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Do dimmers need 3-phase power?

Posted: October 5th, 2008, 3:32 pm
by jamess
Hi, I am about to purchase 3 of these: http://cpc.farnell.com/jsp/level5/modul ... 470059.xml

the page info says "3-phase mains supply (1 phase possible at lower output power)"

What does that mean?


Apologies if this is a silly question....

Re: Do dimmers need 3-phase power?

Posted: October 5th, 2008, 6:38 pm
by Mattotone
Well that depends how many lights will you be running.
For full 60Amps of power 3 phase will be required.
Your normal domestic single phase plug can supply up to 13Amp.
13 Amps will allow up to 3200watts.
Roughly about 500W per channel.
I Haven't read the manual so it may not allow that much power on single phase.
some venues have 30Amp c-form sockets available.

Re: Do dimmers need 3-phase power?

Posted: October 5th, 2008, 8:53 pm
by jamess
There'll be 2 300W PAR56 cans per channel on two of them and just a couple of fresnel spots and long spots on the other.

It looks like i'm gonna need a 3 phase supply, is there some kind of inverter i can use?

Re: Do dimmers need 3-phase power?

Posted: October 6th, 2008, 10:02 am
by Mattotone
It depends on the dimmer.
I can't find a manual so can't say.
Your going to find it hard to get 3 phase anywhere, apart from large clubs, arenas or 3phase generators.
3 phase is supplied directly from the grid, there is no magical device to convert 3 phase from single phase.
Most of the electric power in the world is 3 phase. The concept was originally conceived by Nikola Tesla and was proven that 3 phase was far superior to single phase power. 3 phase power is typically 150% more efficient than single phase in the same power range. In a single phase unit the power falls to zero three times during each cycle, in 3 phase it never drops to zero. The power delivered to the load is the same at any instant. Also, in 3 phase the conductors need only be 75% the size of conductors for single phase for the same power output.

Your dimmer may be able to provide more power through a single phase 32amp Cform socket.
But again these won't be that commonly available apart from places that normally accept big names and expect to power large rigs. Most will have 13Amp sockets.
So you may need to buy two dimmers and power them on two 13amp plugs, most ring mains will power more then one socket and generally a ring main will be protected by 32amp fuse.
to run your setup (lighting alone) you will require two separate circuits. Not two separate sockets, but circuits. I.E if you turn one breaker off the other remains on.
If the venue doesn't supply 32Amp Cforms, its more then likely these two circuits will be far apart so expect to carry long, large diameter extension cables and extra time to find different circuits.

but 36 par cans + other lighting + PA will be practical for you to buy a distro.
you will still have the problem that the venue doesn't have 3-phase or a 32amp supply you will require an electrician to tie your distro into the venues power supply.
your lighting supply at 230v requires at least 46Amps of power.

probably best if you consult an electrician and invest in a distro.