Controlling Motor Speed

You cannot use a 3 phase VFD on a 1 phase motor.

There are a few VFDs that are designed to work with only 2 types of 1 phase motors, specifically PSC (Permenent Split capacitor) and Shaded Pole. You cannot vary the speed of any other type of 1 phase motor.

Invertek (UK) is one of the few who make such a VFD. There are several other brands marketed, but most are just brand-labeling the Invertek drive.

An alternative is to replace the motor with a 3 phase equivalent, then use a 3 phase VFD that will accept a 1 phase input, These are very common and available from all of the major manufacturers.

You can use a variable gear for manual control, for autocontrol (closed loop with feed back) you have to options :

1) If 3Ø source is available you can go for 3Ø motor with VFD

2) If 3Ø source is not available you can go for DC motor with AC/DC convertor with conroller.

Good Morning Chaps,

What will you use to control the motor speed input, temperature, pressure, air flow?

For temperature there are many air conditioning fan speed controls on the market at relativley low cost that can utilise either input. Sagamaya units are single or three phase and cost in the regeon of 50-80 £sterling

KB Electronics makes an inexpensive fan controller.

Click http://www.kbelectronics.com/catalog_fan_dist_chassis.htm

Regards, Delmar Schmidt
Melfi Technologies Houston
www.melfitechnologies.com

check out 'Lutron` fan controllers.

What size is the motor (kw) as there are plenty of manufacturers I can advise you about.

I use small fan (100-200W) to cool down machine

Westmid Fans on telephone No +44 (0)1215500315

Model No WMF3 (3Amp) WMF or WMF6 (6Amp) should be ok for your application.

or Woods Fans on +44 (0)1206 544122 Model Type MFE1+current rating required

or Roof Units on +44 (0)1384 418670 Type SP5010 (1amp) or SP5025 (3amp)

I have installed all the above equipment ok.

I also have the circuit diagrams to manufacture a simple 3 component controller at other office. I could fax to you if you want as I have no (working) scanner here.