Extractor motor controller advice

[simonwig]

Hi

Looking for advice from anyone with electrical engineering knowledge.

I dusted my extractor off today for an extraction, and the variable speed isn’t varying.

Basically the motor is either on or off, changing the dial has no impact. My sense is it is at a speed between slowest and fastest, but no way to prove this.

There’s no obvious damage to any of the cables/wires.

First question is do I assume it is the speed controller, or might it be the motor?

If it is likely to be the controller, is there a simple way to test that?

Or indeed if it’s thought it might be the motor, any simple way to test that?

I have a multi meter but not sure what I’d be checking.

I’ve attached photo of the control unit wiring and wiring diagram (although it looks to me that there are only two wires actually going to the motor).

A photo of the control wiring (as printed on the controller), wiring connection to the controller, controller front, and motor specification attached.






Any advice or pointers much appreciated or if anymore info would help let me know.

If a replacement controller is suggested, again any pointers appreciated.

The extractor is about 8 years old but I can’t find the original details or make from when I bought it

Thanks

Simon

 

[viridens]

I am not familiar with that controller, but the fact that your motor runs at a steady speed indicates that the controller has a fault. Leeds is too far for me to call round with my soldering iron etc., so a replacement is your best bet. There are plenty on ebay which may be suitable.
There should be a rating plate on the motor giving voltage / current / speed information as a starting point.

P..S. Afterthought. Check that the knob is actually doing something and hits a stop at both ends of the scale, and is not just loose on the shaft.

 

[Bryang]

Could be that the control knob has worked loose.. Older types of electric motors worked by varying the resistance in series with the motor, high R motor is slow... low R motor goes faster.. Just a thought. Looking at the very basic Cct diagram (Wiring) of the motor it suggests that the motor speed control is "stepped", which in itself suggests that . SO if the motor is running at a constant speed either the knob has come loose or the "shaft" that the knob is fixed to has broken.

 

[Anduril]

If you open up the speed controller and it is the potentiometer at fault and you need further advice on a replacement, I recommend this forum for help Electronics Forum (Circuits, Projects and Microcontrollers)

 

[simonwig]

Thanks, appreciate the responses.

The knob is turning smoothly with some usual resistance, and starting the spin, so I don't think it's that.

Given the relatively low cost and what look like the same / similar model on ebay etc I'll give viridens suggestion a go and swap it out.

Simon

 

[viridens]

Send me a pm if you need help.

 

[simonwig]

Send me a pm if you need help.

Thanks, appreciate the offer.
Simon

 

[frankenstine]

Sounds like something has given up. Chances are is a basic crude speed controll and thyristor in it has poped if the unit is avalible economically I’d just replace it rather than investigate

 

[simonwig]

Thanks again
Replacement controller sourced, ordered, received, fitted, problem fixed.
Simon

 

[fizzle]

It would have been the variable resistor (potentiometer). You could test this with your multimeter by connecting the leads to either end of the pot and turning up and down. The resistance reading should change if working properly but in your case would have stayed at the same resistance.

Maplins would have been ideal to get a replacement pot but unfortunately they have gone bust.

 

[frankenstine]

It would have been the variable resistor (potentiometer). You could test this with your multimeter by connecting the leads to either end of the pot and turning up and down. The resistance reading should change if working properly but in your case would have stayed at the same resistance.

Maplins would have been ideal to get a replacement pot but unfortunately they have gone bust.

that used to be the case with well built kit but a lot of the Chinese stuff seems to be they don’t give much headroom on the drivers output stage, I’ve ripped off loads of pwm speed controllers with poped output stages