contactor burning out

[mcm]

I recently fitted a new contactor three phase 10amp with 230volt coil, now it was working fine for about two weeks and now seems to have burnt out. I can not manually push the contactor in even using a screwdriver as it is solid. The overload is set to 4 amps so shouldn't be a problem with that has anyone have any ideas why it has burnt out? I have heard it could be caused by a drop in voltage on a phase but what would cause this as it all tested out at 230volt before it went wrong.

 

[Pete999]

What is the contactor controlling?

 

[Marvo]

If it's not mechanically interlocked with another device then I'd just remove it and dismantle it to see what caused the problem.

 

[Deleted member 72666]

When you say 'burnt out' do you mean the contacts or the coil? If the contacts have welded shut then too much current is being drawn. If so what is the load and duty cycle? If the coil has burnt out then it's either massively under or over voltage being applied, again what is the duty cycle? Has the coil been noisey in it's operation?

 

[Deleted member 72666]

Another thought, what is switching the contactor and do you have a circuit diagram? Also what make of contactor is it?

 

[Pete999]

I asked the OP what the contactor was/is controlling not had a reply yet, the answer may give us some clues

 

[mcm]

The contactor is for a joinery machine. It has a push start button to start on the front of the panel box along with the push stop button. When I say burnt out I mean the coil seems to burnt and the contacts welded not allowing the contactor to close even manually. The contactor is a brook crompton one. The overload is set to 4 amps and the contactor is 10amps so if it was to much current being drawn it would have to be over the 10amps to cause the contactor any damage .

 

[Pete999]

Sounds as though this is a DOL starter is that right? maybe start up current has caused the contacts to weld together over a period of time. "The coil seems to burnt" sorry is that a typo?

 

[Deleted member 72666]

Is this 'control panel' approx.12" x 10" and made from aluminium with a reset button at the side? In other words is it a Brooks starter?

 

[Marvo]

Is this 'control panel' approx.12" x 10" and made from aluminium with a reset button at the side? In other words is it a Brooks starter?

Is that just a wild guess or have you been peering through the OP's garage window?

 

[mcm]

The panel has the push start on the front and the stop button also. The machine is formed of three parts that are switched by three start buttons that are in depended from each other. At first it was the overload that was not working so that was replaced and worked for around two weeks then the contactor coil went. The contactor was changed now the contactor has welded shut and coil burnt out. Any ideas what would cause this? All the connection are correct and it was working for two weeks before it went.

 

[Deleted member 72666]

Is this 'control panel' approx.12" x 10" and made from aluminium with a reset button at the side? In other words is it a Brooks starter?

Forget this post as I've re read your post again and decided it can't have been one of these as they'd stop making them decades ago! But what I will say is was the contactor suitably rated for its application, is it rated AC1 ?

 

[netblindpaul]

AC1?
Surely you mean AC3?

 

[GMES]

think it is time to get the megger and avo out and test whatever that contactor is supplying, before you go any further.

 

[Deleted member 72666]

AC1?
Surely you mean AC3?

If he'd chosen AC1 then it would explain a lot?
Sorry, I should of added 'by any chance' on the end of my last post!