of the time. I don't see much risk of overheating etc even with long running times under heavy loads. I did as many do uprate the motor HP though. Fitting a 1HP to an ME10 was rather tight. Had to use high tensile M4 in places. In real terms I suspect 3/4hp would have been adequate.

This makes more sense to me as it retains torque more when the speed is reduced.

John

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Rik,

Guess what sort of fan belt they are using on bulldozers these days

https://xtboshuo.en.alibaba.com/product/60556759927-800852639/3040292_engine_parts_fan_belt_poly_belt_for_bulldozer_fan_and_water_pump.html

MichaelG.

Edited By Michael Gilligan on 15/11/2016 19:48:24

Sorry if I have misunderstood your requirements, Rik

Mine was a serious suggestion, made in response to your comment that further reduction of the motor pulley diameter was 'ruled out'. A poly-vee belt capable of transmitting one horsepower would probably run comfortably on a one inch diameter pulley [which a chunky vee belt will not]

… I will leave you to it.

MichaelG.