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We have an IREM N3 Rectifier that was installed new in 1995. Besides being annoyingly loud, it has had three contactors burn out this year. Does anyone have any ideas what could be causing this? It also runs extremely hot. Is it time to replace it? We have another of the same model that was installed at the same time that is not having these problems. Any help would be much appreciated.
Thanks
Linda

Linda,

This topic would be best for film-tech.com. I have found that site to be the best for equipment problem issues.

Thanks, but will I get in trouble over there for posting on both sites? I've heard they can be really mean about that.

IREM rectifiers have adjustments to tighten up the metal laminations to reduce/eliminate hum.

I've seen some IREM's that the input terminal block connectors burn up then the contactor goes bad.

Film Tech doesn't like verbatim posts on multiple sites. Reword your request and post over there. That should cover their concerns.

The Irem rectifiers are straightforward, reliable and generally well-respected around the groups I haunt. If yours has been providing good service over the years, I'd get someone in there to give it a good going over.

From what you describe, your problem could be caused by any number of things. You'd want to start by making sure your input voltage is correct and nothing's changed there.

You say your contactor has been burning out. Do you mean the coil has burned out or have the contacts burned to the point they don't make good contact? The answer to that will send a service person in two completely different directions.

Noise and heat are also hard to pin down with an easy fix. As Ken said, loose laminations can cause a loud mechanical buzz, but that probably doesn't account for the heat.

Are you using the same size bulbs as you always have? If you've increased your bulb size, the extra workload on an undersized power supply could cause all of the problems you mention.

Past that, there's not a whole lot left. A rectifier that old probably should have had at least a couple of capacitor changeouts. If yours hasn't, a new set will extend the life of your bulbs. A partially shorted cap could be loading down the supply (bad).

You should check the diodes, though a problem there usually shows up by blowing the main breaker (if the diode is shorted) or a visible flicker against the projector's shutter (if the diode is open).

It is possible a transformer could have a shorted turn, which could manifest itself as you describe... but that would be unusual. If that's the problem however, you're probably ready for a new power supply because the fix for your old one would be expensive.

Good luck!
Jack

Thanks to everyone who replied. Your help got us through the last month and a half, but the noise factor is now so bad that we are replacing it. My question now is what is involved in installing it. Can a regular electrician do it or are there other things involved that would require a projection technician?
Thanks.
Linda

Kinda depends (good answer, eh?)...

If you don't replace the power supply with something very close to what you now have, the wiring could be a little different.

You have the obvious incoming power connections. That part an electrician should understand fine. Past that though, I think I'd want someone who knows projection equipment to at least be on hand to watch over things.

Depending on what power supply you get, your control lines could be a simple dry contacts, or they might need to have power on them. You need to make sure the bulb cables are polarized right, and that the current setting for the bulb is correct. Some supplies provide power for fans inside the lamphouse... others don't. Interlock connections (the part that shuts things down if a fan isn't working or if you open a door) aren't all the same, either.

An electrician who's on the ball might understand it all, though I don't know any in my area who would take it on. Do you know enough about this to be able to tell?

If you do try it, make sure you have all the books and wiring schematics for your lamphouse, the power supply and any automation box you might be using.

I was afraid of that. My electrician is really good, but he knows nothing about projectors and such as that. Anyone know of a good technician in the midwest? Thanks Jack. I appreciate your help.

We got our new rectifier installed yesterday morning and scary though it may be....everything went without a hitch. (Scary because nothing is ever that easy around this place, so I'm waiting for the other shoe to drop) My electician is a wonderkin.... He was also here all afternoon Friday, replacing diodes on anoher rectifier. (Took us awhile to figure out what the problem was) And he works for free movies and popcorn. Anyway, so far so good until next time.
By the way, the almost silence is wonderful, worth every penny.
[This message has been edited by Linda (edited December 02, 2007).]

[This message has been edited by Linda (edited December 02, 2007).]

Glad to hear it went so well for you, Linda. If your electrician is replacing diodes, hang on to that guy!