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Author Topic: who uses motor-generators?
Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 05-09-2003 10:06 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
The "haunted theatres" thread in yak that led to the discussion of theatre basements has led me to ask this: who is still using motor-generator sets instead of rectifiers? For those who are: why? Is there any advantage?

The theatres that I know of which are still burning carbon haven't run generators in years.

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Gordon McLeod
Film God

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From: Toronto Ontario Canada
Registered: Jun 99


 - posted 05-09-2003 10:48 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
The big hertner transvetters typically provided better DC than most rectifiers did
In fact I have had xenons on them that never go black

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Chris Markiewicz
Expert Film Handler

Posts: 209
From: Glenaviegh, County Tipperary, Ireland
Registered: Aug 2002


 - posted 05-09-2003 11:55 PM      Profile for Chris Markiewicz   Email Chris Markiewicz   Send New Private Message       Edit/Delete Post 
The Palace in Hilo, Hawaii is still using motor-generators to run their Ashcraft Suprexes and E-7s.

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Mike Blakesley
Film God

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From: Forsyth, Montana
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 - posted 05-10-2003 12:26 AM      Profile for Mike Blakesley   Author's Homepage   Email Mike Blakesley   Send New Private Message       Edit/Delete Post 
We used to use one that looked just like the one pictured above.

The thing sat right in front of the #1 projector and made quite a lot of noise. One of the first things done after I acquired this theatre was the automation of the booth and the dumping of that generator.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 05-10-2003 02:12 AM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Motor Generators were cool. Xenon bulbs liked them. However, the open circuit voltage was not high enough to allow the igniter to fire and the lamp had to be fired manually. At the Lido Theatre in Mount vernon, I used the MG set as a atandby in event of a rectifier failure.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
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 - posted 05-10-2003 08:08 AM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
Atlantic audio visual made a booster kit as did xetron and Kniesley to provide a higher open circuit voltage

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Bernard Tonks
Jedi Master Film Handler

Posts: 619
From: Cranleigh, Surrey, England
Registered: Apr 2001


 - posted 05-10-2003 09:05 AM      Profile for Bernard Tonks   Email Bernard Tonks   Send New Private Message       Edit/Delete Post 
I was fortunate to work in two cinemas with Motor Generators. Both had two generators, one being a standby alternating weekly. The DC was so pure and smooth that once you set the carbon trim they never need touching throughout a reel. The generators at the Regal, Kingston-upon-Thames, a 2500 seats cine-variety theatre was later sold to Thames Television.

There were also quite a few Diesel Engine driven generators, but most later converted to Electric Traction.

The picture shows one of the Motor Generators at the Carlton Theatre, London. You can judge the size of these monsters by the door on the right. The 2nd picture is of myself beside No 3 projector 35 years ago in 1968. [Big Grin]
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Michael Harlow
Expert Film Handler

Posts: 170
From: Faversham, Kent, UK
Registered: Jul 2002


 - posted 05-10-2003 09:11 AM      Profile for Michael Harlow   Email Michael Harlow   Send New Private Message       Edit/Delete Post 
We had a motor generator here in Faversham which was used for the secondary (emergency) lighting. The odd thing was, that it was a DC motor driving a DC generator. Of course there was a rectifier to convert the AC to DC to drive this thing. We found that it was around 50yrs old and although still going strong, it was using some 2kw of electricity and hour, it had to go. We have new rectifiers now and use around 300w per hour. They paid for themselves within a year! The Generator was a Brown Bouvier? and the rectifier was a Westinghouse.

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Robert Throop
Master Film Handler

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From: Vernon, NY USA
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 - posted 05-10-2003 09:13 AM      Profile for Robert Throop   Email Robert Throop   Send New Private Message       Edit/Delete Post 
We still use a generator at the Stanley in Utica. It's a Westinghouse 250 amp 100 volt job installed when the theatre opened in 1928. You can still balance a coffee cup on it while it's running with no danger of a spill. The Landmark (formerly Loew's State) in Syracuse also uses a generator.

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Stephen Furley
Film God

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From: Coulsdon, Croydon, England
Registered: May 2002


 - posted 05-10-2003 04:47 PM      Profile for Stephen Furley   Email Stephen Furley   Send New Private Message       Edit/Delete Post 
Some photographs from the Loew's Jersey last year, I hope they don't mind me posting them.

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These are the long-disused motor-generator sets, installed in 1929, I would guess that they were used until the early '50s, when the Ashcraft equipment was installed, but there is very little wear on the commutators. Note the open frame of the generators, it would be quite possible to put your arm into the frame while they were running! They are bigger than they look, I think about the same size as the one in Bernards picture. I was quite surprised by the size when I saw them again a couple of weeks ago, I had forgotten how big they were. Restoration and refurbishment work is still taking place, hence the paint!

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This is one of the three Ashcraft selenium rectifiers which replaced them. They are installed in the original generator room, the block of concrete on the left is the plinth that the generators are mounted on.

Interestingly, the generator/rectifier room, rewind room, and various other rooms lead directly off the projection box, there is no connecting corridor between them, and the whole lot is reached by a few stairs through a door at the back of the auditorium, the regulations here would not have allowed that in nitrate days. Also, thee is no means to drop the fire shutters from the auditorium; in a British theatre there would have been a small red box on the back wall of the balcony with a wire handle inside for this purpose. These were sometimes mis-used during Saturday morning childrens shows! Even the College where I work had this, despite having been built after nitrate finished, and only ever having 16mm installed. I managed to acquire the b&H 609 carbon arc machines when they were thrown out.

In the rewind room there is a massive film storage cabinet, standing about as tall as me, built in to the room, and vented to the outside, I have never seen anything like that here.

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This is one of the Ashcraft Super Core-lite lamps which the rectifiers are supplying, mounted on a FP20. The tall object standing behind the projector is an Ashcraft water cooler.

One last picture

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This one shows the Brenographs, note the unusal venting system, rigid ducting, rather than a hood.

Bernard, I wouldn't have recognised you from that photograph!

Many early cinemas used Crossley gas engines, made in Manchester, before mains electricity was available. There is one in the small cinema which has been re-built an the Black Country Museum, in Dudley. The autitorium was gas lit, the house light dimmer being a log rod running the length of the building, just under the roof! I don't know if the projection room was gas lit, presumably the cinematograph act would have put a stop to that, after 1910.

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Bernard Tonks
Jedi Master Film Handler

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From: Cranleigh, Surrey, England
Registered: Apr 2001


 - posted 05-10-2003 07:02 PM      Profile for Bernard Tonks   Email Bernard Tonks   Send New Private Message       Edit/Delete Post 
Interesting pictures Stephen. The commentators at the Carlton were is almost perfect shape after 41 years since opening in 1927, they really were cared for. I had the luxury of two house engineers who looked after them, as they did with everything else including the screen masking and two sets of curtains. I was only responsible for the projection room. The massive 50-foot deep stage with fly tower was in use for one year only; Paramount Pictures took over the Carlton for cinema only use in 1928. Although no longer used, the stage lighting board had salt water dimmers that still worked, I was shown the batten lighting behind the screen.

Re: Loew’s Jersey Theatre, Never seen two Brenographs in a projection box before, are they in working order? Must go there one day, I visited New York nearly three years ago. Would be great if the Brenograph at the disused State Theatre, Grays could be installed at the Odeon, Leicester Square replacing the old Ross Scenograph.

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Stephen Furley
Film God

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From: Coulsdon, Croydon, England
Registered: May 2002


 - posted 05-11-2003 06:41 AM      Profile for Stephen Furley   Email Stephen Furley   Send New Private Message       Edit/Delete Post 
Bernard wrote:

quote:

Re: Loew’s Jersey Theatre, Never seen two Brenographs in a projection box before, are they in working order? Must go there one day, I visited New York nearly three years ago. Would be great if the Brenograph at the disused State Theatre, Grays could be installed at the Odeon, Leicester Square replacing the old Ross Scenograph.

Two Brenographs not common; I never saw either place, but I'm told that the Gaumont State, Kilburn had two, and the Gaumont Palace, Lewisham may have done, conflicting reports on that one. The 1929 Brenkert catalogue, available to download from the Film-Tech manuals section, does specify a minimum spacing when two are installed.

The ones at the Loew's are a long way from being usable, I doubt if they have seen use in the last fifty years, but there's nothing that would be impossible, or even very difficult, to put right, given time. The small band of people working on the theatre have achieved much, but there is still a lot of work to be done, so it won't happen overnight.

Basically, the problems are:

The machines are rusty, but it's only surface rust, and would clean up.

Most mechanical parts are seized solid, and will not move, they would need completely stripping down and cleaning.

All sixteen lenses are missing, but most of the retaining clips that held them are still there. I don't think new lenses would be too much of a problem, the people who supply school science labs might have something, even if it meant turning up adapters for slightly smaller lenses, or something.

Some of the condenser lenses are missing, but there are enough to get one machine working.

A few of the twelve mirrors are missing, on all the others the surface has gone, not a major problem to replace.

One section of extraction duct is missing, but could be made. If you lok at the ducting just over the front of the top lantern on the far machine, you can just see a place where one section slides inside another, to allow the lanterns to move.

The large D.C switches have been removed from their housings, but these things can be found.

It's really a question of labour, if I lived a bit nearer, I think I could get one of them working, without too much difficulty, and could probably afford the parts, but I can't exactly nip over there for a few hours in the evenings.

The place is only a few minutes from the centre of New York, the Path trains from Manhattan serve Journal Square station, which is just across the street.

As built, the place was something over 3000 seats, the auditorium is probably about the same size as a British 2500 seater, but the balcony is much bigger, maybe seating an extra ten rows, or so, compared to a typical theatre.

Working Brenographs difficult to find anywhare, the Byrd, Richmond VA has one, still in regular use, recently converted to tungsten lighting, this was the last working one that I knew of still burning carbons. The Enigma, Bletchley Park had one installed recently, it is in good condition, and has many of the accessories, but is a xenon conversion, using vertical lamps in the original lanterns, so it looks original.

The one at Grays was in working order, but the motorised feed had been removed, this was quite common, the worm driven gears had a habit of stripping, and no spares have been available for a long time.

It's a pity that Grays closed, I went there to a few concerts, in the days when the auditorium basically served as a fire escape from the club which used the foyer area. Most original equipment was still there, one projector had been removed, but I understand was still stored somewhere in the building, two of the remaining three had been converted to xenon, but the lamps were far too small for a screen that size, only 2.5k, they really needed at least 4k, I never saw the remaining carbon machine running, so I don't know how that compared. The spool boxes had been removed, but could have been replaced.

Original rectifier plant, mercury I think, was still installed, and usable, but small modern rectifiers in the projection box were normally used. The organ was in pretty good condition, including the piano, and an extra stop was installed not long before final closure, there were a few problems with the Mellotone unit.

There were proposals for use as a church, but these were turned down. The place was listed, but there were problems with water where it shouldn't have been, The club closed, the owners of the building wanted to sell it, I don't know what it's final fate was.

Does the Odeon ever use that Ross device? I visited the box many years ago, the Victoria Xs were still there, but after they had been converted, and I don't remember seeing the thing, but it must have been there. I know that it was converted to xenon at some time. How does it differ from the Brenograph? I've only ever heard of a couple of places that had them.

To return to the Loew's for a moment; anyone who doesn't already know care to guess what the left hand object in this picture in the rewind room is? I've never seen one before.

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When I first saw it I thought it might be for storing lantern slides, but that's not it.

Scroll down a few lines to the next picture for a clue.

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John Anastasio
Master Film Handler

Posts: 325
From: Trenton, NJ, USA
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 - posted 05-11-2003 07:32 AM      Profile for John Anastasio   Author's Homepage   Email John Anastasio   Send New Private Message       Edit/Delete Post 
Great observations on those Brenographs, Steven. I've often been up in that booth with the machines and you're right about getting them rebuilt. It would be a real labor of love for someone with a lot of patience and access to a metal shop. Running them must have required two projectionists with a flair for showmanship. I'm sure that Mitch, Steve and Bernie could handle it, though.

The cabinet is for storing Vitaphone discs. The Simplex standard with the turntable for them that you've shown is a working machine, although I don't think I'd want to play any discs with that pickup. The tracking pressure on the stylus is pretty high. Most of that stuff has been beautifully restored by Bob Eberenz, the theater's chief technical engineer, who's done an amazing job. The booth has two Simplexes, a pair of Kinotons, a 16mm machine (a Bauer, I think) and two Brenographs. It's pretty impressive.

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Bernard Tonks
Jedi Master Film Handler

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From: Cranleigh, Surrey, England
Registered: Apr 2001


 - posted 05-11-2003 10:13 AM      Profile for Bernard Tonks   Email Bernard Tonks   Send New Private Message       Edit/Delete Post 
Come to think of it Stephen, I’m sure you are right in saying that the Gaumont State, Kilburn had two Brenographs. You’ve jogged my memory, I went up into that projection box around 1965. A friend of mine was also the chief projectionist there.

Not sure if the Odeon ever use the Ross device, or remember how it differs from the Brenograph. Last time I saw it was over three years ago, and there was a large plate glass effects disc broken. [Frown]

The Projected Picture Trust did a sound-on-disc full feature showing at Muswell Hill a few years ago.

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Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999


 - posted 05-11-2003 10:42 AM      Profile for Frank Angel   Author's Homepage   Email Frank Angel   Send New Private Message       Edit/Delete Post 
Great pics guys, thanks. The dual Brenographs must have been a Loew's thing. There was the same setup in the Loew's Kings in Brooklyn. They looked like they were in about the same rusted shape.

They were still using monster generators at the Loews right up until they closed; they were located in an adjacent room and weren't as noisy as they looked like they would be. There is also evidence that before the generators, they were using DC that was supplied directly from Con Ed. There is a big DC panel in the booth that is wired directly to outlets in front of the projectors and followspot. How cool is that? No worry about rectifiers or generators, just plug into a socket and you've got DC with as much current as you could possibly want. I worked a theatre years ago (when I looked even younger than Bernard's pic) and I agree, those arcs driven by generators, once adjusted correctly, didn't budge. You could go an entire show without having to make even the slightest adjustments. I can't say that about our solid state rectifiers today, but then again, today Con Ed sends voltages that vary from 110v to as high as 130v on a daily basis. If you are running a show across the 5pm to 6pm hour, you'd better watch those arc gaps. The Knisley rectifiers don't have voltage control that can deal with that kind of swing without it showing up in the DC output. I've had to buy voltage regulators for my sound racks because at 130v, you can expect lots of equipment to meet their early demise.

Also in this Loews three projector booth was a rack with Perspecta Sound equipment, something that seems to have been commonly found at the larger Loews theatres.

I don't know the manufacturer of the arc followspot that we found up there, but it is an amazing instrument with dozens of pulley's and controls to change the color gel boomerang and to pull multiple lenses back and forth to size the spot. It is made of brass so no rust, and the balance is so precise, that you can move the large, heavy body smoothly in all directions with one finger -- just a beautiful thing to look at and touch. And it's not DIGITAL....imagine that!!

Frank

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