Control/Dimming Sensor rack maintenance

Thetechmanmac

Active Member
Joined
Sep 1, 2015
Location
Northeastern NC
My theatre has 2 ETC sensor racks that need some love. The school has been open for 11 years, and as far as I know the dimmers have never been cleaned, or (much to my dismay) ever been shut down (fans and all). In the dimmer room, feeding said dimmers is a 600 amp switch. Install type. (not quite sure what else to call it, so please enlighten me on what the correct terminology is. I don't think it is a company switch though. Definitely not ETC made).

So to shut down the dimmers and do some much needed cleaning, are there any steps I need to take to shut down or, or just "throw the switch"?

Also, any particular things I should be on the lookout for while i'm in cleaning?
 
Last edited:

MNicolai

Well-Known Member
Premium Member
Fight Leukemia
Joined
Mar 30, 2008
Location
Sarasota, FL
If you're a student at a college, I strongly advise you to first seek out the approval of a faculty member before diving into the rack. If you're a student at a K12 school, it's probably best you don't go digging into the racks but you could try and borrow some time from the school's maintenance electrician and look at the dimmer racks together. If you're a faculty member, do what you want (safely, that is...)

ETC has a helpful guide for how to clean your racks and modules safely.

Don't kill the 600A disconnect unless/until you're certain you know what's connected to it. In an ideal word, it is in fact the dimmer racks. In a non-ideal world, it's the other 600A disconnect in the room that feeds the dimmer racks and the one you just killed was actually for the building power. Verify as best you can what you're killing power to before you flip any disconnect switches.

If you power down the racks, make sure you aren't killing lights to occupied areas of the building. If you have an ELTS transfer switch to power emergency lighting, you should manually trigger that to turn on some stumble lights throughout your venue while you work on the racks.

Major things to consider when checking out a dimmer rack:
  • Are the filters clean?
  • Are the vents into the dimmer modules clean?
  • Are the fans working?
  • Are you sure all the fans are working?
  • Is there a big fat layer of dust or debris in the room that'll provide a steady source of grief no matter how well you clean the rack?
 

Thetechmanmac

Active Member
Joined
Sep 1, 2015
Location
Northeastern NC
Thanks for your response! I am a high school student, but am pretty comfortable calling myself a TD. (I probably spend more time in our auditorium than most and am there for 99% of all outside or school-related rentals/shows) I will have our auditorium supervisor there with me when I do this. Im pretty sure the disconnect is only for the dimmers. Looking at some pictures I took a while back of the room, it says "dimmer" on the switch. We do have an ETLS, but I will be powering down when the auditorium is unoccupied. I will probably save testing that system for another day. Who knows what what other emergency systems it is linked with.
 
  • Like
Reactions: Patch29

josh88

Remarkably Tired.
Premium Member
Fight Leukemia
Joined
Jan 26, 2010
Location
Ypsilanti, Michigan
Thanks for your response! I am a high school student, but am pretty comfortable calling myself a TD. (I probably spend more time in our auditorium than most and am there for 99% of all outside or school-related rentals/shows) I will have our auditorium supervisor there with me when I do this.
What you've said is good. I will add though, it doesn't ,matter what you call yourself. It matters what the school calls you which is most likely a student and potential for liability. Snap judgement, it sounds like you're smart and having the supervisor is good and will cover you for a lot. But remember that from an authority and liability standpoint you're viewed as a nobody. I don't mean to offend but it's just reality. So having your teacher/supervisor supporting you and there with you. Be aware of that, don't think too highly of yourself and keep doing what you're doing, students with good attitudes who are proactive and want to help tackle maintenance and upkeep are appreciated by those supervisors and TDs who could use a hand.

/rant



Sent from my iPad using Tapatalk
 

MNicolai

Well-Known Member
Premium Member
Fight Leukemia
Joined
Mar 30, 2008
Location
Sarasota, FL
I am a high school student, but am pretty comfortable calling myself a TD.
While your initiative is admirable, titles are like national borders. Just because you stake your flag in the ground doesn't meant jack unless everyone around you agrees to recognize those new borders of yours. Probably fine if your auditorium supervisor is on board, but as a general rule don't think calling yourself something makes it so. It's a an easy way to get yourself blind-sided by a mess you never anticipated and get burned in a way that stings for years.
 

tjrobb

Well-Known Member
Joined
May 14, 2009
Location
Cedar Rapids, Iowa
One thing to remember - stand to the side and sideways to the rack when you repower the racks. If, God forbid, there's a fault it'll help save your face and possibly your arm. Also, DO NOT power on unless the rack breakers are off, see reason above.
 

JD

Well-Known Member
Joined
Jan 1, 2005
Location
North Wales PA
Chances are the rack has been powered down and back up many times over that 11 years simply due to power outages. We have no control over those, but we do on planned power-downs, so all of the above does apply. Even flipping a 600 amp breaker caries it's own risks especially if the rack has been apart. Arc Flash is one horrendous thing, and although breakers have a lot of safeties built in, they themselves can explosively fail.
 

Fountain Of Euph

Active Member
Joined
Dec 16, 2013
Location
Illinois
ALWAYS have two people working on dimmers. I did my sensor rack last year, and me and a maintenance guy/tech did it together. As a student worker, I must be supervised when im in the dimmer room. It doesn't matter that i know more or that I have the title of lights tech. Im otta there in 4 years, and the rack will probably never graduate...

Its a safety thing too. Most dimmer rooms are out of the way places, where they will never hear you scream.* Its best to have someone else there incase somthing goes wrong.

If your all the way off, vacuum everything!
You can also wash the front pannel screens, as long as you put them away dry.

*except at my high school. It was in the makeup/mens dressing room... that made for some interesting stories...


Sent from Taptalk for Android, this was.
 

Thetechmanmac

Active Member
Joined
Sep 1, 2015
Location
Northeastern NC
I am planning on doing this next week with some other faculty members. They are located in a closet off of a main hallway...but, also in the closet is a bunch of crap. (its the PTO storage room). Theres fake plants, signs, many things that are flammable. Im surprised the fire marshall hasn't gotten them for it.

But anyway, thanks everyone for responses and advice! Now I know some of the things to be aware of!
 

MNicolai

Well-Known Member
Premium Member
Fight Leukemia
Joined
Mar 30, 2008
Location
Sarasota, FL
Couple tips for working inside racks/panelboards/electronics/such-not.

If you have modules removed, a good practice to get in the habit of is sticking one had in your back pocket and working inside the rack with your other. Not always possible depending on what you're doing, but it's an old electrician's trick for making sure that of all of the things that could still happen, you won't find yourself with 208V being driven straight across your heart into one hand and out of the other.

We have a saying, "Trust, but verify". Just because you've thrown the breaker don't assume something has been powered down completely or that there isn't some other auxiliary power feed into some components you may come in contact with. Double check for voltage between conductors or buss bars with a voltmeter or a known-working volt-tick. Preferably a voltmeter.

Also be wary of setting tools down inside a rack. Dimmer rack incidents tend to few and far between, but the one's I've heard about have involved screwdrivers or some other conductive tool forgotten inside of the rack when it was put back together.

When I'm dusting out electronics I like to have a can of compressed air on-hand for anything that a vacuum isn't aggressive enough so. I also keep a few sizes of stencil paint brushes with me for dusting in between components, fan blades, or heat sink fins.
 

MK 17

New Member
Joined
Dec 20, 2016
Location
Chicago
Hi All,

We have 3 sensor racks that have gotten quite dusty. We're planning on cleaning them out later this week, but before we do, I'm wondering what the best way to go about cleaning the rack/dimmer cards is. I was going to use an air compressor but will moisture be an issue? ETCs website seems to recommend canned air, but that's quite a bit of canned air... We also have a brand new shop vac if that could be an option.
 

JD

Well-Known Member
Joined
Jan 1, 2005
Location
North Wales PA
It doesn't hurt to use the shop-vac to suck at all the air intakes. This reverse flow will dislodge all the heavy dirt. Once that is done, an air compressor works very nicely. unless your compressor tank is so full of water, that it is actively spitting it out, you should not have a problem. If your compressor is fitted with an "oilier" for air tools, you want to remove that as you don't want to be spraying anything flammable in there.
I am actually not fond of the "canned air" approach, as many of those products do NOT contain air! In fact, since the ban on CFC's, I have actually seen these contain propane and other flammable propellants! For obvious reasons I would not use those!
 
  • Like
Reactions: RonHebbard

JJBerman

Active Member
Joined
Jul 10, 2014
Location
Middleton, Wisconsin
Unless the dimmer modules are extremely dusty, all you need to do is vacuum them in place. If you do feel it necessary to pull them out, vacuuming may get all the dust.

Follow the documents instructions on cleaning the control module as that has some sensitive electronics on it.

Make sure the doors to your racks has a filter(s) on it and clean that. That filter is the first line of defense against dust and with regular cleaning, you will nearly never have to clean the dimmer/control modules as the filter will get everything.

If/when using compressed/canned air, try to have some space between you and the rack to prevent any dust from flying into the rack.
 
  • Like
Reactions: Fission

RonHebbard

Well-Known Member
Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
My theatre has 2 ETC sensor racks that need some love. The school has been open for 11 years, and as far as I know the dimmers have never been cleaned, or (much to my dismay) ever been shut down (fans and all). In the dimmer room, feeding said dimmers is a 600 amp switch. Install type. (not quite sure what else to call it, so please enlighten me on what the correct terminology is. I don't think it is a company switch though. Definitely not ETC made).

So to shut down the dimmers and do some much needed cleaning, are there any steps I need to take to shut down or, or just "throw the switch"?

Also, any particular things I should be on the lookout for while i'm in cleaning?
Addressing ONLY what to call your 600 Amp switch. (Regardless of what it's feeding.) It could be a "fused disconnect", a circuit breaker, a non-fused disconnect, an isolation switch or any of several other possibilities. The term "Company Switch" is normally reserved for switches intended to supply power to portable equipment normally associated with travelling / touring productions or "companies". Please forgive my oversimplification.
Toodleoo!
Ron Hebbard
 

Users who are viewing this thread