Film-Tech Forum ARCHIVE: Tapping down a Christie 6kW Rectifier

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Posted by Cameron Andrews (Member # 5246) on 11-23-2009, 10:56 AM:

I have been a follower of these forums for some time, but this is my first post.

I am trying put together a functional system from parts I have accumulated over the years. I have a 6kW Christie rectifier and an ORC 4500 Lamphouse. I run 4200 W lamps in my other ORC 4500 and would like to do the same on this one. Can the Christie rectifier be tapped down to 4200 W and hooked up to the ORC? I plan to use a century C or SA so I would like to get the most light possible without requiring a liquid cooled gate. Thanks.

Posted by Gordon McLeod (Member # 33) on 11-23-2009, 01:19 PM:

it should work
you may have to set the input to low and the output on the lowest range

Posted by Cameron Andrews (Member # 5246) on 11-23-2009, 01:48 PM:

I'm not very familiar with this rectifier and I don't have any docs on it. How do I adjust the input?

Posted by Monte L Fullmer (Member # 2797) on 11-23-2009, 06:43 PM:

(Is that for the Teton-Vu Dr.In up there in Rexburg? It's all where I started at 40yrs ago while I was going to college in that town..)

the rectifier should have three tap plates (that are bolted on the back (input) side of the rectifier-opposite side of the rotary tap switch - that goes inbetween the taps so you can either switch from high or low output amperage settings.

If you find these tap plates, you'll see three sets of studs where the tap plates are bolted to. If the three plates are tapped on the upper two studs, they are on the high side. Move them down to the lower two studs for lower output.

Still though, running a 4200w bulb from a 6k rectifier (which this figure is the maximum output anyway) you should be definitely good to go as is. ... and with that high wattage of bulb, you really should think on doing a 'water cel' with that Century being the case is cast aluminum and could warp from the immense heat that is going to come out of that ORC 4500 lamphouse-which in itself really generates the heat being a big lamphouse even with that heat filter in front of it and tonnage of exhaust,.

You have to PM me since I'm from E.Idaho ... thx-Monte

Posted by Louis Bornwasser (Member # 3063) on 11-24-2009, 03:45 PM:

You can surely get that rectifier low enought to operate the bulb. BUT can you get the no load voltage back up where it belongs.

On all smaller Christie rectifiers, it is possible to retap the boost circuit to get the appropriate no-load voltage. You will know if you have a problem if the bulb lights OK for several hundred hours, then only a new bulb will help. Louis