SC2 mini lathe pops RCD when turned on?

[noel shelley]

On noel shelley Said:

If you don’t have one I can highly recommend a desoldering iron/ tool of the suction type ! It will make the job easy and almost fun and at about £80 may save other damage. I went for the type where the suction pump was in the box NOT in the handle as it made it smaller and easier to use.

Testing the motor with a multi meter for a leak may not show much. You need an insulation tester/ megger type  running at 500v or so to get a real reading. Noel.

Oh I’ve never heard of those, sounds better then the copper wick type rope you see!

[Ketan Swali]

On Ketan Swali Said:

Hello Andy,

I would suggest that you call and speak with Ian at ARC for suggestions.

Ketan at ARC

Good shout I’ll ring your guys tomorrow, thank you !

[Robert Atkinson 2Participant @robertatkinson2]

Hi Andy,

The different readings on the mains input are due to capacitor charging. If your DMM has a diode test you should check the diodes in the bridge rectifier.
With red lead on + terminal there should be over-range to the other 3 pins. Same with black on – terminal. With black lead on + terminal you shoud read about 0.6-0.8 (forward voltage) with red on either ~ terminal  and over-range with red to – terminal.
With red lead on – terminal you shoud read about 0.6-0.8 (forward voltage) with black on either ~ terminal  and over-range with black to + terminal.
All tests with board disconnected. When measuring between + and – you will get a very slowly changing reading so give it time to settle.

The alternative part for the IR2110 is just lead-free http://www.digikey.co.uk/en/products/detail/infineon-technologies/IR2110PBF/ so direct replacement.

Unless ARC come up with something and assuming the bridge rectifier checks out OK I’d change all 6 IGBTs and 3 drivers.
Experience, somtimes with much more expensive parts, with repairing this type of high voltage equipment has shown it is a false economy to change just one part. This is even if one part is obviously faulty. The other parts may have stressed by the failure and fail next time it is turned on. Even if not damaged the new part may have slightly different charateristics and this can cause issues.

Robert.

[andy198712Participant @andy198712]

Well, an update is due!

I spoke to Arc who went way above any expectations you would have of a company, extremely helpful and in the end I just sent all the electronics to them to be tested on their rig which confirmed a major but invisible fault with the control board causing quite a severe blow.

 

after thinking it over I just decided to buy a new board from Arc, for piece of mind, ease and speed and  also the board was 12 years old so just felt right. I do have my old board should I get time to strip that slow time (realistically it’ll sit in a box for months…)

 

im just reassembling the lathe now having swapped out the original bearings for the Arc angular contact bearings (why not while I’ve got it stripped) this was pretty easy.

Now just wiring it back up slow time going over my pictures of the strip.

One thing I foolishly didn’t picture was the kill switch wiring, there’s 4 equal size terminals I’m trying to work out and don’t want to chance getting them wrong so if I can’t find any good google pictures over the weekend I’ll no doubt ask my savours at Arc again, patient people that they are!

I’ll let you know how I get on!

[Author]

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