Why not lamp it with 230V/240V globes? Then you won't need a transformer.
The lamps should be readily available, because 230V is a common voltage in Europe, and I've even seen some 240V globes.
The Quick 220 Power Supply is not as straight forward as it appears: the two outlets it uses to make 240V must be on different circuits that are out of phase (opposing legs of the electrical service) and not controlled by ground fault interrupters (GFI's). And, if the service is 3 Phase rather than Single Phase, you will get 208V without any means of stepping it up to 240V. At 208V a 240V bulb will look quite dim and very warm.
There are a couple of good reasons why you may still want to operate a 2k at 120V through a transformer/distro rather than directly into a 240V receptacle. First, a 30A/240V dryer receptacle offers you 60A at 120V through a 240-to-120V step-down transformer. If you plug the 2k in through a transformer/distro and operate it at 120 Volts you still have 43.2 Amps left over to power additional lights through the transformer as well if your. That’s a lot of power in an easily distributed form to not take advantage of.
Master shot of an iRobot commercial lit with a 4kw HMI Par (outside) & 1.8kw HMI Par (inside) powered from a 30A/240V dryer outlet through a step-down transformer/distro. Note: Sunny feel created by 4k Par on an overcast day.
The second reason is that if the 2k is far from the 240V receptacle you can have appreciable line-loss (voltage drop) over a long cable run. A transformer/distro can be used to compensate for line loss, as well as the voltage drop on a generator from running it near full load. Our transformer/distros provide variable taps on the primary side that enable you to adjust the step down ratio to boost their output above the standard 2:1 ratio. This boost capacity will compensate for accumulative voltage drop and assure full line level (120V) on set.
Left: Transformer/Distro plugged into a 30A/240V dryer outlet. Right: 4K HMI Par under rain protection powered by Transformer/Distro
This feature of our transformer/distros was a real benefit on a recent commercial for iRobot (see production stills attached.) The spot contrasted the iRobot Scooba designed to clean kitchen floors to the old mop and bucket approach. For the mop and bucket approach we had a haggard looking Mom slopping water all over the kitchen floor as kids ran slipping and sliding across the floor.
Left: Arri AS18 1800W Par powered from Transformer/Distro. Right: 4Kw and 1800W HMI ballasts powered from Transformer/Distro.
The only available source of power for our 4K and 1800W HMIs was a dryer receptacle in the laundry room. Unfortunately, the laundry room was upstairs and in the front of the house and the kitchen was downstairs and in the back. Fortunately, we could use the boost capacity of our transformer/distro to compensate for the 16.5V line loss we experienced after running 300’ of high voltage twist-lock extension from the front to the back of the house. You wouldn’t think there would be that much voltage-drop over a 300’ 10AWG cable run, except that in this case, the electrical service was in the basement under the kitchen where we were shooting. Which means the circuit supplying our lights consisted of approximately 300’ of wire from the electrical panel in the basement under the kitchen to the dryer receptacle upstairs in the front of the house, plus the 300’ of wire we ran back to the kitchen, for a total of approximately 600’ (see voltage drop table below.)
Note: the voltage drop on a 600’ run of 10AWG stranded cable is 16.497 volts
An added benefit to using a transformer/distro in this case was that it enabled us to use a 100A Shock Block to offer GFCI protection for cast and crew. We knew water would get everywhere inside the kitchen, so to protect the cast we put a 100A Shock Block like the one pictured below on the load side of the transformer/distro to provide Ground Fault protection inside around the wet kitchen floor. It was a good thing that we did, because it ended up pouring rain that day and so the Shock Block did double duty for the 4k that was outside the kitchen window.
A single 100A GFCI "Shock Block" can provide ground fault protection on wet locations for the entire distro system of a Honda 6500 portable generator when used in-line with a Step-Down Transformer/Distro.
I regularly use transformers to power not only big HMIs (2.5-4Kw), but also quartz 5ks, in situations where a tie-in is not an option and the budget doesn’t permit for a tow generator. Use this link for more details about using step-down transformers on set. By giving you safe and legal plug-in access to more house power through common 240V house outlets, a transformer can quite often eliminate the need for tie-ins or generators.
Guy Holt, Gaffer, ScreenLight & Grip, Lighting rental and sales in Boston