208v. Moving Lights Power Two-fer
- Thread startermstutzman
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mstutzman
Member
By two males I'm assuming you meaning pulling legs from 110v. edisons? Nope. Just using a 208v/3Φ service and wanted to make sure it is ok to use a two-fer for more than one light. I'm sure that a dedicated distro would be ideal, however we have yet to run more than (1) 208v. fixture in the past. Might be something to look into for the future. Thanks for your help!
Last edited:
chawalang
Well-Known Member
If you are going to be using these fixtures a lot I would not two fear them. It is better on lamp life and output quality, I have discovered over time. It all depends on the application and how often they will be used. There is no safety issue as far as two fering them to the same circuit ad long as you do what sound man said.
What? How? Mathematically there is no reason for this to be the case... especially in the world of auto sensing power supply's we currently live in.
There is nothing wrong with using twofers. It can get inconvenient though, if you use many of them in large rigs. Sometimes a fixture has an issue and needs a hard reset(cycling power via the breaker). The problem becomes, now you have to cycle two fixtures, and one is working just fine.
This becomes a further problem if one fixture has a mechanical issue, like a bad tilt belt, and needs to be shut off for the rest of the show; you end up loosing two fixtures rather than one.
There are pros and cons. With the low draw of LED's many fixtures already daisy chain power, and are subject to the same drawback as twofering, but usually the
convenience and the savings on running cable, outweigh the minor drawbacks.
Another downside to twofers is that stage hands often cannot grasp simple concepts, like "Twofer the LEDs, individually circuit the Moving Spots." You will notice pretty quick if someone did it wrong. You also may have to consider, how much you are loading each circuit, load balance, and de-rating soco cable. You should always consider these things, but it can be easy to loose track if you pass out a trunk full of twofers to a bunch of stagehands.
Had someone twofer 2-circuit 8lites Moles once (5200 watts), they actually ran for about 5 seconds before tripping the 2.4K breakers.
This becomes a further problem if one fixture has a mechanical issue, like a bad tilt belt, and needs to be shut off for the rest of the show; you end up loosing two fixtures rather than one.
There are pros and cons. With the low draw of LED's many fixtures already daisy chain power, and are subject to the same drawback as twofering, but usually the
convenience and the savings on running cable, outweigh the minor drawbacks.
Another downside to twofers is that stage hands often cannot grasp simple concepts, like "Twofer the LEDs, individually circuit the Moving Spots." You will notice pretty quick if someone did it wrong. You also may have to consider, how much you are loading each circuit, load balance, and de-rating soco cable. You should always consider these things, but it can be easy to loose track if you pass out a trunk full of twofers to a bunch of stagehands.
Had someone twofer 2-circuit 8lites Moles once (5200 watts), they actually ran for about 5 seconds before tripping the 2.4K breakers.
porkchop
Well-Known Member
I would cautiously say this is probably OK, but I wouldn't say it is always fine.
If you're using a relatively modern fixture (say came out in the last 10 years) from a big manufacture the power switch is probably also a breaker that functions as over-current protection for the fixture regardless of the input's rating. If this is the case, and you've double checked your user manual to make sure it mentions that the switch is a breaker or it has a similar over-current protection device (like the fuses in Mac 2000's), then yes, it's perfectly acceptable to split up your supply power however you desire provided you won't be pulling over the input's breakers ratings and your phases are balanced.
If however you're using cheap Chinese knock-offs, older fixtures (VL1000's are the newest fixtures I can think of that I don't believe have built in over-current protection), or you can't be sure that the fixture is able to prevent an over current situation then you'd need to provide some way to prevent the fixtures from pulling more power than they're rated for.
If you're using a relatively modern fixture (say came out in the last 10 years) from a big manufacture the power switch is probably also a breaker that functions as over-current protection for the fixture regardless of the input's rating. If this is the case, and you've double checked your user manual to make sure it mentions that the switch is a breaker or it has a similar over-current protection device (like the fuses in Mac 2000's), then yes, it's perfectly acceptable to split up your supply power however you desire provided you won't be pulling over the input's breakers ratings and your phases are balanced.
If however you're using cheap Chinese knock-offs, older fixtures (VL1000's are the newest fixtures I can think of that I don't believe have built in over-current protection), or you can't be sure that the fixture is able to prevent an over current situation then you'd need to provide some way to prevent the fixtures from pulling more power than they're rated for.
