Logik L612WM13 not behaving after brush replacement

[ldeevans]

Hi, Our Logik L612WM13 stopped after a main wash with E60. I checked the motor and found that the brushes were virtually gone, so ordered and fitted new ones.  Now the motor runs, but it is unable to complete a wash, seemingly unable to get to full spin speed, sometimes reporting E12, but mostly trying to get to full speed (speeding up and slowing down).  When it seems to get to the point of full spin speed (it's going quite fast at this point, at around 9 mins to go) the machine shudders, there is an odd knocking/whooshing sound, then it slows, eventually going straight to 1min left.  Sometimes it just sits there (at 12 mins) seemingly stuck trying to empty, but this may be due to our not loading it enough.

As per your excellent FAQ, I have tested the pressure switch by blowing into it, it clicks, and testing with a meter seems OK.  The pipe is also unobstructed down to the pump at the base of the drum.  I don't know a great deal about motors (synchronous?) but did a resistance check across the disconnected brushes and all segments were around 3.5 to 4.5 ohms, no opens/shorts, thinking that maybe a field coil has burned out.

The suspension seems fine, the belt OK and the spider intact.  Seems strange to me that if there is a fault unrelated to the motor, that it should occur at the same time, but that is just my usual sort of luck 😁

Any ideas please, the machine is about 7 years old now, the bearing still OK, so potentially some life left it it.

Hope you can help,

Cheers, Dave.

 

Edited March 6, 2021 by ldeevans

[Whitegoodshelp (Andy)]

Is the motor sparking excessively when it tries to spin? 

[ldeevans]

Hi Andy, thanks for replying. Raised the machine off the ground using two fence posts, and used a mirror.  Not sure how much sparking I should see, but there is some when just turning slowly, and lots more (even red flashes) when trying to get to high speed.  In the dark it was quite a show!  After two attempts at this the machine then (strangely) stopped with E12 (water level) again.  Does this mean the motor is kaput?  If so, do you know why it should go when the original fault (appeared to be) the brushes?  The price of a new motor on-line is more than twice what I paid for the machine in the first place, so maybe it would make more sense to get another machine.  Thanks again for replying.

Edited March 7, 2021 by ldeevans
Shouldn't mention specific online service

[Whitegoodshelp (Andy)]

Yes unfortunately motors are very expensive these days. If you fit new brushes and the motor is still sparking and struggling to run smoothly or maintain speed then either the brushes have not bedded in, not been fitted the right way round (which theoretically can happen), or maybe the armature that the brushes run on is too badly worn.

If by any chance the brushes were fitted the wrong way round they would make quite a loud clatter to sound like an old football rattle. I have an article here about this problem which you should check out Fitted new carbon brushes but the motor is sparking now

[ldeevans]

Hi Andy, after reading about the sparking brushes as per your link, that got me thinking.  I remember the brushes not wearing over the whole profile, just about a millimetre on one edge, and that the profile was not as steep as the old brushes.  So, having nothing to lose, carefully filed the profile to match the old ones.  Now the machine works as before, and the missus isn't going to leave 😁.  Many thanks, much appreciate your help.