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Topic: Rotary phase Converters

Jim Spohn
Film Handler

Posts: 95
From: Bakersfield, CA, USA
Registered: Jan 2003

posted 09-19-2003 09:44 AM

Erick..Jack and Gregg are right on the money. I run my entire theatre (air conditioning, pipe organ and booth)from a home made three-phase rotary converter. It is as simple as you could imagine, and completely automatic. There are alot of wive's tales about these units from people who know nothing about them, but the real truth is that the three phase output is stable and at precise frequency. All my motors run from one unit. A converter using a 5H.P. Motor will drive FOUR units with 5 H.P. motors on them OR any combination or number of motors not to exceed a total of twenty horsepower (from a unit using a 5 H.P. motor). The unit is simply a three-phase motor with a capictator, timer and contacter. The cap and timer start the three-phase motor turning then drop off line and the motor (any size)will continue to turn acting as a rotary transformer. Motors connected to this unit will start and run just as if they were connected to the three-phase utility. The converter motor just sits and spins. I have built dozens of these units and they work fine. Email me off-line and I'll send you a schematic. Jim

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Pete Lawrence
Expert Film Handler

Posts: 192
From: Middleburg, PA
Registered: Aug 1999

posted 09-19-2003 09:48 AM

quote:
I will be doing mobile projection and as you know, 3 phase power just isn't available everywhere.

Neither is 220 volts of sufficient amperage if your planning on 4k lamps. Have you given any consideration to a crystal sync AC generator? Might be a little pricy, but that would make you totally self supported and you could set up anywhere.

Here is a nicely done home-made converter using a three phase motor. http://www.metalwebnews.com/howto/phase-converter/3-phase.pdf

Here are a couple commercial versions with prices. http://www.mscdirect.com/PDF.process?pdf=1421&Section_Id=1117&Keyword=Y

[ 09-19-2003, 11:15 AM: Message edited by: Pete Lawrence ]

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Jack Ondracek
Film God

Posts: 2348
From: Port Orchard, WA, USA
Registered: Oct 2002

posted 09-19-2003 08:37 PM

My rotary converter was made by Steelman Industries of Kilgore, TX. I bought it back in 1982... still works great!

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Erick Akers
Arse Kicker

Posts: 201
From: Dallas, TX, USA
Registered: May 2001

posted 09-24-2003 06:14 PM

Thanks Jim,
That confirms some of what i have been told.
Sent you an e mail, please get back with me.

Also, Is there anything else to share with us on this subject?

[ 09-26-2003, 12:10 AM: Message edited by: Erick Akers ]

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Daryl C. W. O'Shea
Film God

Posts: 3977
From: Midland Ontario Canada (where Panavision & IMAX lenses come from)
Registered: Jun 2002

posted 07-01-2004 12:42 AM

While realizing that running a rectifier off of a rotary converter or phase drive is really inefficient, can anyone recommend a variable phase drive, that they like, that I could use with an Allanson 2K rectifier (220V @ 20 amps I believe). Of course, phase drives are quite common... just looking to see if anyone has a favourite.

Alternatively, a significantly less expensive (solution), equipment wise, single phase 2K rectifier that provides for lamp life in-line with the Allanson.

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Robert DeLoss Marken
Film Handler

Posts: 11
From: stockbridge, ga, usa
Registered: May 2004

posted 07-01-2004 05:09 PM

Erick,
Hi! 3 phase is not a big deal unless it is for some huge industrial application. Any 3 phase device will operate on single phase without damage but at reduced efficiency. For a motor it will rotate at the same RPM but at 2/3 of the HP. If 3 phase is needed then a home made phase converter is easy to build. Go to a junkyard and get a 3 phase motor out of some worn out appliance. This motor can be worn out because it is used to supply the third leg and only runs, does not power anything. It must be as large or larger than the working motor. (5 bucks max) It does not have to match the working motor in star or delta. You can get exotic and build a starting system out of capacitors, or do as Greg Mueller does, and start it manually. I can send you lots of info on how to build and wire a converter, but that info is available on the Internet. Just surf phase converters and you will find probably 1K plans and etc.

If your need is an electronic device you can easily convert that device to single phase. I converted a pair of 3 phase tungar bulb rectifiers that power my carbon Enarcs to single phase. You just have to move some transformer wires around. And you can get solid state diodes to replace the tungar bulbs if you desire.

In summery: 3 phase is not a BFD and in most cases is not necessary.

Bob Marken

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