replacement dimmer

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I'm working on some lighting at a church. The lighting is controlled by autotransformer type dimmers and one of them has stopped working (there is no output). I'm assuming that a fuse is blown but I only briefly looked at it. I do remember it being loaded to max. I've never worked on these so I have two questions: 1)any other ideas for the cause 2)what's a good replacement dimmer (affordable). I know you need more info, I'll post later.
 
Hello there. I have had some experience with that type of dimmer, and before you go thru the expense of replacing it, there are a few things to look at:

1: Check all wiring and terminations, especially at the dimmer. These types of dimmer can run quite hot, and it may be as simple as a burned or loose connection.

2: These dimmers have a movable contact or brush if you will, it can usually be replaced without too much trouble. Get the brand and model and serial numbers off of it and you can usually find replacement contact brushes.

But be aware that it is possible that if the brush was wearing out, it could have arced up the windings were it makes contact. If that is the case the dimmer is not repairable. A new brush would simply continue to arc as it hits the bad spots.

It is remotely possible that it has completely burned up, in that case replacement is the only option.

Economical replacements..depends on the total load connected but a dimmer of suitable grade for commercial use will not be cheap.

Please post back with all the info on the dimmer and total connected load, get pics of it if possible..I may be able to steer you to a suitable replacement.
 
And a quickie warning - autotransformer dimmers are nice in that they dont generate dimmer hash, but a replacement SCR dimmer will, and what happens next depends on if the church has a sound system, and if it has, how resistant said system is to dimmer hash. If the sound system suddenly starts buzzing it'll be declared to be your fault. The annoying thing is that it isn't; it's the sound system's responsibility to reject the noise, but it doesn't mean the customer will see it that way...
 
Thank you guys for your replies. It won't surprise me, mxslick, if it is a problem due to arcing/worn brushes, the equipment is over 30 years old and I don't think it has been maintained. I will take some pictures on my next trip. Last trip I was in a rush, but I did measure around 16 amps on that circuit. The dimmer rating was about 16 amps as well. The connections at the J-box were fine. The brand was something like luxtron. I know that's not correct but it's been a couple of weeks, can't remember.
 
Yeah, dbuckley, I know these dimmers are kind to the sound system. Although one of them is a little squeaky when operating. I definitely don't want to ruin the next church service. If I have to, I'll just install a contactor and eliminate the dimmer. I can use all the advice I can get on finding a replacement or parts. You obviously see my concern not to affect sound. Oh yeah, I have two existing #12 control wires that run from the sound booth to an electrical room where dimmers are located. If you guys could check back in the next couple of days I'll have more info. Next time I'll wait to post, but at least you got me pointed in the right direction. Thanks.
 
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