Bang! Flash! Nasty Surprise :-(

[tekno.mage]

Botheration - my partner was using our old Jet lathe yesterday evening (making a tool handle) and there was a bang & flash from the motor area and the lathe stopped. On investigation it seems at the very least the start capacitor had gone to meet it's maker :-( The vent was blown and the capacitor itself was somewhat warm and stinky.

Found a suitable capacitor for sale online at the right value (100uF) and right physical size - and was surpised to find this was not from an electronic components supplier like Farnell (out of stock), Rapid (nothing suitable) or Maplin (too expensive and wrong phyisical size) but from Amazon! £4.75 with free delivery. Now we just have to wait for it to turn up to discover if the motor itself is still okay.... Fingers crossed.

 

[henton49er]

Gulp! :shock: :shock:
At least you did not set your workshop on fire!!

I hope you will be able to tell all the details tomorrow.

 

[tekno.mage]

Gulp! :shock: :shock:
At least you did not set your workshop on fire!!

I hope you will be able to tell all the details tomorrow.

Definitely. It wasn't a very big bang & flash - just enough to make you jump, then swear when you realised the lathe was no longer working. It was only a small 100uF 125v capacitor, not those great big baked bean sized things you get with big motors or inside large power supplies - those are really scary when they blow

 

[CHJ]

..It was only a small 100uF 125v capacitor,....

Are you sure that was the original?

Seems a rather low working voltage, would have expected 250 volt minimum, and personally try and fit 440 volt replacement versions if physically possible. And if there is any doubt about rating/function I fit a run rated version.

As to suppliers, I have had good service from these folks in the past

 

[tekno.mage]

I thought that 125v voltage was rather low myself, Chas - but it really *was* the original capacitor - Taiwanese of course and from the mid 1980s. I've gone for a 250V replacement as the 400V ones were physically too large to fit without modification of the motor cover.

Thanks for the link to the other supplier - may be useful in the future.

 

[OldWood]

The 125v indicates that this is a modern 'chinese' motor (actually the 'chinese' part may not be totally accurate but I've met a couple like this recently from that source!) with a tapped stator winding rather than a secondary start winding.

The characteristic I've noted is that these motors start at a slower rate.

The advantage is cost, in that voltage rather than capacitance is the driver for capacitor cost by a significant factor. There will also no doubt be a cost benefit in having just one winding - I'm not sure if there is a centrifugal switch even.

Rob