Contactor Fault

[BangTidy]

Hi just after a bit of help with a intermentant issue I have with some car park lighting that is controlled by a time clock and 3 contactors.
The contactors are sticking in so the lighting is staying on, ive taken off the load for the lights and the CB for the time clock which resets the contactors but then a few days later the problem happens again.

Could it just be 1 of the contactors are faulty and replacing be the answer? There about 10-15 years old but wondering if could be a another issue?
Id admit contactors, not quite know the ins and out, im just wondering if anybody else might have a bit more knowledge?

Cheers

 

[Leesparkykent]

I would of thought the problem will be the timer. Is the timer mechanical or digital?

 

[telectrix]

you need to ascertain if the contactor coils are energised when they should not be. that's your starter for 10.

 

[Andy78]

Is the problem the contactors sticking or the time clock failing to de energise the contactor ?

If it's the contactor you can either replace it, or i believe some types are serviceable. If it's the timeclock, replace it.

 

[Pete999]

Same as what the others have said so far

 

[Skimpy Wan]

Had a similar issue a few weeks ago where an (analogue) Sangamo timer fed contactor for a loading area at a well knowing building merchants.

Despite the cogs being visible (at 3 o'clock on the face plate) and turning, the timer failed to de-energise the contactor, causing the lights to remain on all night. Once the timer was replaced all was ok.

 

[BangTidy]

The timer is mechanical, and there is a switch in between to overide it but when the contactors are stuck in the switch doesnt work, which think rules out the timer.
The problem is intermitant a couple of months ago it first happened and then last week has done it twice, working for a couple of days then gone again, the last time took ages to reset.

 

[Leesparkykent]

So when you went to reset it, the timer was timed off, there was no voltage present at the coil and the contactor was still closed?

 

[LankyWill]

is it a quartz timer?

 

[davesparks]

The timer is mechanical, and there is a switch in between to overide it but when the contactors are stuck in the switch doesnt work, which think rules out the timer.
The problem is intermitant a couple of months ago it first happened and then last week has done it twice, working for a couple of days then gone again, the last time took ages to reset.

Did you test the voltage at the coil whilst the contactors were 'stuck'?

For multiple contactors to develop an identical mechanical fault at exactly the same time sounds a bit far fetched

 

[BangTidy]

Sorry been working away. Yeah its quartz timer and tested it for voltage when the contactors were in and theres voltage, a switch is in between to either turn on/off/timer operation for the clock

 

[telectrix]

if the swiych is for override, then it will be in parallel with the timer contacts, so if the timer is stuck in the ON state, the switch will do nothing.