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Topic: Need advice on wiring A Kneisley Lamphouse

George Snyder
Film Handler

Posts: 2
From: Gravois Mills, Mo. US
Registered: Jan 2012

posted 02-07-2012 07:53 PM

I have A Kneisley Lamphouse for A 35MM film projector which was wired up for a 3 phrase and I need to know how to hook it up for A single phrase. I know its possible because I have the wiring digrram but its not clear on the wiring of the rectifier. There is 3 black wires and 1 white leading in to the rectifier and A ground. Should I wire this as A 220 and what should I do with the third leg? Should I make A Jumper wire? Please help me. The projector and sound head works fine on 110 voltage but I need to get the bulb light working. [Confused]

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Dominic Espinosa
Phenomenal Film Handler

Posts: 1172
From: Boulder Creek, CA.
Registered: Jan 2004

posted 02-07-2012 08:16 PM

This might sound pseudo-hypocritical seeing as I don't have very much overall experience with rectifiers but I will tell you this from experience:
It's best to have an experienced technician do this. Especially if you're not an electrician/familiar with safety precautions and some basic electrical knowledge.
While relatively simple in design these power supplies can be very dangerous.

That being said, some additional information would be useful.

What power supply are you using with the lamphouse?
As far as I know the Kneisley Knitron rectifiers of which I usually see with a Kniesly lamphouse are all 3-phase. Maybe I'm wrong.

The Lamphouse itself doesn't care what the AC is, 3 or single so long as the DC it receives from the power supply is appropriate for the lamp.

On the power supply itself, which is usually a big suitcase looking thing with an exhaust fan on it somewhere should be a placque or sticker or something to go on. If not, maybe you could post a picture of it here and one of the pro's can identify it and tell you for sure if it has an option for 3-phase. Being older it likely doesn't.
The manuals for many common (and some uncommon) power supplies can be found in the warehouse section of this site and are a big help.

I was recently up against a situation with a bad rectifier that had been single phase and it was ultimately much cheaper and easier in the long run to just bite the bullet and install 3-phase to the power supply.

As for connecting it to the lamphouse, the + and - leads for the lamphouse go to the + and - outputs on the power supply.

Again, be careful, be safe, and get us that info.

Welcome to the board!

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 02-07-2012 08:20 PM

Kneisleys were just 3ph only due to the three transformers' primary windings. The description plate on top of the rectifier should be describing the incoming voltage and phase requirements.

These rectifiers stepped the voltage down before the voltage went into the diodes for DC conversion - why the tap selector on top of the case.

If you can find a STRONG switching power supply, then you can go both ways - single phase, or three phase - with these units, with no "mods" to worry about.

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Jim Henk
Master Film Handler

Posts: 364
From: San Diego, CA
Registered: Feb 2006

posted 02-08-2012 12:55 AM

The teeny one that went along with the 500w "Pup" lamphouse was originally designed single phase. Though the one I wound up with was admittedly re-wired as an accident waiting to happen. Gee, somebody forgot to include a ground wire between the rectifier and the lamphouse, apparently didn't notice the melted ammeter, and replacing the rotted insulation that made exposed copper touch the frame in lots of places, I guess just slipped their mind. Got $30 for the copper in the transformer, though, and the lamphouse proper went to a good home.

Can you say "no-phase"? I knew that you could.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

posted 02-08-2012 06:24 AM

"Most" Kneisleys are 3 phase. A few (older) ones are, in fact, single phase. Kneisleys don't "convert." One or the other. Phases are noted on the data plate, both directly and encoded in the model number. That is what we need. Louis

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Robert Minichino
Master Film Handler

Posts: 350
From: Haskell, NJ, USA
Registered: Dec 2005

posted 02-08-2012 10:11 AM

There's a fundamental difference in construction between single-phase and three-phase rectifiers. Since the three phases supplying the three-phase rectifier overlap, the ripples in the rectified DC also overlap, resulting in smoother output, therefore requiring less filtering. The single-phase rectifiers require much more filtering for a given output because the rectified DC ripple goes all the way to 0V every time the input AC switches polarity.

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