Damage to luminaires

[Heptagon]

We have had several lighting units (profiles and fresnels) out for repairs for several months (from a shared venue).

 

The repairers have stated that they have been plugged into dimmed 240v power, and this caused the damage.

 

Two questions - 1. What is the effect of plugging a DMX-controlled lighting unit into a dimmer output?

 

2. Why would anyone do such a thing?

 

(they apparently hadn't been removed from the theatre rig so the dimmer would have had to be patched into the distribution system).

[david.elsbury]

This is another very vague post from you. Profiles and fresnels are generally fine to plugged into a dimmed feed.

What units exactly do you have?

 

In relation to question 2; people suck. Unless you can find the person who did it and ask them you’ll probably never know.

[gyro_gearloose]

It’s not that vague really. The other thread was about LED profiles and Fresnels, so it’s probably safe to assume that this one is too.

 

I don’t know what cabling arrangements you use in Australia, but here in the UK dimmed power usually uses 15A plugs, while hard power for movers/LEDs/etc. use 16A Ceeforms. If you use the same type of plug for dimmed and hard power then you run the very real risk of plugging intelligent fixtures into dimmers, which is probably what has damaged your fixtures.

 

As for what damage has been done, hopefully it’s just the internal power supply. If you have a working fixture identical to the damaged ones, I’d try swapping over power supplies, if that’s possible, to narrow down exactly which parts are damaged.

[mac.calder]

Theatres in Australia will tend to use a standard Australian domestic connector. Some theatres will use 20A or 15A sockets for patchable power, which readily accepts 10A plugs - as the only difference in a domestic 10, 15 and 20A plug is the size of the earth pin - so 10A will fit in 15A and 20A sockets, but 15 won't fit in 10A and 20A wont fit in 15 etc.

[Jivemaster]

The internal electronic power supplies in LED, and discharge fittings tend to die when fed with power from a dimmer. Probably if they are cheap Chinese lanterns then they are scrap when the PSU fails, maybe there will be someone who has the interest and the parts locally enough to you to do repairs.

 

This is (at least part of) the reason why in the UK, hard power may well be found on Ceeform outlets and dimmed power may be found on 15A outlets.

 

Anywhere that you send DMX to a bar you need to send hard power. Painting your connectors differently for hard and dimmed power may help in the future.

[Stuart91]

the only difference in a domestic 10, 15 and 20A plug is the size of the earth pin - so 10A will fit in 15A and 20A sockets, but 15 won't fit in 10A and 20A wont fit in 15 etc.

 

At the risk of sidetracking the thread, how does that work? I'd expect that a 10amp earth pin would rattle around in a 20amp hole?

 

Do you have fuses in the plug top itself? (Like the UK 13amp plug). If not, what prevents, say, an overloaded multiway extension with a 10amp plug drawing 20amps from the outlet and melting?

[Heptagon]

The Australian 3 pin plug/socket has flat pins, and the only difference between 10 and 15 amps is the earth pin - marginally thicker, but significantly wider for 15 amps.

 

A 10 amp plug fits into a 15 amp socket, but not visa versa.

 

The rig uses all standard-type 10 amp plugs and sockets.

 

The theatre has only "hard" power connected, so the culprits (unknown) must have either removed the units from the battens, or insinuated their own dimmer into the rig.

 

Sorry for the vagueness - they are led profile and fresnels. I don't have the actual model numbers, but they are PLProfile and PLFresnel units (LED).

[Don Allen]

There is a need to clearly identify stage lighting outlets in Australia, because we use the same 3 pin plug for power and lighting. There used to be a convention of using round earth pin sockets for lighting as lighting had a different tarrif or price, but that is no longer done. What people refer to as a 10A socket or power point has 16A rated components inside, so the only noticeable difference between a 10A and a 15A socket is the wider earth pin, as our earth pins are designed to handle 2.5 times the rating of the active conductor, to ensure that the circuit protective device, which could be a fuse or circuit breaker, disconnects the load in a fault situation. Australia does not have fused plugs and rarely will you see a fuse in a conventional stage lighting fixture.

 

I Australian theatres the lighting sockets are not usually switched, or use auto switching sockets in some installations. When a standard power point is used, there is a risk that the switch is left off so the outlet will not work and has to be accessed to switch it on. The lighting outlets should have a circuit number on them to identify the lighting socket so it can be patched into a dimmer or hard power. Jands lighting bar

 

It is up to the theatre to clearly identify what circuit is patched into a dimmer or hard power, this is usually done with a patching schedule, which can be soft patching on a lighting desk as there are several brands of combination dimmed and power distribution units made and sold in Australia.

 

The list of lighting equipment that can be damaged by powering it from a dimmer include LED's, moving head lights, scanners, effects lights with switch mode power supplies.

 

As to why anyone would want to do such a thing, answers include lack of training, lack of supervision, lack of exclusion of the public from dimmer rooms and lighting catwalks and facebook. There is a lot of misinformation and antisocial attitude on the facebook lighting pages I have looked at.

[paulears]

Any socket is a usable socket - is the mantra of everyone who is NOT a lighting person. I found yesterday a good example. While we were all at lunch, a group of dancers needed to plug in a small amp, and their computer to play some music, because the sound op was with us. Should have been a break, but wasn't for them. 4 way 13A strip, with a 16A plug. They'd found a cable with a 16A socket going to a 15A plug, and were happily playing their music when we got back. By sheer luck, they had plugged it into the one obvious socket near the computer - which luckily was hard power! every other 15A would have been from our dimmers. You can't expect people to understand this. Switch mode power supplies really don't like being dimmed!

[DrV]

The Australian 3 pin plug/socket has flat pins, and the only difference between 10 and 15 amps is the earth pin - marginally thicker, but significantly wider for 15 amps.

 

A 10 amp plug fits into a 15 amp socket, but not visa versa.

 

The rig uses all standard-type 10 amp plugs and sockets.

 

The theatre has only "hard" power connected, so the culprits (unknown) must have either removed the units from the battens, or insinuated their own dimmer into the rig.

 

Sorry for the vagueness - they are led profile and fresnels. I don't have the actual model numbers, but they are PLProfile and PLFresnel units (LED).

Those models are Selecon (Philips Entertainment). The PSUs have power factor correction on the input so might be more prone to damage from dimmed power. The PSUs are a bit fiddly to replace but not impossible in the field. They are an off-the-shelf part but I'm afraid I can't remember the details. You just need to have a look at one and search for the part number on the web

[rmstagelight]

Don, what a great description of our theater electrical patching here in Australia.I think the Brits really have a much better system than we do.

With more and more LED fittings and movers making up even simple lighting rigs now, people seem to want more hot power and less dimmer power for events. We really don't have a great system for distinguishing between the two in some cases I don't think.

[andy_s]

I think it's worth pointing out that the system described as 'British' is by no means universal, there are certainly places where you find 16A used for dimmers so you shouldn't go into a theatre and assume 16A equals hard power,always check with the locals. There have been many conversations about getting rid of 15A connectors, though personally I prefer them...

[Jivemaster]

Unless your venue is single use, with a single responsible crew available for all users, then you must assume that any possible (however improbable) arrangement will be plugged in and damage may well occur.

 

IF (as) you say multi use then really you should find a suitable way to prevent anything being connected where it shouldn't be. Bizarrely the item most damaging to a dimmer channel is (IMO) a mirror ball motor it's a tiny load maybe 25w but it's extremely inductive and triacs just die, If you even may possibly have a mirror ball then fit a hard power supply in the right place NOW!

[Charlotte_R]

It's not that vague really. The other thread was about LED profiles and Fresnels, so it's probably safe to assume that this one is too.

 

I don't know what cabling arrangements you use in Australia, but here in the UK dimmed power usually uses 15A plugs, while hard power for movers/LEDs/etc. use 16A Ceeforms. If you use the same type of plug for dimmed and hard power then you run the very real risk of plugging intelligent fixtures into dimmers, which is probably what has damaged your fixtures.

 

As for what damage has been done, hopefully it's just the internal power supply. If you have a working fixture identical to the damaged ones, I'd try swapping over power supplies, if that's possible, to narrow down exactly which parts are damaged.

 

I rarely come across 15a power at the moment. Most stuff I do is live events where everything is on 16s, or places with smart dimmers that can change between hard, dimmed, switched power etc. They're the tricky ones, I suppose, because they mean that a socket can be any kind of power and change from event to event.

[Jivemaster]

And even fully on triacs leave waveform distortion that may well cause problems. It's not hard power if you haven't heard the contactor pull in. A mirror ball motor will take out even a fully on triac channel