Voltage spike

[CH123]

Hi Can anyone tell me whether a normal rail mounted lighting contactor can cause voltage spikes?We have replaced 4 emergency gear trays on a site in the last week, 2 of them have only lasted 24hrs!!!The new fittings have electronic ballasts.....just trying to find out what's going on!!!!!Have also tried different manufacturer case we got a bad batch.Any ideas would be much appreciated.

 

[WDMDL]

Shouldn't be a problem... Any voltage spike on the coil circuit will appear mainly across the switch contacts as they are opened. Hardly anything will appear on the supply or load side of the contactor

The contactor opening and closing the circuit to the lights shouldn't cause them a problem either. Electronic ballasts shouldn't cause an inductive spike as they are de-energised.
However a poor connection or bad contact on the contactor could cause a problem because the circuit usually has a low value resistor or NTC thermistor to limit inrush current. Multiple inrushes can cause the resistor to burn out.

Also mixing electronic and magnetic ballasts on the same circuit may cause problems, but likely only if the conventional fittings don't have PFC caps.

Simon.

 

[CH123]

Thanks for the info, abit of food for thought. I don't think the existing units are magnetic ballasts, so gonna give the contactor a good once over tomorrow.Thanks again

 

[platty1005]

Sounds like mains problems not the contactor