3 phase dimmers on 1 phase service??

[chausman]

...I never really did understand ETC's 2 Dimmers on one module thing.

Do you mean having dimmers 1+2 on a single module, or using dimmer doublers?

Having 2 dimmers on one module just makes things easier by going in pairs. Less moving parts by having fewer things going in and out of the rack. Less cost by having to buy fewer dimmers.

If your talking about dimmer doublers...set them down, leave them alone, and don't make eye contact...just back away slowly...no one fully understands the dimmer doublers.

 

[rphilip]

Someone doesn't like red I guess. Usually, blue is the color left behind. Single phase it is. (or two of three)

This is only a guess but might the reason that red is not being use be that red is the middle color and for a split phase rack 1/2 of the middle 1/3 is moved to each of the other thirds?

ie normally it's 1-8 on black, 9-16 on red and 17-24 on blue. For split phase I'd guess that 9-12 are rebussed to the upper lug (black) and 13-16 moved down (to blue)

Philip

 

[cdub260]

If your talking about dimmer doublers...set them down, leave them alone, and don't make eye contact...just back away slowly...no one fully understands the dimmer doublers.

Hey! I like my dimmer doublers!

 

[lightingguy1]

Do you mean having dimmers 1+2 on a single module, or using dimmer doublers?

Having 2 dimmers on one module just makes things easier by going in pairs. Less moving parts by having fewer things going in and out of the rack. Less cost by having to buy fewer dimmers.

If your talking about dimmer doublers...set them down, leave them alone, and don't make eye contact...just back away slowly...no one fully understands the dimmer doublers.

Let me Rephrase that a little - I never did understand the ETC's Circuit calulation thing.

i.e. - "ETC 24 x 2.4k with CEM+ Portable Pack" - From 4wall's site

The 24 part, in my mind, is the number of modules, not the total amount of circuits available on the rack itself. Not so!

 

[chausman]

Hey! I like my dimmer doublers!

Never said they weren't useful, just that they are more mystical and magic then DMX...and Microwave Popcorn!

 

[lightingguy1]

As far as the Dimmer doublers go, I might have to use some! In the Current show, I am wanting to hang a few more systems of Backlight

Or steal the Chauvet Colorado Batten 72 Tours we have in the closet down the hall!

 

[derekleffew]

...The 24 part, in my mind, is the number of modules, not the total amount of circuits available on the rack itself. Not so!

See what I mean?

Btw, I'm the generation that mentally overcomplicates things

Ah, but in the case of Sensor, each module can be 2, 1, or 1/2 dimmers. So the number of dimmers and their size is really the important part. While the model number may be SP12, calling it a 24x2.4kW dimmer pack is more useful, IMO.

 

[Dionysus]

It looks like a single phase setup to me, that or a two phase which I'm not sure its possible to use on dimmer racks I know some higher horsepower electric motors can use two phase.

There is no such thing as "two phase", either "single phase" or "three phase". Having one or two 'phases' present is still called "single phase". What you are referring to are separate voltages, 120v 240v and 220v (we'll ignore 347v, 208v, etc). 240v and 220v require two opposing phases, and 220v requires a neutral.

These dimmers only utilize 120v. As mentioned already each 'phase' or 'hot leg' is divided to an equal proportion of the dimmers (and sharing the same neutral), giving them each 120v.

A good example of common 'true' 240v or 220v loads would be larger electric motors or electric heating elements. They work much more efficiently at these higher voltages than at 120v.

 

[tmm61]

great pics.

the picture of the main breaker (labeled service discount) also says it all: 4 sections with a tie handle -- this has been a "standard" configuration with some manufacturers in the past for a 200amp single phase 240/120volt main panel. (two 200amp 120 volt phases).

(several posters might owe the "somewhat head electrician"/ "janitor" an apology--many/most building electricians do have a basic understanding of their power systems, even if they do not understand the equipment we have rented or brought in)

no offense to anyone.

 

[Chris15]

There is no such thing as "two phase", either "single phase" or "three phase".

Well actually... there is. It's just confined to academia becuase it has no practical usefulness. A true 2 phase system would be a sinusoid and a cosinusoid.
But zero practical use in the *real* world except possibly the aforementioned odd motor. Real motors would use 3 phase IMHO.

 

[JD]

Well actually... there is. It's just confined to academia becuase it has no practical usefulness. A true 2 phase system would be a sinusoid and a cosinusoid.
But zero practical use in the *real* world except possibly the aforementioned odd motor. Real motors would use 3 phase IMHO.

Just ask Frank Stallone's road crew! (see my post above http://www.controlbooth.com/forums/...phase-dimmers-1-phase-service.html#post216546 )

There's two legs there, but they're happening at different times.

 

[Dionysus]

Well actually... there is. It's just confined to academia becuase it has no practical usefulness. A true 2 phase system would be a sinusoid and a cosinusoid.
But zero practical use in the *real* world except possibly the aforementioned odd motor. Real motors would use 3 phase IMHO.

lol, true enough. However I was 'ignoring' such a system, as you really don't see them in real life and talking about stuff like that just gets too confusing for most people.

lol if only all motors were 3-phase. There are so many bloody types of motors, lol.

 

[bishopthomas]

(several posters might owe the "somewhat head electrician"/ "janitor" an apology

Sorry, Janitor Joe. You always make the best electrician in the whole wide world...

 

[lightingguy1]

Hi guys,


Let me see if I get this Bi-phase concept.

ETC's Smartmodule 2 Dimmer Packs (Bi-phase models) and Leprecon's ULD Series dimmers (those that are the high power models), require two power connections, or 2 Hots, 1 neutral, and 1 ground wire for the ETC stuff, for operation...and we call this Bi-phase?

But we Pros call the second line a phase?...So Phase A and B?


Thanks!
-Lightingguy1

 

[mstaylor]

Two hots, nuetral and a ground is a single phase. It is 110v per leg and fire 180 degrees from each other. They are called legs when added together makes 240.

 

[derekleffew]

...Let me see if I get this Bi-phase concept.

ETC's Smartmodule 2 Dimmer Packs (Bi-phase models) and Leprecon's ULD Series dimmers (those that are the high power models), require two power connections, or 2 Hots, 1 neutral, and 1 ground wire for the ETC stuff, for operation...and we call this Bi-phase?

ETC is the only source where I've seen the term "bi-phase" and only recently, on the spec sheets for the SmartModule, as you have noted.
"Single 12/4 SO cable for 120/240V single (bi/2) phase feeds"
"4 circuit SmartModule 2, Bi-phase (2 x 20A) Single Cable in, Stage Pin Out"

The phrase "split-phase" is also relatively new (~10 years old?), but more universally accepted, and needed in an attempt to avoid confusion between 1Ø 120V, and 1Ø 240V.

As said above, with 1Ø 240V, the wires are usually identified as L1, L2, N, G.

 

[lightingguy1]

This is good!

Now we're getting somewhere!! And what type of Connector would a "Bi-phase" Smartmodule dimmer require?

 

[derekleffew]

And what type of Connector would a "Bi-phase" Smartmodule dimmer require?

The most common for stage use is likely a NEMA L14-20:

But any UL Listed, 3P4W 20A 125/250V connector would be acceptable, which is why ETC makes the user supply his/her own.

 

[TimMiller]

One trick I have done when you have two 3 phase dimmers or distros on a single phase service is alternate the legs. Leg 1 will go to line 1 leg, leg 2 will go to line 2, leg 3 will go to line 1, in the second rack leg 1 will then go to line 2, leg 2 will go to line 1, then leg 3 will go to line 1. It keeps the loads fairly balanced and also works the other way around. I don't like opening up a dimmer rack and rearranging the jumpers if I can avoid it.

 

[DavidNorth]

I'm a little surprised that someone from the UK or EU hasn't joined in on this one....

ETC has decided to start calling things bi-phase [same as split-phase] for a very good reason. In the UK, for example, when you talk about a single-phase service, it is only one phase of power. In the US, single-phase usually means two phases of power at 180 degrees apart, but not always.

In order to reduce confusion and get product documentation and orders straight, while still being technically correct, we have gone to bi-phase.

So on another topic [which was mentioned earlier in the chain], not all dimming systems on the market sample each incoming phase of power to derive their firing signals. There are a few bi-phase and three phase inexpensive dimming products that require the correct phasing and phase order of power to correctly dim. Just thought I would throw that out there to chew on and be aware.

BTW, there are two-phase and four-phase systems out there. They're just not that common.

David