Control Speed of AC Motor

marathont

Hi

I have an electric chimney cowl that helps the draft on my chimney when the wind is a certain way. This is a fan powered by an ac motor which is mounted on my chimney.

At the moment, I just plug it in when I went to use it, but I would like to be able the control the speed, so that I can turn it up or down.

Is there a suitable a controller I can buy to do this ?

Would something like this be suitable:http://www.ebay.ie/itm/High-torque-50V-220V-10A-AC-Motor-Speed-PWM-Controller-Power-2000W-13-KHz-/190958670955?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item2c7606146b

tomdempsey200

http://www.ebay.ie/itm/1-5-AMP-FAN-SPEED-CONTROLLER-ELECTRONIC-/221292465777?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item33860f0e71




i think the electronic are pwm

marathont

tomdempsey200 wrote: »

http://www.ebay.ie/itm/1-5-AMP-FAN-SPEED-CONTROLLER-ELECTRONIC-/221292465777?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item33860f0e71




i think the electronic are pwm

Thanks, what do you mean by pwm.

I wonder would local electrical suppliers stock something like that ?

2011

marathont wrote: »

Thanks, what do you mean by pwm.

Pulse Width Modulation.
PWM is used in variable speed drives (VSDs) in industrial installation so that the speed of a motor can be controlled by varying the frequency.

This unit may not be suitable for your application.

By studying the datasheet for both the motor and the controller it would be possible to see if they are suitably matched.

You could use a variac if it's non-electronic, but you'd have to be careful and set a minimum level on the variac when there's no wind. If you stall the motor while still running current through it you'll burn the motor coils. Fairly in-efficient way of doing things though. It'd be a good idea to check the spec of the motor for the voltage tolerance thresholds first too.

How does the motor prevent the wind running it as an un-kosher generator?

marathont

Sir Liamalot wrote: »

You could use a variac if it's non-electronic, but you'd have to be careful and set a minimum level on the variac when there's no wind. If you stall the motor while still running current through it you'll burn the motor coils. Fairly in-efficient way of doing things though. It'd be a good idea to check the spec of the motor for the voltage tolerance thresholds first too.

How does the motor prevent the wind running it as an un-kosher generator?

I dont know. I havent got access to specs for it. Is there a safe way to do this, without knowing much about the motor?

I saw the same unit on a website before (cant find it anymore), but it came with a controller.

I'd look for an online spec.
I'd be suspicious it's actually a DC motor stepped down, with diodes.
You could also see if it's written on the motor.

How many wires had the controller? Any pics?

You need to know a lot of things before you can do this.
Rated power + voltage thresholds.
Motor type and coil design.
Electronic or not....which kind of electronic.