I am testing this ballast : http://www.lighting-gallery.net/gallery/displayimage.php?pos=-57170 its 250W HPS

First i am trying to figure out if there are shorted windings in the coil. I connected the ballast alone to 240V (to the 2 ends of the coil) to see if it heats up normally or too fast

Most ballasts when i test them like this make "hummmmmmm" sound

This one makes sometimes "hummmm" sometimes "zzzzzz" and there is also some sound of rattling inside (either a loose piece of something rusted or small arcing)

But it does not heat too fast either

Is it intact or not ?

Ash: When you test a ballast, you must to connect a lamp to it. Don't connect it alone as it may overheat and fail.

Update :

I shaked it a bit and some pieces of rust fell out. Now it was much more silent in the test

When i connected it with passive ignitor (that generates 5KV across the coil) it made "SNAP SNAP" sounds much louder than the more normal "click click". But there was no hint of arcing, so i guess its just the normal sounds of this ballast

I connected it with a lamp and it works ok



@dor123

If the ballast is ok, it will heat up slowly. It takes more than few minutes like that to overheat a good ballast

If the ballast is shorted inside, it will heat up fast and/or trip the breaker. If i connected it right away with a lamp and ignitor and it was shorted, i could damage them and possibly explode the lamp. By testing the ballast alone first i eliminate this risk

I have another 250W ballast that was shorted (from isolation breakdown in the wires going to the lamp socket), it overheated and caught fire. But it took hours to overheat like that, and i think it didn't happen in one day either : http://www.lighting-gallery.net/gallery/displayimage.php?pos=-57275