Oscillating Spindle/bobbin sander startup issue

[Sachakins]

Hi, I have a generic bobbin sander, it's not had a lot of use, but today, when pressing start button, motor hummed but not working.
In desperation I tried spinning the bobbin by hand, then it ran ok.
This happened about 5 times today, so have abandoned sanding on it today.

Before I tear it apart, does anyone have suggestions on what the problem may be, or even what should I be looking for when I open it up to investigate.

Really need to get it running, load of internal curves to sand.

Cheers

 

[gwaithcoed]

Typical of a faulty capacitor.

 

[Old.bodger]

Yep almost certainly the capacitor. Just swap like for like. Attention to the correct voltage rating.

 

[Spectric]

Attention to the correct voltage rating

and capacitance

 

[Sachakins]

Thanks, I'll strip it the weekend. Any idea what sort of cost I would be looking at?

 

[Cabinetman]

Thanks, I'll strip it the weekend. Any idea what sort of cost I would be looking at?

One and only time I bought one it was three or £4, just be careful it may be charged when it arrives so put a screwdriver across the terminals to defuse it, same with the one you are removing, you can get a nasty jolt from them. Ian

 

[Sachakins]

Hi all,
Long delay to get to it for repair, life in way of hobby, Got a matching capacitor today, old one out new one in, rebuild and test.

It's alive and working well again, thanks to each of you for help. Just cost £5 and back in business

 

[Old.bodger]

Good result !

 

[Sachakins]

Good result !

Thanks, I managed to find one with not only matching voltage and capacitance, but with all the same lettering and codes.
Wasn't sure if just CBB60 8uF 450v was all I needed, so made sure it had 25/70/21 50/60hz on it too, as some other CBB60 8uF 450v had 40/70/21 or something similar.
So not being a spark, went for exact match, not sure if that matters, but safe than sorry approach.
Very happy turner tonight.

 

[DBT85]

Nice to see a tool saved rather than junked for a low cost part.

 

[Sachakins]

Nice to see a tool saved rather than junked for a low cost part.

Me too, I always have a fiddle first, sometimes though it's sadly uneconomical to fix. But in this case totally a win win, it goes and I've learned something new, such a good feeling.

 

[MikeK]

Thanks, I managed to find one with not only matching voltage and capacitance, but with all the same lettering and codes.
Wasn't sure if just CBB60 8uF 450v was all I needed, so made sure it had 25/70/21 50/60hz on it too, as some other CBB60 8uF 450v had 40/70/21 or something similar.
So not being a spark, went for exact match, not sure if that matters, but safe than sorry approach.
Very happy turner tonight.

Good job! The 8uF 450V was the important specification. The 25/70/21, 40/70/21, or similar number groups, is the climate class for the capacitor. The first group is the lower operating temperature in Celsius (read as a negative number), the middle group is the upper operating temperature in Celsius, and the third group is the number of days the capacitor can operate at 95-percent humidity and +40 degrees Celsius.

In your case, the capacitor is rated for normal operation from -25 to +70 degrees Celsius, or 21 days at 95-percent humidity and +40 degrees Celsius.

 

[DBT85]

Me too, I always have a fiddle first, sometimes though it's sadly uneconomical to fix. But in this case totally a win win, it goes and I've learned something new, such a good feeling.

Same here. Can't save them all sometimes but it's quite satisfying when you get one.

 

[Sachakins]

Same here. Can't save them all sometimes but it's quite satisfying when you get one.

But like fishing