draining filter caps

11tsteve

how do most around here do this procedure?

Habanero Monk

Whats the voltage? Usually with resistor to ground.

lanchile

well, you can do it with resistor (Bleeder) or just shorting out the + and - with jumpers. Note that some of big caps and bank of caps can hold a lot of juice and can injury you badly or can kill you.

What I always do is get two jumpers and connect one to the + and the other one to the - and I touch the jumpers together...that way if the cap is fully charged, the jumpers will ark. I used to do it just touching both terminal with a screwdriver but e few times the caps's terminals were damage for the big spark. resistor are good to do this too (no sparks), but it will take a little long to discharge caps.

Glen B

+1 bleeder resistor.

11tsteve

so for the large filter caps in my B&K, the bleeder would be something like 1000 Ohm? and hooked to the cap with jumpers?

CoolJazz

You should not us the mentioned shorting method like a screwdriver or similar! You can most importantly injure yourself this way or damage the equipment. A discharge this way can damage the capacitors but more importantly have violent and unexpected things happen. It's not uncommon to arc wield off the end of your screwdriver! Respect your tools more than this! I've seen clip leads instantly burn off the jacket and start to glow.

1K may not be light enough. The higher the load, the more it'll have the possiblity of heating up the resistor and even causing it to open. Or burn yourself. I'd suggest trying to find something above 5K, more like 10K with a higher wattage rating being the preference. The lower the value, the higher the wattage needed.

If this is more than a one time thing, make a safe bleeder. Take a clip lead, cut it in the middle. Slide heat shrink over each half and solder in the resistor. Then bring heatshrink down over the leads completely to try to illiminate the possibility of any shock hazard to yourself or shorting to any equipment. If you have heatshrink that will go over the resistor, that's kind of nice. If you're flowing to much current, you can see it in the heatshrink versus not being able to see it in a resistor.

Then remember that you can check with a voltmeter to see before and after exactly what voltage is present on the caps. Unless you use a resistor into the hundreds of K's, you're talking a discharge time of 15 sec to maybe a couple minutes. Taint no big thing as your clipping on each end carefully, watching your resistor for too much heating and monitoring the voltage drop. It's quick, easy, clear whats happening and above all, safe for you and the equipment.

CJ

11tsteve

thank you very much. there is so much conflicting info on the web about this procedure.... I just wanted some input from real people dealing with their gear.