Imet Saw Problem

[Brad93]

my imet saw has ceased to run.

It now only runs if I hold the switch across on this relay.

Any ideas?

Microswitches are all depressed as they should be.

 

[knighty]

check the voltage across A1 and A2, those are the coil windings

if there's power there and it's not working the coil is duff, easy to replace the contactor, look on ebay - but check the coil voltage... look at the other sides of yours, it should have the coil voltage there somewhere - probably 240v but worth checking (sometimes use lower voltage so safty switches etc. can run at a lower/safer voltage)

 

[Ton-up]

Says 24v coil on front, (it will be a.c.), so as knighty says you should have 24v across A1 - A2.
If its 24v then you will have a transformer, so check you have voltage there.

 

[knighty]

Says 24v coil on front,

doh! should have seen that!

EDIT: now I think about it... I think I've got some 24v coil contactors that are no good to me... I'll have a look, yours for free if you need one

 

[pressbrake1]

Bandsaw or chopsaw?
If bandsaw my imet has blade tension switch and a couple of safety guard switches

 

[Brad93]

I’ll have to get hold of a multimeter to test it.

Its a bandsaw.

I doubt it’s any of the safety switches as what happened was, pressed the switch, saw jerked into life, then stopped straight away.

A burnt out contractor or transformer seems more likely.

And it runs if I hold the manual switch on the contractor.

 

[Brad93]

I’ve found a replacement contractor if it turns out to be that.

https://uk.rs-online.com/mobile/p/contactors/0758709/

 

[Paul.]

This A1 connection looks a bit suspect, I would remake that even if it turns out not to be the problem.

 

[pressbrake1]

I’ll have to get hold of a multimeter to test it.

Its a bandsaw.

I doubt it’s any of the safety switches as what happened was, pressed the switch, saw jerked into life, then stopped straight away.

A burnt out contractor or transformer seems more likely.

And it runs if I hold the manual switch on the contractor.

Sounds like the micro switch on the bellville washer blade tensioner. Tighten it and you will hear the microswitch click and then the saw will work.
Mine does the same thing

 

[Brad93]

This A1 connection looks a bit suspect, I would remake that even if it turns out not to be the problem.

View attachment 193944

Yes I also thought it suspect but it is in there okay.

I’m going to make a new enclosure when I fix this so will get it all sorted.

 

[Brad93]

Sounds like the micro switch on the bellville washer blade tensioner. Tighten it and you will hear the microswitch click and then the saw will work.
Mine does the same thing

Will look into it.

Won’t be home till the weekend now.

 

[Brad93]

I’ve put a multimeter across A1 & A2, I’ve got nothing.

 

[Brad93]

Am I doing this right?

 

[pressbrake1]

There is a safety switch on the blade guard.
Blade guard switch and blade tightness micro switch must be made.
Ive hot the same saw, please believe what im saying!

 

[WorkshopChris]

Is this with the saw turned on just as you would expect it to run? if yes then you need to find the transformer and look for 24v there.

 

[Brad93]

There is a safety switch on the blade guard.
Blade guard switch and blade tightness micro switch must be made.
Ive hot the same saw, please believe what im saying!

How do I test the switches? They are both depressed

 

[knighty]

test again with the start button pressed in

then trace the wires going into A1 and A2 back (one will just go to negative), and keep testing the switches/whatever until you find something with power going on and nothing coming out... that's where the problem is

(so keep one probe in the negative (A1 or A2 whichever it is) then use the other probe to probe the along the other wire)

as above, probably a safety/limit switch

 

[pressbrake1]

How do I test the switches? They are both depressed

First back off blade tension then re tighten until you hear the limit click

 

[Brad93]

Solved it. Bad fuse

 

[Brad93]

I’ll expand on the above.

I tested both microswitches using the continuity function on my cheap £9.99 multimeter.

Both were working, showing continuity when switches were depressed.

I checked continuity of the wiring at the control box. No problems there.

I took the transformer out, turned the saw on and had 24v. So that wasn’t the problem.

I’d already checked a small fuse block on top of the transformer, two fuses for the incoming, and one fuse for the outgoing 24v.
I was getting a weird result testing the continuity on the fuse.

Replaced the fuse, hey presto, saw worked.

That is the fuse that supplies power to the switch, and the two microswitches.

Hence why I had no voltage on the microswitches or the switch, and though the transformer was out.

Maybe this will help someone in the future.