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!

[andy198712Participant @andy198712]

Well it’s working lovely, the angular contact bearings are giving a nice surface finish and the lathe is working beautifully! Very happy.

 

Couple bits I made up

 

[Les Jones 1Participant @lesjones1]

With the board removed from the lathe and on an insulated surface connect the L (Live) and N (Neutral.) to the mains with a 100 watt old fashioned filament bulb in series with the live lead.
Tell us if the bulb does not light at all, lights dimly, or light to full brightness. Measure the voltage between the L & N teminals on the board.

Les.

[andy198712Participant @andy198712]

Just blown again sadly 🙁

a mosfet has a hole in it, went with quite a pop!
blew the fuse first, replaced it and it blew that. Replaced mosfet off my old board and now it trips the garage rcd again when turned on. Could be the replacement mosfet off my old board is faulty and I picked the one faulty one from the 5.

 

but I think I’m going to go the industrial sewing machine motor route now. 750 w jack motor one

[Robert Atkinson 2Participant @robertatkinson2]

Just remember that those motors do not meet UK electrical or machinery safety standards and the nominal voltage is incorrect (220V not 240). They almost certainly don’t meet EMC requirements either.
I can tell they don’t meet safety standards just from looking at the photos in ebay listings. The use of Mate-N-Loc connectors with loose rubber boots for example. These should only be used on circuits above about 50V when behind covers that require a tool or key to remove.
The certification paperwork confirms this

https://docs.rs-online.com/6aa4/0900766b80113ee5.pdf
https://uk.rs-online.com/web/p/wire-housings-plugs/0848953

You may do what you want in your own workshop but should be aware of the risk an status of such work.

 

[andy198712Participant @andy198712]

Id be planning to buy from a U.K. shop not eBay or Ali for the quality and warranty was my plan 🙂

 

example here

https://www.tysew.co.uk/jack-jk-563a-750w-1hp-heavy-duty-energy-saving-servo-motor?search=Motor

[Robert Atkinson 2Participant @robertatkinson2]

Unfortunatly I don’t think you will get much protection from them.
There is not much detail in the photo on the Tysew website so I did a search on the model. Another company came up Industrial sewing https://www.industrialsewing.co.uk. The website is identical as is the address and phone number. Being a cynic I searched sew Iver and found a number of websites and companies with the same address:

https://www.berninasewingshop.co.uk/
https://www.tysonsewingmachines.co.uk/
https://www.brothersewingshop.co.uk/

The address does not look too good either https://www.google.com/maps/place/32+The+Ridgeway,+Iver+SL0+9HW/@51.5140584,-0.5064902,3a,59.1y,337.84h,94.21t/data=!3m7!1e1!3m5!1sc9V3WyX2ism4P_2onCH4vA!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D-4.211761436668866%26panoid%3Dc9V3WyX2ism4P_2onCH4vA%26yaw%3D337.84431677786574!7i16384!8i8192!4m6!3m5!1s0x48766e27fbf3074d:0x9c6d1544853c92bd!8m2!3d51.5143284!4d-0.5066301!16s%2Fg%2F11ckqs0lf7?entry=ttu&g_ep=EgoyMDI1MTAyMi4wIKXMDSoASAFQAw%3D%3D

The JK-563A still uses the Mate-N-Loc connectors and I doubt many sewing machine shops understand the requirements of the Low Voltage and EMC directives. I can’t find a manual for it anywhere online either.

Robert.

[andy198712Participant @andy198712]

Hmmm interesting!
i appreciate that. It sort of screams scam doesn’t it?!

so where to go from here? Find a bricks and mortar shop or ?! Some sort of speed controller that’s reliable for the stock motor or full motor and controller swap… cost and expertise is going up here though…

[Robert Atkinson 2Participant @robertatkinson2]

I don’t think you  are going to get a different motor unless you buy one from a Jack authorised seller in europe. Closest seems to be Belgium.
I don’t know if the ones on ebay  etc are clones but anyone other than a authorised dealer is likely to be selling the same kit.

Robert.

[andy198712Participant @andy198712]

What’s the down side of the mate n loc fittings too? They seem like molex? The ones on the stock board can just pull/possible to vibrate out as a comparison?
mine havnt but I mean there’s no lock ect

[Robert Atkinson 2Participant @robertatkinson2]

They are fine for their intended use. This is either safe low voltage (<50V) or, as used in the SX2, higher voltages inside the machine where you need a tool to get to them i.e. “not user accessible”. There are a number of issues. There is not enough distance between the end of the plastic and the potentially live metallic parts. They could be touched when trying to unplug or by something metallic the user is holding or wearing.
The contacts are not positively retained and can pull out if you pull on the wires. There is no strain relief for the cables either. The soft rubber boot does not fix this.
The cheap copies also have a habit of over-heating. Even the genuine ones can overheat and fail if all the contacts are carrying full or near full load.

Robert.

[andy198712Participant @andy198712]

Robert,

 

right okay I’m with you now. This could be changed to something more suitable and adding strain relief wouldn’t be much of an issue.

trouble comes of you start modifying it you’ve voided any warrenty anyway.

i guess I wanted the U.K. based company and the warrenty thing as more of a reassurance of some sort of quality more than anything.

 

don’t suppose you can put me down the right route of a more suitable connector?

I do appreciate the input

[andy198712Participant @andy198712]

This company seems safer

 

https://www.college-sewing.co.uk/jk563a-220v-750w1hp-jack-servo-motor.html

[andy198712Participant @andy198712]

Or I roll the dice and buy an eBay lathe motor and controller from China like this

 

https://ebay.us/m/tvIwYl

 

feedback isn’t bad, 1100w and could fit into the lathe packaging better…

[Robert Atkinson 2Participant @robertatkinson2]

You can keep the connectors but to be compliant they should be under a cover with strain relief for the cables.
Be careful with the speed control. I’ve heard reports that it is not isolated fro the mains so needs to be in an earthed metal enclosure.
You need to make your own assesment of risks. Assuming it’s only you using the machine.

Robert.

[andy198712Participant @andy198712]

Cheers Robert,

 

found a sewing machine shop 15 mins from me that have motors, going to have a chat in person.
they sell and maintain machines for the MOD apparently so must be up to scratch or Atleast I can quiz them on it (I work in the mod so won’t be fooled that “mod contracts” are worth anything lol)

[Author]

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