What's this electrical component & what does it do?

[Tradewinds]

This is boaty as it involves a small grinder/polisher I'm using to fettle some bolt heads.

The G/P is a Kef-Motor 200w x 3000 rpm. They don't seem to have a presence in the UK now.

It was running as it should when suddenly 'power' dropped off. It could then stopped easily by hand - its oomph had gone and it started to run hot.

I've opened it up and all the windings look superficially fine - no burning or smell of burnt-out windings. Both bearings inside are free-running and there is no evidence of binding of the armature. In fact it looks 'as new'.

Re-assembled it & it's just the same - slower running & easily stopped by slight pressure of the hand.

The only other component (other than switch) is this:

What is it and could it be anything to do with my problem? The body is about 50mm long x 30mm dia.

If it could be the cause where could I buy a replacement part? Did a google on Bosch 0670 313 431 and drew a blank. New G/P aren't that expensive to buy, but if I can repair this one by replacing a simple component for a few bob I'd like to do so.

TIA

 

[sailorman]

This is boaty as it involves a small grinder/polisher I'm using to fettle some bolt heads.

The G/P is a Kef-Motor 200w x 3000 rpm. They don't seem to have a presence in the UK now.

It was running as it should when suddenly 'power' dropped off. It could then stopped easily by hand - its oomph had gone and it started to run hot.

I've opened it up and all the windings look superficially fine - no burning or smell of burnt-out windings. Both bearings inside are free-running and there is no evidence of binding of the armature. In fact it looks 'as new'.

Re-assembled it & it's just the same - slower running & easily stopped by slight pressure of the hand.

The only other component (other than switch) is this:

What is it and could it be anything to do with my problem? The body is about 50mm long x 30mm dia.

If it could be the cause where could I buy a replacement part? Did a google on Bosch 0670 313 431 and drew a blank. New G/P aren't that expensive to buy, but if I can repair this one by replacing a simple component for a few bob I'd like to do so.

TIA

is it a capacitor i have had one burn out in my Belle mixer. replaced off the shelf at a local auto electrical shop, not expensive

 

[AntarcticPilot]

It's an electrolytic capacitator with a capactance of 3 micro Farads and a voltage rating of 400 Volts. It probably stops large surges on starting or stopping., but that's just a guess. They do go bad, so it could be the problem, but I wouldn't stop looking for other things.

This is boaty as it involves a small grinder/polisher I'm using to fettle some bolt heads.

The G/P is a Kef-Motor 200w x 3000 rpm. They don't seem to have a presence in the UK now.

It was running as it should when suddenly 'power' dropped off. It could then stopped easily by hand - its oomph had gone and it started to run hot.

I've opened it up and all the windings look superficially fine - no burning or smell of burnt-out windings. Both bearings inside are free-running and there is no evidence of binding of the armature. In fact it looks 'as new'.

Re-assembled it & it's just the same - slower running & easily stopped by slight pressure of the hand.

The only other component (other than switch) is this:

What is it and could it be anything to do with my problem? The body is about 50mm long x 30mm dia.

If it could be the cause where could I buy a replacement part? Did a google on Bosch 0670 313 431 and drew a blank. New G/P aren't that expensive to buy, but if I can repair this one by replacing a simple component for a few bob I'd like to do so.

TIA

 

[theoldsalt]

This may help

http://www.ebay.co.uk/itm/3-uf-mfd-...-capacitor-flying-lead-mounting-/320905266096

 

[pvb]

It's an electrolytic capacitator with a capactance of 3 micro Farads and a voltage rating of 400 Volts. It probably stops large surges on starting or stopping., but that's just a guess. They do go bad, so it could be the problem, but I wouldn't stop looking for other things.

The capacitor isn't there to protect against surges, it's a key component in the motor circuitry. In simple terms, it provides a phase-shifted AC supply to a second winding on the motor. If it fails, the motor won't run at all, or won't run properly.

 

[Westerly Jetstream]

Cost a few pence from either RS or Farnell I'd plump for it first thing .The manufacturer is irrelevant any 3 microfarad 400v will do job. 90% of motor problems are the cap.

 

[AntarcticPilot]

The capacitor isn't there to protect against surges, it's a key component in the motor circuitry. In simple terms, it provides a phase-shifted AC supply to a second winding on the motor. If it fails, the motor won't run at all, or won't run properly.

Thanks; I live and learn!

 

[savageseadog]

It's an electrolytic capacitator with a capactance of 3 micro Farads and a voltage rating of 400 Volts. It probably stops large surges on starting or stopping., but that's just a guess. They do go bad, so it could be the problem, but I wouldn't stop looking for other things.

Not just 400V but 400VAC continuous, very important! It's known as a motor start capacitor.

 

[nigelmercier]

The capacitor isn't there to protect against surges, it's a key component in the motor circuitry. In simple terms, it provides a phase-shifted AC supply to a second winding on the motor. If it fails, the motor won't run at all, or won't run properly.

+1

 

[Tradewinds]

Thanks everybody.

Will this do from Maplin?

http://www.maplin.co.uk/motor-run-capacitors-440v-30309#specification

Part No: RG63T 3 30 x 53 6.3mm double spade deck

 

[Westerly Jetstream]

Yep that will do just dandy.

 

[earlybird]

Since it's a start capacitor, and your motor does start, a replacement is unlikely to cure the problem IMHO.
My money would be on burnt out windings, despite their not showing the signs.

 

[Norman_E]

I think that is a capacitor start and run type of motor, therefore replacing the capacitor with one rated as a motor run type is the first thing to try. I did note however that the motor is pretty low powered for use as a polisher, and may well be overloaded in use.

 

[Tradewinds]

I think that is a capacitor start and run type of motor, therefore replacing the capacitor with one rated as a motor run type is the first thing to try. I did note however that the motor is pretty low powered for use as a polisher, and may well be overloaded in use.

Probably is underpowered - it's used by my MIL for jewellery work - I just wanted to do a few bolts - buggering it up in the process!!