Jet BD31a Power Transformer Leads Chopped

[HantsHog]

Pictures of the cables, NVR switch and junction box are attached. I've also produced a schematic diagram. Whilst taking the 'photos I noticed a third cable has been cut from the NVR switch.

I have purchased, from a school, a second hand Jet BD31a Disc & Belt Sander that is integrated with its own closed floor standing cabinet. Inside the cabinet is an enclosed junction box that has four power leads coming out of it. Two leads go to the NVR switch which and are fine and two are severed.

The NVR switch as four leads, one goes to the motor, two to the junction box and one that is severed.

One of the severed leads would have been for the mains (single phase) three pin plug. One of the other leads, or both, supplied a chip extractor (so that when the sander powered up so did the extractor). I'm not bothered about the extractor power lead and will isolate it.

How do I tell which lead should have the mains plug connected as there doesn't seem to be any obvious indication?

Thanks

 

[HantsHog]

Added pictures of problem with further details of third severed cable.


Thanks[/quote]

 

[Racers]

Can you open the box and take a picture on the insides?

Pete

 

[Eric The Viking]

At a guess, the easiest thing would simply be to completely rewire it, but that's not hard:

Incoming mains lead into NVR switch (they usually have the load side marked). If not marked try it one way round: if it doesn't click when you apply power and push the switch, it's the wrong side!

Other (load) side of NVR to motor.

Earth of incoming mains to everything metal, and probably earth lead going to the motor, if that cable is long enough to reuse.

I suggest you get a decent crimp tool and some Lucar (spade) crimp connectors of the right size. The connectors are cheap and it's well worth it for a tidy result. Remove the 'mystery box', which most probably houses either a connector block or a relay+connector block, to send power to the DX (if the same DX is used by several machines, that would have needed 'clever' wiring.

No guarantees, but, unless there's something really odd involved, starting again from scratch is quickest, and you then know for certain what the wiring is!

E.

PS: again a guess: either B or D go to the DX, the other one is from another machine. One incoming feed from the NVR is switched live, the other is permanently live as far as the relay in the box. But there has to be some arrangement to stop the second extracted machine from starting the sander remotely!

Only Connect...

 

[HantsHog]

Eric,

As I do not need to connect this machine back to an extractor I agree it'd be easier to strip the NVR and wire in the mains supply and motor. I thought that if I could just attach a three pin plug somewhere it would be easier but no.

That mystery box contains what appears to be a couple of relays or even another NVR. Whatever it does it's coming out. I'd put it on eBay if I knew what it was!

Thanks for the help.

 

[Eric The Viking]

Aha! (smug feeling).

'Tis probably as I thought: the box is switching the extractor for at least one more machine and probably just happens to be in this machine's case because it was convenient for some reason. There shouldn't be any issues in just removing it and putting the wiring back to a simple NVR.

Have fun!