Hooking a Follow Spot into a Dimmer

[krhodus]

I am looking for a way to get the cut off times of 2 followspots to be the same. The idea proposed by someone on my lighting crew was run it through our backup Leprechon system. This would be just used for 100% and 0%, nothing inbetween. Can a spot be used like this or will it cause problems for it? The spots would be left on all the time and power controlled by the dimmer. We have 2 Altman Comets that draw 360 watts. Electrically we are running the dimmer out of a 20A 120V outlet, giving 2400W, so overloading is not an issue.

Kevin

[jonhirsh]

I dont know your fixtrues,but if they have a balest or a transformer built in to them then do not hook them up to a dimmer you will kill the fixture. most folow spots have a transformer or a balest so i wouldnt risk it. just have the operators practice till they get it right thats how the rest of the world does it.


JH

[jbeutt]

if it has a balest or not you can go ahead and plug it into the dimmer. Just make sure the channel is set on nondim or whatever which will basically turn it into a switch, so 0%=0% and 1-100%=100%, kapeesh? Otherwise it's fine.

[jonhirsh]

Thats not true you will still damage the balest because it is not 60 cycle a second power that has even peaks it will mess with the inner workings of the balest and anyway he wants to dim out two spots at once.


do not no matter weither you set it to non dim or not plug a follow spot into a dimmer. the same goes for moving lights.

i reapeat do not plug it in, if it has a balest or transformer you will damage the fixture.

JH

[avkid]

In my earlier day I played around alot with flourescent lights and dimmers, the two do not play nicely together for long!!!!

[NickJacques]

Remember also that followspots require some time to "warm up". If you just turn them on from the dimmer, you'll have very poor light from the followspot until the bulb warms up and becomes brighter.

I would recommend just using the dowser on the followspot. It takes some training, but doing it that way is better than having something look like crap.

Just my 2¢.

[jbeutt]

First off, he said he doesn't need to dim them, he's only using the dimmer as a means of switching them off at the same time. That should work alright with the ballast, as at 100%, the lights are getting a full 60hz signal.

Why not just call the cue and have the ops practice enough to turn them off together?

I guess I get what you're saying about the ballast if it were dimming. However, he could always use a sine-wave dimmer and that should work.

Also, I'm pretty sure his fixture doesn't use a ballast, which makes the whole thing pretty moot.

[ship]

The FLE comet lamp is a halogen MR-16 lamp which is 360w/82v. Dimming/setting them to go or not go in power won't be a problem.

Only problem should be in if there is a cooling fan, dimming them could cause problems to that fan, and killing the power to the lamp cold kill the power to the fan which even if halogen could have dire effects on the lamp cool down rate.

Be cautious of that cooling fan, otherwise the lamp if seperate should work perfectly fine if not even dimmed by a dimmer.

Beyond this however, practicing and timing of cues should solve the problem in a much more simple way.

[soundlight]

When I have this problem, I hook both of our followspots up to a power strip, and then just turn the switch on the power strip on and off. No issue of dimming. But, ship is right, there would be a problem if they had been running for a significant period of time and the cooling fan was turned off as well as the bulb. The bulb would stay hot for much longer. I didn't have this problem because when I did this, it was only for a minute or two each time that they were turned on.

[tfactech]

OK here’s my two cents…

I think the Altman Comets are similar to my Dyna spots in lacking a ballast. I use my two with the dimming system all the time. (my throw distance is only 40ft) Even though you don’t need to dim them you should rewire them with a double pole single throw switch. Then run a separate power feed for just the fan on one pole of the switch and run the lamp through the other. Remember to not use the ground on the fan, just the one on the lamp, (which gets plugged into the dimmer). This way you don’t take a chance on a ground loop. Now you can always dim the lamp and the fan will still run on full 120v and all the operator does is throw one switch. When I call “standby spot” my operators turn on the switch and then I call “go spot” and hit the cue button, lamps come on and all is right with the world. Then after the cue for "spot out", they can leave the fan on for a few minutes. Trust me, its nice to be able to dim out the spots at times. (I’ve always hated the effect of just shutting them off) Most dimmers produce some sort of “dirty voltage, even at 100%, and that will kill the fan eventually. (and those ballasts too) (I know, its minimal and you need an good oscilloscope to see it)

Of course, you could just practice to get the timing down…but I like to make things complicated…