Power distribution question (Serious) [Archive] - Audio & Video Forums

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Florian
02-23-2009, 06:59 AM
Hi guys,

the simple problem is that my amplifiers draw too much current for one phase. Below is my power line how it is today and the requirement for each amp.

Phase1 = 40amp = 230volts
Phase2 = 40amp = 230volts
Phase3 = 40amp = 230volts

Phase1 = 8x 16amp lines (cant obviously max out over 40amps)
Phase2 = 10x 16amp lines (cant obviously max out over 40amps)
Phase3 = 10x 16amp lines (cant obviously max out over 40amps)

For best sound and no ground loops it would be best to run all the electronics on one phase alone with the same ground.

Krell KRS200#1 = 11Ampere
Krell KRS200#2 = 11Ampere
Krell KAS#1 + #2 = 10Ampere
Krell KAS#3 +#4 = 10Ampere
Krell MDA500#1 + #2 = 20Ampere (too come soon i guess)

So in total i need at least 62ampere on 230volt (124ampere on 115volt) that is without taking the power turn on transient into account. But the Krells have a slow system startup.

Could i change the Phase#3 braker from 40 to 70Ampere and reduce the phase 1 and 2 lines?

Luvin Da Blues
02-23-2009, 07:11 AM
I'm just heading to work so for a short reply;

Is the power feeding these circuits on one cable? If it is then the breaker will need to be a three pole, pretty hard to change just one pole on the breaker. Another point, unless the wiring is rated for 70 amps then DO NOT do it unless of course you like to roast marshmallows..

I would have an electrician install isolated and dedicated outlets to your requirements. I could use a trip to Europe, nudge nudge wink wink.

Florian
02-23-2009, 07:17 AM
Thanks for the reply!

They are three phases, each with a 40Ampere braker. We will change the cable accordingly. You are a bit far away, otherwise i would have picked you up :-)

Luvin Da Blues
02-23-2009, 05:38 PM
One thing you may consider if your having 'lectric werk done. Install a dedicated audio breaker box close to your gear. Also have the feeder cable to this panel run thru a 1 to 1 transformer for complete isolation from the rest of the building. I would also have them wire it up with isolated (insulated and dedicated) ground wires (similar to hospital receptacles).

But that's only of course if I had yer coinage. Hope this helps.

Cheers,

LDB

Florian
02-24-2009, 11:42 PM
Thanks for the tips!

I am going to increase one phase from 40Amps to 80Amps and hold the entire system on one phase.

Kevio
02-25-2009, 06:49 AM
It is best to keep power usage balanced on your three phases. If you don't, you'll have excessive current on your ground circuit. Ground loops are more of a problem when more current is flowing in ground circuits. There is no intrinsic "ground loop" issue with equipment operating on different phases - all three phases use the same ground.

hermanv
02-28-2009, 09:58 PM
Hi guys,
<snip>
So in total i need at least 62ampere on 230volt (124ampere on 115volt) that is without taking the power turn on transient into account. But the Krells have a slow system startup.

Could i change the Phase#3 braker from 40 to 70Ampere and reduce the phase 1 and 2 lines?

Hi Florian;
That's 14,950 watts, even at 50% that would equal 7,475 watts, what are you filling? A stadium?

Chances are those current ratings are inrush or peak, your ears wouldn't last at that power level.

If you must. I agree about a dedicated line, wire it for that kind of current. Luckily I'd guess that for you, cost is not a serious consideration