we are doing a project on controlling the speed of a single phase shaded pole ac induction motor. we want to know how speed is related to the voltage applied to the motor. we dont have any algorithms for this. can anyone please help?

warm regards,

tony

 

The links below show what a shaded pole motor is, how they operate and showing that frequency not voltage is the independant variable.

http://elpaso.apogee.net/md/mfmssha.asp

http://search.globalspec.com/goto/PDFViewer?pdfURL=http://www.fasco.com/pdf3/page05-06.pdf

 

Thanks a lot for the help. But sir do You have any idea about any site or tutorials giving an alogithm saying how to control. I mean a step by step procedure.

Warm regards,
Tony

 

Since it doesn't have a capacitor, you can run it from a VFD if you are very careful with the V/Hz setting and voltage range (overheating etc.) as SP motor is not like the industry standard 3-phase induction motor with mostly linear v/hz. Also, if the drive bus voltage corresponds to > motor ac rating, the life may be reduced. It will also have limited useful speed range. I did a SP motor application years ago when I worked for a drive mfg. Other reply is correct too, freq largely determines speed, voltage determines slip or torque-speed curve stifness.

 

<p>Motor voltage is V and frequency is F
<pre>
V/F=C C constant.

For example

Veff = 266V F=60Hz n=1200 rpm
Veff = 220V F=50Hz n=1000 rpm (Normal condition)
Veff = 176V F=40Hz n= 800 rpm
</pre>

 

Is this shaded pole torque/speed can be controlled using PIC? Depending on the torque required we have to maintain the current. For that can we use PIC to control v/f accordingly so that current will be maintained to required value?

Regards,
GP