PLL Fixture blowing fuses but only after several seconds?

[Devilman]

Hey all, I have a few 2x 55w PPL fixtures around and recently one has acted up.

At first I thought just random fuse blow or whatever, put a new fuse in and it came back to life just fine, went back to check it later however and found the light to be out again. Replaced the fuse again and the light powered up fine but about 10 seconds later it went out again, no buzzing or odd noises from the lamps or ballast.

For reference, its connected to a standard 3pin outlet, 240v mains supply (UK) and using a 3amp fuse, which should be plenty. (I didn't really fancy putting bigger fuses in when they should not be needed)

Any ideas on the possible cause? Faulty ballast? Its obviously not an instant dead-short, as the fixture illuminates for some seconds before dying again.


Cheers all

 

[maryjane481]

I would replace the ballast. It takes 10 sec. to overload the circuit.
It seems like a soft short in the transformer. Insulation breakdown.

 

[Devilman]

Yeh now about to stick a new ballast in it from one of my other fixtures.

Hopefully it will be fine then.

Any specific things that might have caused breakdown? too much heat / humidity? or purely an age thing?

Thanks