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When to 3 phase?
Dave Guilford:
Been renting small MQ15kVA generators for a few years. Got lined up at another rental co and the smallest they offer is a 25kVA. Same price too, and about 30 mins closer to their shop.
Their 25kVA has 3-phase option. When / why would I do that? What benefits do I get from 3 phase versus regular ass 1 phase.
And what about 240 vs 120. I think virtually all my gear is “universal power supply” type where it’ll take 100-250v or whatever.
Teach me.
TJ (Tom) Cornish:
--- Quote from: Dave Guilford on June 26, 2018, 11:14:13 AM ---Been renting small MQ15kVA generators for a few years. Got lined up at another rental co and the smallest they offer is a 25kVA. Same price too, and about 30 mins closer to their shop.
Their 25kVA has 3-phase option. When / why would I do that? What benefits do I get from 3 phase versus regular ass 1 phase.
And what about 240 vs 120. I think virtually all my gear is “universal power supply” type where it’ll take 100-250v or whatever.
Teach me.
--- End quote ---
What did Guitar Center say?
John Daniluk (JD):
the 25kw will give you more amperage in single phase than you have now. 3 phase gives you 1/3 more amperage to use.
Basically if a generator is 3 phase the KW power is rated for 3 phase. When you set it for single phase you loose one leg of power or 1/3 of your available amps.
For example a generator rated for 25kw at 3 phase is a basically 70 amps per phase giving you 210 total amps. when you change the generator to single phase you have around 140 amps available for use. ALL of this is depends on how the generator monitors the legs for over current and voltage.
If you change your equipment to 208v I think you will be changing them back and forth for smaller shows. Leave them at 120v and get a AC distro. If you get a 3 phase distro, mark which outlets are on each phase. This helps when you can only get single phase.
I have I did not confuse you....
jd
Dave Guilford:
Great reply and thank you. The last thing you mentioned was building distro for 3phase.
But when I use it for single phase, as you mention, what happens? “When you can only get single phase power”. Does that mean 1/3 if my outlets won’t work?
Dave Guilford:
But basically the answer to “when to 3-phase” is “whenever you can”.
I’ve been renting from UR and Sunbelt and the like. They provide those ugly yellow spider boxes. Those probably don’t denote which circuits are on which legs, do you suspect?
Usually it’s california type 50a feeder
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