I hope that someone may be able to help me with a problem i have-
My good lady wife dusted down her trusty Kenwood mixer last night to get started on the Christmas cake (apparently it must be done this weekend or doom will ensue)
On attempting to use it she found that when switched on the motor would start then stop then slowly start etc etc- generally misbehave.
Here is a short video of the misbehaving motor:
I stripped the beast and checked the brushes- all ok and so took further advise from a "kenwood expert" who says my speed control is likely goosed (a common problem it seems).
He recommended replacing the triac, a couple of 4.7k resistors, a 220uF capacitor and a 150nF resistor.
Although i can't see any obvious signs of distress on the board such as blown / leaking cap's or charred resistors i am not capable of testing the triac with the limited equipment i have so thought it best to go ahead and replace the components suggested by "the Kenwood man"
The control board is actuated by a rotary dial – the spindle passes through the board and the speed control (Potentiometer?) we have a direct mains voltage input, a motor output and a thermistor input (thermistor is attached to the motor to prevent overheat)
Upon turning the dial the motor speed should increase progressively depending on dial position- The machine also has a function whereby you can turn the dial in the opposite direction for a "pulse" of full power- this full power is applied until you release the dial and it returns to 0 (stop) via some sort of spring action in the potentiometer?
I only have a Maplin in my area and can't seem to find a like for like match on the capacitor which should be a 150nF 275v x2
The only available 150nF capacitor at Maplin is a Wima Polypropylene Metal Foil 1250V 0.15uF Capacitor which is obviously 4.5 x the voltage of the one i want to replace, other than that the closest match i can come up with at Maplin is a 0.1uF 275V X2 RFI Metallised Polypropylene Capacitor.
Can anyone tell me if either of these two capacitors are likely to be acceptable?
I thank everyone in advance for their time, i'm sure you all get fed up with people like me popping up out of nowhere asking for help but it really is appreciated!
Regards,
Rob
Best Answer
The precise value of an RFI suppression capacitor like that is not terribly critical, so using a 100nF X2 cap instead of a 150nF one should get the circuit up and running for now at least. You can order the 150nF/275V X2 cap from most mail-order suppliers though -- I'd try Farnell, given where you're at.