How to waste an afternoon

I have an old (2001?) JCB shredder. I've used it for several years, unjamming it now and again. Yesterday I used it and it stopped again, so I unscrewed the cover (single screw) as usual to remove the bits stuck to the blade. Only this time, there weren't any. A quick check with an ohmmeter across the mains plug showed the shredder was open-circuit. The fuse was ok.

To get at the motor I had to remove 4 screws (pozi No2), 4 x 10mm bolts with locknuts, 4 x 13 mm boils with locknuts, and the blade holder (13mm). I could then lift the motor shield up with the motor attached. To remove the motor from the shield another 4 x 5mm hex-head screws would have had to be removed, but it wasn't necessary. Having got access to the motor, I removed the leads, and an ohmmeter showed the motor winding was ok. However, the connection from the plug to the motor was open, so it looked like the switch had failed. To remove the switch box, another 4 x pozi No2 screws had to come out. But that just left me with a box with no apparent means of access. Eventually I got in by sliding back some locking wedges (see yellow pieces at each corner ). I've never seen anything like those before. Inside was a switch with an overload mechanism (below the black button in the photo), and I found the neutral connection on the double-pole switch was open. Live was ok. Although I was eventually able to get the switch apart (2 x torx No10), it wasn't repairable, and replacement switches are no longer available.

So that's it. I suppose I could short-circuit the switch and just use the mains socket to control the shredder, but that overload mechanism is there for a reason. Maybe I should just be content that the shredder has lasted many years; but it could have gone on for many more years.

One more thing. Lucky I've got a decent selection of screwdriver bits, spanners, sockets, etc! I wonder why so many different sizes and types of fixing were used.

Reply to
Jeff Layman
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It's a double pole switch, and the live part is still working. Would the overload still work if you bridged just the neutral pole on the switch?

Maybe I should just be content that the shredder has

Reply to
GB

It might, but I had to dismantle the switch to find out clean the contacts. As often happens, one of the hidden springs inside popped out as the switch came apart! I can't work out where it came from. Anyway, both sets of contacts - live and neutral - were heavily spark corroded and pitted, and would soon fail again.

Reply to
Jeff Layman

When I get into power my first rule will be that every screw will be a PZ2:-)

Reply to
ARW

My immediate thoughts were: a) Great idea! b) Won't wrist watches get rather chunky?

Reply to
GB

Bugger. And I have more wrist watches than mobile phones.

Reply to
ARW

Why not just get an alternative double pole switch and put some other sort of overload protection in the circuit, or even circuit breaker ?

Reply to
F Murtz

The switch isn't difficult - something like this should do:

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The overload cutout is more of a problem as I don't know the spec. There are some references to the switch (a Schulte Elektrotechnik 700-6/2) on the internet as a Karcher part, such as also available here but the overload mechanism is completely different. On that first link photo, it looks like the current capacity is 16A, the same as on mine. But at this page several different versions of the switch are listed with different cut-off currents (Auslösestrom Motorschutz in A - Release current Motor protection in A). Unfortunately, none is 16A!

The complete shredder switch box seems to be available here:

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at various currents, but none as high as 16A. And by the time I've paid nearly nearly 50 Euros (+ 8 Euros P&P? That's to France & Belgium - the UK isn't listed), I might as well consider replacing the whole 15-years old shredder.

Reply to
Jeff Layman

Just short it out. All it's protecting is the motor. You will likely get a few more years use out of it,just be careful not to o verload it.

Reply to
harry

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