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Paddle mixer speed controller

Andy Twose

Feb 16, 2016
13
Joined
Feb 16, 2016
Messages
13
Hi,

I am tasked with repairing a Tecmix TM1100 paddle mixer. This is a 2 handled device used for mixed plaster and building materials.
The problem is that it runs at full speed.
I have remove the speed controller, which unfortunately is encapsulated in a hard resin.

As suspected the connections out to the motor are short circuit and these connections can be traced back to the large heat sink'd semiconductor device. I have called it that because therein lies my problem....it is not marked.
It is a TO220 package or similar.

I am guessing it is a Triac but would like confirmation of this, or suggestions of what else it might be.

Please see the attached image.

Only 2 slide connectors are connected to the motor, one is free and not used.
The 3 white cables go off to the handle to another PCB holding just the manual control which is a 500k pot.

The best I can work out for the component count on the encapsulated board appears to be :-

Small potentiometer
Single capacitor
2 x resistors
Triac or whatever it is
Something else, small, maybe a diode

Apologies for being so vague but the encapsulation is very black and very hard.
I do have access to the solder side of the PCB so it should be possible to sketch out the circuit.

It is conceivable that something else has blown, too, but I'll worry about that once I know what I am dealing with.

Any help appreciated.

Thanks
 

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Alec_t

Jul 7, 2015
3,587
Joined
Jul 7, 2015
Messages
3,587
Looks a likely circuit. D1 is a diac. C1 is a 0.1uF non-polarised cap.
 

Martaine2005

May 12, 2015
4,932
Joined
May 12, 2015
Messages
4,932
Hi Andy,
Have a look on the www for an inline motor rheostat. I have bought one and put an IEC connector for all my 110v tools. The IEC makes it similar to Festool, where one lead is needed for all tools!.
These motor controllers fail so often it's unbelievable they are still so popular. I am looking to do the same with my 240v tools. Just get the highest amperage you can to cover all tools. 15A is quite easy to find.
Your mixer will be under heavy load most of the time so a high amperage controller is important.
Keep us posted. You might find what I am looking for too.

Martin
 

Andy Twose

Feb 16, 2016
13
Joined
Feb 16, 2016
Messages
13
Thanks all.

Yes..I did wonder about an in-line controller...I will investigate.

Andy
 
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