Using 208v with rogue LEDs

[koimystic]

I own R2 washes, R2 spots, RH1 hybrids, and ovation 160ww fixtures. I have always run them on 110v but planning to begin powering them on 208v 3ph or occasional 220v single phase. I understand the power supplies are auto self switching. However do I need to install a different fuse in the fixtures since they will be running higher voltage and less amps? When converting the powercons to 208/220v I just need to convert the neutral wire to a hot wire on a separate phase/leg? Any other thing to take note when operating these on 208 3phase or 220v single phase? Down side to 220 single over 208 3?

What happens if the voltage is lower on one leg while using 3 phase?

 

[Colin Bishop]

There is no fuse to switch as it is an auto-ranging power supply that will work with any voltage from 100 to 240 VAC. I believe the powercons need no adjustment, you just need to switch the end on the plug to whatever 220volt plug you are using. How to wire that, you need to know as it would be against Controlbooth rules to instruct you how to wire a plug. As for three phase, this is not a three-phase product nor are there really any other lights except large dimmer racks that use three-phase power natively. Perhaps you mean you will be running this off a three-phase power distro? Which would take three-phase power and distribute it down to 120volt or 220volt single phase.

 

[FMEng]

We interrupt this program for....

It's probably a losing battle, but I'd like to correct the nomenclature here. There's no such thing as "220" in the United States. Single phase is 120 /240 V. The voltage of 220 derives from AC motors which list the minimum applicable voltage to obtain the nameplate horsepower, not the normal voltage. That's also where the common numbers 110, 115, 117 and 230 come from, the world of motors.

Now back to the regularly scheduled discussion....

 

[RickR]

Why?? As @Colin Bishop noted they are a single phase unit. Your supply will likely be either 120/240 single phase or 120/208 3 phase and using only part of a 3 phase supply does bad things up the line. 120V is the common element! If it's an issue of having 3ph available then get something to break out 3- 120V lines and go from there. Like this: http://www.lexproducts.com/products/entertainment/powerhouse-portable-distribution-boxes/20-30-amp-portable-distribution-boxes/20-amp-3-phase-gang-box

Playing games with the voltage just changes the amperage but leaves the power draw the same. You could run longer distances or more units with the same size cable, but you'd have to use all 208V rated plugs and cables. As they draw so little power it probably isn't much of an issue.

As too many folks haven't noticed; plugs are rated and built for certain supplies. This is a major safety point that should not be defeated. It keeps you from plugging 120V gear into 240 or 208, and visa versa, or other silliness. If you really need to use 3 different sources you would need 3 different power-con tails each with the appropriate plug. Or you'll be spending lot's of time re-wiring stuff.

 

[FMEng]

Why?? As @Colin Bishop noted they are a single phase unit. Your supply will likely be either 120/240 single phase or 120/208 3 phase and using only part of a 3 phase supply does bad things up the line.

Huh? In buildings with three-phase service, where do you think the power for all the 120 Volt loads comes from? Running single phase loads from one or two phases is done all the time and doesn't hurt a thing as long as the total loads in the building are reasonably balanced across all three phases. Odds are the LED lights are a drop in the bucket and won't affect phase to phase balance in the least.

The truly three-phase loads in most commercial buildings are typically limited to the large blowers, pumps, and compressors in HVAC, elevators, and large resistance heaters, but everything is fed from three-phase panels.

 

[RickR]

as long as the total loads in the building are reasonably balanced across all three phases.

Just simplifying for an someone with limited knowledge. "Reasonably" is a judgement call, like what is over simplification.

 

[koimystic]

Thanks for the input all. I very well understand the importance of load balancing your legs on 3 phase. I am the guy at every show with the clamp meter balancing loads just because I think its fun... And good practice. But I also agree LED's on the small rigs discussed here is a drop in the bucket. Typically these shows we tie into 400amp company switch with 2/0 feeder on a 400amp rated PD. Excessive? Yes. Typically we only pull 45amps a leg, max.

Rick, you asked what is my goal here? Well we do a lot of small corporate shows with a flown FOH truss for lighting. I am wanting to run a single 12/3 L6-20 cable and power up 8 Ovation LED lekos, 2 Rogue R2 LED Spots, and 4 Rogue R2 LED Washes. As most production companies know, efficient setup/strike and less gear on the truck equals more profit. Doing this I can run 1 cable for power to my lighting truss. Most 12/3 is rated for up to 600v and I have purchased a handful of L6-20 connectors to build some new 12/3 208v cables. I understand the most dangerous piece here is going to become my L6-20 to Powercon cable, if someone plugs into a 120v only rated powercon input device.

My take from this is that I do not need to change a fuse for 208/220 operation. The reason I thought I might is because our powered line arrays require a fuse to be changed if powering them up on 220v.

Are you saying I should not run these fixtures off 2 hot legs+ground from 3phase power (208v)?

Thanks!

 

[derekleffew]

I very well understand the importance of load balancing your legs on 3 phase. I am the guy at every show with the clamp meter balancing loads just because I think its fun... And good practice.

@STEVETERRY says balancing phases isn't important.

Guys--please just relax.

A properly designed three-phase dimming system should be able to tolerate whatever phase imbalance you can throw at it.

100% on A, zero on B & C , why not?

There is no reason to consider phase balance as part of the production check list.

Y'all have bigger things to worry about!

ST

-----

Are you saying I should not run these fixtures off 2 hot legs+ground from 3phase power (208v)?

Sometimes called bi-phase; perfectly acceptable. Although there are occasionally issues where a device (usually a motor) wants a voltage slightly higher than 208V. Had a issue once with long power runs and SyncroLite s needing a buck/boost transformer, but that's pretty much the polar opposite of an LED.

 

[RonHebbard]

Thanks for the input all. I very well understand the importance of load balancing your legs on 3 phase. I am the guy at every show with the clamp meter balancing loads just because I think its fun... And good practice. But I also agree LED's on the small rigs discussed here is a drop in the bucket. Typically these shows we tie into 400amp company switch with 2/0 feeder on a 400amp rated PD. Excessive? Yes. Typically we only pull 45amps a leg, max.

Rick, you asked what is my goal here? Well we do a lot of small corporate shows with a flown FOH truss for lighting. I am wanting to run a single 12/3 L6-20 cable and power up 8 Ovation LED lekos, 2 Rogue R2 LED Spots, and 4 Rogue R2 LED Washes. As most production companies know, efficient setup/strike and less gear on the truck equals more profit. Doing this I can run 1 cable for power to my lighting truss. Most 12/3 is rated for up to 600v and I have purchased a handful of L6-20 connectors to build some new 12/3 208v cables. I understand the most dangerous piece here is going to become my L6-20 to Powercon cable, if someone plugs into a 120v only rated powercon input device.

My take from this is that I do not need to change a fuse for 208/220 operation. The reason I thought I might is because our powered line arrays require a fuse to be changed if powering them up on 220v.

Are you saying I should not run these fixtures off 2 hot legs+ground from 3phase power (208v)?

Thanks!

@koimystic @derekleffew Personally, speaking from Canada, I'm more concerned with you connecting 2/0 feeders directly from a 400 Amp rated company switch without any supplementary protection for your lengths of 2/0 feeder no matter how short their lengths may be.
Toodleoo!
Ron Hebbard.

 

[TJCornish]

There is no issue running any Rogue gear at 208/240v. One of the benefits of Powercon is the Powercon side of the cord can be dual voltage - switching back and forth simply requires changing the input plug (or rather swapping to a different cord with a L14-20 or L6-20 on the male end).

Whether this is a good idea in the grand scheme depends less on code issues and electrical safety (same rules; just pick the right plug and over-current protection device- must be 20A) and more on how the rest of your power distribution is designed. 208/240 allows chaining more fixtures. 208/240 makes heavy loads like large power amplifiers happier.

If it makes sense for your overall power distribution scheme - do it. If it doesn’t, then don’t, as you won’t notice any difference in function of the gear - it does exactly the same thing on 208/240 as it does on 120.

 

[TJCornish]

Why?? As @Colin Bishop noted they are a single phase unit. Your supply will likely be either 120/240 single phase or 120/208 3 phase and using only part of a 3 phase supply does bad things up the line. 120V is the common element! If it's an issue of having 3ph available then get something to break out 3- 120V lines and go from there. Like this: http://www.lexproducts.com/products/entertainment/powerhouse-portable-distribution-boxes/20-30-amp-portable-distribution-boxes/20-amp-3-phase-gang-box

Playing games with the voltage just changes the amperage but leaves the power draw the same. You could run longer distances or more units with the same size cable, but you'd have to use all 208V rated plugs and cables. As they draw so little power it probably isn't much of an issue.

As too many folks haven't noticed; plugs are rated and built for certain supplies. This is a major safety point that should not be defeated. It keeps you from plugging 120V gear into 240 or 208, and visa versa, or other silliness. If you really need to use 3 different sources you would need 3 different power-con tails each with the appropriate plug. Or you'll be spending lot's of time re-wiring stuff.

I wanted to comment on the idea of "using only part of a 3 phase supply does bad things up the line." Other than a machine tool or HVAC fan motor that uses all 3-phases equally, the legs in any 3-phase system are never equal. As was mentioned, that's not necessarily a problem as for resistive loads, any imbalance combination will still result in all conductors being under their design current limits. HOWEVER, reactive loads can create problems.

Reactive loads are devices with some kind of energy storage - either a magnetic field in a motor or coil, or capacitors. This energy storage changes the time relationship between the voltage waveform and current consumption. The result of this is harmonics on the power line, which can in extreme cases overload the neutral wire. This only can happen if you're using the neutral wire - in other words 120v line to neutral loads. Taking that same equipment and running it at 208/240v from line to line removes the possibility of contributing harmonic current to the neutral wire, and is potentially a very real benefit of running gear at 208/240. This has applications when using generators in some cases too.

We are off in the weeds here and the Rogue and Maverick gear is power factor corrected to some degree anyway, but it is worth mentioning.

For what it's worth, I quite like L14-20-based power distribution. You can use it to power a two-circuit 120v 20A breakout box with no downstream OCPD needed, or you can use it as a single 20A 208/240v circuit. You can legally adapt from a male L14-20 plug to a Powercon by omitting the neutral wire (important note - you CANNOT do this in the other direction: Powercon male to L14-20 female is not acceptable), which works great for the situation in this thread.

 

[derekleffew]

For what it's worth, I quite like L14-20-based power distribution. You can ...

(Just to be ornery) Why L14 and not L21? If two is good, three has to be better, right?

 

[TJCornish]

(Just to be ornery) Why L14 and not L21? If two is good, three has to be better, right?

Two reasons:

1. NEC table 400.5(A)(1) allows the use of #12 wire for 3 20A current-carrying conductors. Going up to L21 means 4 current-carrying conductors, which means all the cabling needs to be upsized to #10 even for a 20A load.

2. I do a lot of work in rooms with California or 14-50 stove plugs, which are two-phase (yes I know that's not a thing), rather than 3-phase. With L14-based distribution, all my receptacles work rather than trying to guess which ones will be dead and following my stage hands around repatching things that don't have power.

 

[soundlight]

I use Chauvet gear - Rogues, Ovations, Mavericks, and Colorados - regularly with a mix of 208V and 120V power depending on the gig and the distro. No problems.

 

[EdSavoie]

Just to throw my hat into the discussion, our college does teach us to keep the phases relatively balanced, as well as derating ampacity on three phase systems to avoid overload.

 

[TJCornish]

Just to throw my hat into the discussion, our college does teach us to keep the phases relatively balanced, as well as derating ampacity on three phase systems to avoid overload.

While not disagreeing with your broad strokes, how exactly do you do this? What do you mean by derating? What systems do you encounter where you don't derate (the vast majority of the commercial buildings in the US have 3-phase derived power)?

 

[EdSavoie]

IIRC, we account for 1.6x current in the neutral.

 

[TJCornish]

IIRC, we account for 1.6x current in the neutral.

Is this a fixed install? Touring rack? Only dimmers? Mixed dimmed and electronic loads? That number seems arbitrary to me, and hard to enforce.

If it's a fixed install, it should be rated to run to FTB (full-tilt-boogie) without the need to do math by the end users. The entire NEC (Yes I know you are in Canada) is based on this premise - the calculations are done at install time and the OCPDs are such that the end user can't get in trouble even if the system is overloaded.

Touring systems are harder to nail down and there are some situations where getting in trouble is possible, but with the shift to power-factor-corrected fixtures and increased usage of 208v this is less of an issue, as well.

 

[JonCarter]

Balancing loads on a 3 phase supply sounds good but will never happen in practice. Let's say you figure out which phase A, B or C, each dimmer is supplied by and you carefully connect your instruments such that you've connected them to dimmers such that the loads are almost exactly equal on each phase. You turn everything on with dimmers at "10" (or "0" if you were brought up on piano boards) and measure currents in your three phases and get 495, 489 and 492 amps. Almost perfect! Now run any cue in the show. Some dimmers will be at "10," some at "0" and some in between. There went your "perfect" balance. The only time you ARE in balance is if you bump everything to "FULL" for curtain calls.

 

[RonHebbard]

Balancing loads on a 3 phase supply sounds good but will never happen in practice. Let's say you figure out which phase A, B or C, each dimmer is supplied by and you carefully connect your instruments such that you've connected them to dimmers such that the loads are almost exactly equal on each phase. You turn everything on with dimmers at "10" (or "0" if you were brought up on piano boards) and measure currents in your three phases and get 495, 489 and 492 amps. Almost perfect! Now run any cue in the show. Some dimmers will be at "10," some at "0" and some in between. There went your "perfect" balance. The only time you ARE in balance is if you bump everything to "FULL" for curtain calls.

@JonCarter "The ONLY TIME"? What about when you fade down to your total black out? C'mon at Jon, you know it'd be mere seconds before our proudly self-professed "Resident Curmudgeon" @derekleffew called you out for your all encompassing, sweeping, generalization.
@derekleffew , are you O.K. lad??
Toodleoo!
Ron Hebbard.