capacitor in bosch drill

civ247

Hello,

I'm having some Problem with a Bosch electric drill (PSB 600 rpe)

When pulling the Trigger there was just a humm and the Motor struggled to turn.

I read that this was most likely a capacitor. After opening up the drill i removed the capacitor from the trigger assembly thinking I would Need to Bridge the two Points with a wire instead.

However the drill ran without this!

Question 1: Is it normal for the drill to run normally just by removing the capacitor from the Trigger asembly. I believe the capacitor is there to clean up the electricity.

While the drill runs now, it seems to take a second to get started/up to Speed but then also seems to run faster than it should.

Question 2: Is that because I removed the capacitor or am i imagining it or is the drill possibly broken in another way??

Any help appreciated!

Stoner

If this is a starting capacitor then it exists to help create a lag and difference between the two fields so that the motor will turn. One field has to "Chase " the other so the capacitor creates the difference between the two.

Small mechanical alignments can cause a tiny shift that running light can often create that shift and the motor will turn.

However it would not be a good idea imo to continue with this with a load on the drill and the increased torque and resultant current that would be produced.


I'm not sure what the capacitor is that you are talking about. However I doubt it's a filter , the drill is AC?? so it's no smoothing, so at a guess I suspect its there to create the initial shift between the two magnetic fields that once moving the drill keeps going itself.

All that said I can't explain the speed difference, the field slip should not be increased by removing the capacitor, the drill should still approach the 50hz mains drill and fall back from it.

And I could be talking about the wrong capacitor all together!!! Someone will pick me up on it.

Bruthal

Since it will likely be a universal motor in a drill, with brushes, the capacitor is not for starting.

The capacitor in the drill is just for interference suppression.

Often when the universal motors struggle to run properly, its worn brushes, or the brushes jammed in their guides, so they dont make good contact with the copper strips (commutator)

civ247

Hi,

Thanks for the replies. Ist almost certainly a universal Motor. It wouldnt run untill i removed the capacitor from the Trigger. I thought I would have to Bridge the cap left by the missing capacitor with a wire or sometihng but it ran with no modification after removing the capacitor . . I find this a bit confusing, but im not an electrician . . .

eeguy

Probably just a filter.

Have a look at this video https://www.youtube.com/watch?v=yLU_cSNogF8

The guy repairs a drill just by removing the filter, same as you.