Powersoft powerlimiting, and GFI's. Is the power limiting tripping the GFI?

J

Jack Arnott

Senior
Jan 29, 2011
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Hello All,
I have a festival where I am running the entire system off of one twenty amp circuit. And it is GFI protected.
Not ideal, but never a problem before. But this weekend I threw the GFI four times. Not the circuit breaker, just the GFI.
It is also the first time I have used the Powersoft amp at this event. I have a four channel amp, with three monitors mixes, and mid/highs,
and a two channel QSC for the lows.

One time, the performer moved the mic for the uke. I did not see what happened, but there was low midrange feedback.
By the time I looked up, the mic was back in position, but the PA was off.
Two other times it was while not much was going on, but there was a harp solo. And the harp was quite loud in one monitor.
And the other time, there was a lot going on, including a harp.

Seems to me like all scenarios for power limiting.

So, the power limiting has to be tripping the GFI. Does this seem right? Is is sluffing off power somehow, that the sensor sees less power on the neutral than the hot?
Is it sluffing it to ground?

Regards, Jack
 
Re: Powersoft powerlimiting, and GFI's. Is the power limiting tripping the GFI?

Hi Jack,

I don't know but I'd put my money on a defective GFI. First thing I'd try is swap out the GFI. I had one go up in smoke and trip the breaker all on its own with nothing plugged into it. They do sometimes just go bad. Good luck.

--Frank
 
Re: Powersoft powerlimiting, and GFI's. Is the power limiting tripping the GFI?

The more those things trip, the weaker they get and the easier they trip until just plugging anything in will trip it. Have them replace it.

(I won't tell you that I've replaced them myself as I suspect that's really not kosher...)
 
Hey Jack,

I'm no Powersoft expert but I know those guys and I've some experience with their products. I'd definitely point a finger at the GFI first. They're pretty sensitive, that's part of why you rarely see ones with high current ratings - too much gear attached to switch off because of a stray 15mA. Anything could have set that thing off. The power limiter in the Powersoft amps is all DSP, it's not "dumping" the extra juice anywhere - just not making it in the first place.
 
Re: Powersoft powerlimiting, and GFI's. Is the power limiting tripping the GFI?

Ok I'm in the UK but I use both D/Q series and K series Powersofts and like Bennett I doubt it's the amps, GFI or RCDs as we call them do get more sensitive or more prone to errors if they are dropped or regularly tripped, either test it or replace it first.
My worst experience was in a local hall here where we had all the backline and video kit off of one GFI and the cumulative earth leak of several valve amps older keyboards video kit etc tripped the thing, no one device showed any fault but we solved it by splitting the gear over 2 GFIs on the same phase and ta da no more trips. I suspect you had a similar situation cumulative build up of stray current and an over sensitive GFI.
Edit: When I re read your post are you sure your mains cable hasn't got a bad neutral or be internally damaged that could cause a voltage difference at higher currents and possibly take out the GFI G
 
Re: Powersoft powerlimiting, and GFI's. Is the power limiting tripping the GFI?

I swear I've seen a little plug in GFCI tester with two buttons - one a "should trip" current and one a "shouldn't trip" current for testing both for insensitive and overly sensitive GFCIs? I believe the limits on the cheapie home style GFCI's in the US is 6 and 4 ma. You can also "roll your own" with a power plug and resistor. In the US a resistor of 30K ohms from hot to ground will give you 4 ma at 120V. This one from the RatShack would do:
33K ohm 1/2W 5% Carbon Film Resistor pk/5 : Resistors | RadioShack.com
 
Re: Powersoft powerlimiting, and GFI's. Is the power limiting tripping the GFI?

Frank Koenig said:
Hi Jack,

I don't know but I'd put my money on a defective GFI. First thing I'd try is swap out the GFI. I had one go up in smoke and trip the breaker all on its own with nothing plugged into it. They do sometimes just go bad. Good luck.

--Frank
Click to expand...

GFCIs go bad all the time and they're often DOA. It's the GFCI.
 
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