Film-Tech Forum ARCHIVE: Seeking Information on a SanRex Rectifier

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Posted by Tom Ostertag (Member # 8318) on 01-24-2017, 02:04 AM:

Hello All,

I'm looking for any sort of documentation and/or schematics for my SanRex KCX-180H2CR rectifier. This is a thyristor rectifier, which happens to be installed in my Christie SLC-70.

The only bit of information I've found so far is that it has a similar model number to that used in the Christie SLH-D lamphouse/pedestal. The spec list for that pedestal shows:

"7kW Thyristor KCX-180CR Three Phase Input 180v/240v, 32A or 380v/440v, 16A"

The electrical ratings sound exactly like what I have, so if anyone has any information on the SLH-D rectifier, that'd probably be helpful!

I'm asking because my lamphouse has been a little noisy since I acquired it. The lamp (and not the rectifier) has always made a continuous buzzing sound when lit, and since I haven't been around other known-good systems too much, I don't really know what "normal" sounds like. The arc is stable, the light is flicker-free, and current regulation stays put where I set it.

There is a bit (less than a volt) of ripple on the DC output. The next time the lamp is struck, I can get a more precise reading of the ripple voltage.

If that's a problematic amount of ripple, I'd like to find out weather a thyristor should be suspected, or filter capacitors. This is where schematics and/or other documentation would come in handy!

Any information at all will be greatly appreciated.

Thanks!

Posted by Mark Gulbrandsen (Member # 72) on 01-25-2017, 11:46 AM:

I had a number of sites with 7KS SLC concoles running and none of them had a San-Rex rectifier in them. They all had the usual Christie boat anchor. The buzzing can be caused by lose transformer winding's on the steel transformer core. This was also very common issue with rectifiers that were produced by Christie. Some times it's possible to hammer oak wedges in between the winding and the steel core to tighten up the winding. Some times there is noting you can do about the lose winding.
Since you are probably not running a 6 or 7 kw lamp at home then replacing that rectifier with a strong compact switcher is your best bet, since Strong switchers only make noise when they blow up. (They are also repairable with some effort.) If you do look for one the grey hammertone switchers were the latest production. Note: They also run on either single phase 220 or three phase.

Mark