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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> single phase contactor https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1315859941 Message started by dace on Sep 12^th, 2011, 9:39pm

Title: single phase contactor
Post by dace on Sep 12^th, 2011, 9:39pm

contactor feeding immersion with thermostat cant stop chatting off and on, any ideas please

Title: Re: single phase contactor
Post by CWatters on Sep 12^th, 2011, 10:59pm

I have no practical experience with contactors but read that chatter can be caused by low voltage. So perhaps the supply cable is too small a CSA or too long? or loose connection? eg When immersion heater turns on the voltage drops causing the contactor to drop out, immersion heater switches off, voltage rises, contactor turns on again. Repeat rapidly.

or perhaps the immersion has a high inrush current which causes the same effect (eg dipping the supply voltage). Perhaps a contactor with a longer drop out time would work? Perhaps a time delay relay in there to get past the in rush?

Title: Re: single phase contactor
Post by Lectrician on Sep 13^th, 2011, 6:53am

More than likely an old dodgy contactor.

Title: Re: single phase contactor
Post by sparxxxx on Sep 14^th, 2011, 6:41pm

Incorrect or faulty hold on circuit - contactor closes, hold on contact opens, contactor opens, hold on contact closes, contactor closes until the coil burns out.

Title: Re: single phase contactor
Post by Lectrician on Sep 14^th, 2011, 9:02pm

It wouldn't be latching if just controlling an immersion heater, unless it is wired incorrectly.

I took it that this once worked and now doesn't.

Title: Re: single phase contactor
Post by The_Trician on Sep 14^th, 2011, 10:03pm

If it's the thermostat wired into the control cct it could be the stat which is intermittently making & breaking.....