Non-dim setting good enough for movers?

[Chris Pflieger]

I know this has come up before, but most of the threads were around a particular Colortran module.

So, if I have (NSI) Leviton NDS dimmers, would the non-dimmed setting be OK for using a moving LED head? Everything I see list this setting as producing non-regulated (dirty) power, therefore the SSR will be driven with a solid on signal, so it should be OK.

Any experiences with this dimmer?

 

[SteveB]

Short answer is no.

Long answer can be found in a search here on CB

https://www.controlbooth.com/search/3034010/?q=Movers+on+non+dim&o=relevance

 

[Chris Pflieger]

Ugh. So much FUD and anecdotal evidence.

First, I've filtered out HID examples as I believe LED ML's are a whole different animal. Second, it seems like "non-dimmed mode" varies from mfgr to mfgr. Third, I really wish there was details attached to the claims that it "blew up my ML's".

I've done a few triac and IGBT dimmer designs (currently revising an IGBT design I've inherited at work), so I'd really like more of a technical explanation than, "the sine wave is modified". As an electrical engineer, I highly doubt the "SCR can't turn on till 20 volts theory. Is it the choke limiting current draw? Oscope captures would be great. Maybe I'll get some...

In my situation, I'd be putting less than 2A draw and the devices are rated for 100-240 VAC (i.e. switchmode power supplies). All the wires are run from knockouts on a rack of 12 channel dimmers to edisons on the pipe, so rewiring would a pain.

Does anyone make a rack mount DMX relay module?

A thought occurred to me: why don't I use the dimmer (non dim mode) to drive a 110 VAC contactor(s)? It'd be a lot cheaper.

 

[soundlight]

Doug Fleenor Designs rackmount relay: http://www.dfd.com/6r15.html

 

[Amiers]

If you have power at the rack and your homerun comes to the rack, Why not just swing a few of the circuits to a breaker and be done with it?

 

[Chris Pflieger]

If you have power at the rack and your homerun comes to the rack, Why not just swing a few of the circuits to a breaker and be done with it?

Because then they are hardwired on and the mfgr. recommends turning them off when not in use; they will typically only be used on Sundays from 8 am till 12 pm.

 

[sk8rsdad]

Ugh. So much FUD and anecdotal evidence.

It's a forum, all opinions are welcome, most are unfiltered, and everything is anecdotal. If you want a definitive response for your fixtures contact the manufacturer. ETC supports running their LED products on a dimmer:

ETC's Selador series LED fixtures are designed to be capable of running on a dimmer in switched mode so, within the ETC family of LED products, no damage will be caused as long as the fixture is not powered at a dimmed state.

The article also answers some of your questions, albeit not for the dimmers you have.

There are 2 primary failure modes when powering MLs and electronic devices through dimmers: zero-crossing detection faults and ballast failure. The former can cause grief for switched-mode power supplies and circuits powered by said PS. The latter can lead to all sorts of heat-related and/or physical faults depending on just how catastrophic the ballast failure is.

Inrush current can cause grief for the dimmer, the ML, or both, as can the limiting of inrush current by the choke in the dimmer.

Feel free to Google for scholarly articles.

 

[JohnD]

Ugh. So much FUD and anecdotal evidence.

As far as going to the manufacturer here is what it says in the Leviton DDS manual:

Here is an example for a moving light, here I chose one from Blizzard, others are similar.

Instead of a rack mount relay, you might also consider the ETC ColorSource relay.
https://www.newlighting.com/28216/new-etc-colorsource-hardwired-dmx-relay

 

[PeteEngel]

With dimmers, even in non-dim mode, never run a electronic ballast from that power. Only used relay power from a panel, or a dedicated relay module from a rack unless SPECIFICALLY approved by both the dimmer and fixture manufacturer. There are too many variables that come into play that can be adversely effected by sending a modified or incomplete sine wave to an electronic PSU.
Or you can not take anyone's advise and do it. Your belief that LED ML's are different should work when requesting warranty repair from the manufacturer.
Just sayin'. Anecdotally.

 

[Chris Pflieger]

A
Instead of a rack mount relay, you might also consider the ETC ColorSource relay.
https://www.newlighting.com/28216/new-etc-colorsource-hardwired-dmx-relay

I like that. 16A rating and relatively inexpensive.



And like I said in my introduction, I know just enough to be dangerous.

 

[Chris Pflieger]

FWIW, we've been running a large fluorescent load off these dimmers in non-dimmed mode. I don't know if they're magnetic or electronic ballast.

And the Leviton data sheet refers to the NDS series as dimmer/relay... I wish I could find a schematic.

 

[soundlight]

I cannot recommend the ColorSource Relay enough. Fantastic little product that will simply turn on the fixtures when you give it data - so when your console is on, your fixtures are on. Console off? Fixtures off. Really well built, too, as with anything ETC.

 

[JohnD]

I like that. 16A rating and relatively inexpensive.



And like I said in my introduction, I know just enough to be dangerous.

There is one GOTCHA with going by the rating, sure, you can daisy chain power from one relay to multiple fixtures BUT you have to check the manual for all fixtures in that chain. Many of the lower cost fixtures may have PowerCon in and out but internally they are wired with too small wire, that is why the fixture may have limits well below the power rating for the connectors.
As far as knowing just enough to be dangerous, at least you are asking questions and listening to the answers. That is the smart thing to do.

 

[JD]

I highly doubt the "SCR can't turn on till 20 volts theory. Is it the choke limiting current draw?

This is a problem created by the nature of the firing circuit which derives its power from the series connection with the load. Inside a SSR is a photocuppler. Basically, a photosensitive transistor or photosensitive triac is wired through a full wave rectifier, current limiting resistor and capacitor to the gates and MT2s of a pair of back to back SCRs inside a potted module. Enough voltage must be present between MT1 and MT2 for this circuit to operate. Because this circuit exists between the line input and the load output, in cannot operate with 0 volts across it as the waveform crosses between halves of the AC waveform. If the firing signal came across the photocuppler at the 0 voltage cross point, the SSR would not switch into conduction. So, the firing signal is delayed until there is some voltage across MT1 to MT2. Because of this, the front portion of the output waveform is missing. This squaring off on the front of each half can cause problems with some electronic and magnetic ballasts, as well as electronic power supplies.

In addition, some dimmers regulate the maximum voltage output to a preset level such as 120 volts. If the input voltage is higher (lets say 127 volts) the dimmer control circuit would automatically dim the output to produce the equivalent of 120 volts even when set at 100%, further distorting the waveform.

 

[BillConnerFASTC]

I cannot recommend the ColorSource Relay enough. Fantastic little product that will simply turn on the fixtures when you give it data - so when your console is on, your fixtures are on. Console off? Fixtures off. Really well built, too, as with anything ETC.

Plus one. And soon it will be addressable I hear - with a DMX address.

 

[cdiamondz]

Plus one. And soon it will be addressable I hear - with a DMX address.

So effectively a relay module in line with fixtures that are being fed straight building power? That's pretty cool!

 

[Amiers]

Because then they are hardwired on and the mfgr. recommends turning them off when not in use; they will typically only be used on Sundays from 8 am till 12 pm.

Turn the breaker off when not in use?

 

[BillConnerFASTC]

So effectively a relay module in line w. ith fixtures that are being fed straight building power? That's pretty cool!

Yes. Wired or wireless. Looking at just distributing power from a plain panel, and plugging in wireless relays each good for up to 10 CS fixtures. Switched power and a DMX universe wherever needed. Extremely low infrastructure costs. Move all now portable gear to an equipment contractor and avoid EC markup on stage lighting.

 

[JD]

One last note. There are relay modules and then there are relay modules.
The ones you wand actually make a click as the electro-mechanical relay slams shut. There are some who make non-dim triac/SSR based modules and call them "relay" modules. These suffer from the same problem that standard dimmers do, a loss of the front of the waveform before the thrysistor can be gated.

 

[RonHebbard]

One last note. There are relay modules and then there are relay modules.
The ones you want actually make a click as the electro-mechanical relay slams shut. There are some who make non-dim triac/SSR based modules and call them "relay" modules. These suffer from the same problem that standard dimmers do, a loss of the front of the waveform before the thyristor can be gated.

I'm not sure how you're ever going to get through to this 'modern' world John but PLEASE don't stop trying. Some manufacturers have taken to calling real relays - air gap relays which can still be misinterpreted by some. Somehow we've got to find a way to 'hammer it home', solid state devices; be they SCR's, TRIAC's, FET's, IGBT's are not synonymous with old fashioned, mechanical, relays. 'Magnetic reed' and / or 'mercury wetted', yes. Solid state devices, no. Please continue your efforts John.
Toodleoo!
Ron Hebbard.