Speed control of Induction motor.

[mooimooi]

Hi,

Would like anyone out there who could provide me
a circuit on to increase the rpm of the following
motor,
Brand name : Oriental Motors 6W, 230V, 50HZ, REV:120RPM.

I believe the speed can be controlled by changing
the frequency. I am operating this motor at 230VAC
50 HZ, and I am quite confident that if I add a frequency
converting circuit to the motor, speed control can be
effected.
Appreciate your inputs on this issue.

Thanks

 

[electricpete]

That is correct. It has been applied many times on industrial induction motors (known as variable speed drive).

However, as you decrease frequency, you should also decrease voltage proportionately to avoid increasing volts/hz (causes core overheating),

Increasing speed may require increasing voltage (may be risky if more than 20% increase) to avoid stall, and also may pose mechanical challenges to the motor and/or load. (centrifigual force is proportional to speed-squared).

Also, if your source produces harmonics or voltage spikes, those may be damaging to the motor (filtering may be required).

 

[mooimooi]

Hi,
Thank you for your valuble inputs. I would appreciate
if you could send in some circuits or appropriate websites
that deals in this subject.

Thanks
Chandran.

 

[electricpete]

Pick your favorite search engine and look for "variable speed drive"

 

[electricpete]

Here's an 81-page NEMA application guide on the subject.

There's a copyright notice in front, but it is available for downloading for the time being.

http://nema.org/engineering/icsstandards/acadjustable.pdf

 

[mooimooi]

Hi Electripete.
Thanks for your help
Chandra