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#193988 - 05/03/10 08:31 PM What was this DC generator for?
poorboy Offline
Member
Registered: 06/02/05
Posts: 124
Loc: Central Maine
Custodian found out it was live when he leaned on the compensator handle while storing old electrical material from past projects and it growled. Called us to disconnect it.

Compensator



It's in a high school built in 1927, load wires are cut off, AC line is still live, (fed thru the starting compensator to the AC motor that turns the DC gen)

AC motor at left, DC generator on right:



Slate DC Switchboard with DC ammeter and voltmeter and rheostat knob



Rheostat and control knob





Just wondering what the load was once upon a time.
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#193989 - 05/03/10 08:47 PM Re: What was this DC generator for? [Re: poorboy]
Tesla Offline
Member
Registered: 06/16/04
Posts: 1273
Loc: Sacramento, CA
DC power in a 1927 school?


I'd think that it supported emergency DC power for phones, alarms, bells, lights.

Rectification, today, is effortless. Back in the day this was the time-tested solution.
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#193991 - 05/03/10 09:18 PM Re: What was this DC generator for? [Re: Tesla]
frenchelectrican Offline
Member
Registered: 02/06/03
Posts: 939
Loc: Wi/ Paris France { France for ...
I am not suprised that can be either phone or alarm or DC emergcy light circuits.

But if that was either 32V or 48V DC then it will be combation emegercy system,

Merci,Marc
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Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

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#193992 - 05/03/10 09:25 PM Re: What was this DC generator for? [Re: frenchelectrican]
HotLine1 Offline


Member
Registered: 04/03/02
Posts: 6775
Loc: Brick, NJ USA
I came upon a similar type setup many yeras ago that provided DC for a projector room in what was an 'upscale' ballroom. If memory serves me correct, the arc lamps in the old projector(s).

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#193994 - 05/03/10 10:44 PM Re: What was this DC generator for? [Re: HotLine1]
frenchelectrican Offline
Member
Registered: 02/06/03
Posts: 939
Loc: Wi/ Paris France { France for ...
Originally Posted By HotLine1
I came upon a similar type setup many yeras ago that provided DC for a projector room in what was an 'upscale' ballroom. If memory serves me correct, the arc lamps in the old projector(s).



If that is correct due the generator size is not very big so that possiblty is a correct answer.

I did look at the photo what the OP gave to us and I did notice that the motour generator actauly did rotated a little that why the custuation did hear the control lever growled.

Merci,Marc
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Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

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#193995 - 05/04/10 03:22 AM Re: What was this DC generator for? [Re: frenchelectrican]
techie Offline
Member
Registered: 05/17/05
Posts: 246
Loc: palo alto, ca usa
carbon arc projector, or DC power to the physics lab? an old elevator?
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#193996 - 05/04/10 04:51 AM Re: What was this DC generator for? [Re: techie]
Alan Belson Offline
Member
Registered: 03/23/05
Posts: 1803
Loc: Mayenne N. France
The main duty was probably charging lead acid batteries or acumulators, used in many appliances and motor vehicles. Radios back then ran with both lv and hv dc, [the latter usually suplied by zinc/carbon batteries]. As Tesla says, this was the usual way of rectifying ac in small powers before WWII, the alternative Hewlitic type mercury-vacuum arc rectifier sets cost a fortune. Hope this gets preserved!
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#194007 - 05/04/10 06:13 PM Re: What was this DC generator for? [Re: Alan Belson]
poorboy Offline
Member
Registered: 06/02/05
Posts: 124
Loc: Central Maine
The nameplates are as follows:

DC Generator



Compensator



AC Motor (need a better pic)



Here are the gauges (custodian's real motive is he said he heard you can get $150 for these on EBay)





School has a large stage and auditorium, never had an elevator until 20 years ago, and I don't know what they would have used batteries for in the school, unless it was common practice to charge a bunch and have them for backup emergency lights in case of power failure (which probably happened more in the 20's and 30's than it does now).

I heard there is an old original blueprint (the actual blue background with white lines for the drawings type of blueprint from which came the term, I assume). Maybe I can get my hands on it.

Here is the cut off load feeder, a 1" or 1 1/4" flex connector





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#194020 - 05/05/10 01:11 AM Re: What was this DC generator for? [Re: poorboy]
Tesla Offline
Member
Registered: 06/16/04
Posts: 1273
Loc: Sacramento, CA
That's an a LOT of power for DC arc lamps...

Are better pictures on the way?
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Tesla
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#194022 - 05/05/10 04:39 AM Re: What was this DC generator for? [Re: Tesla]
poorboy Offline
Member
Registered: 06/02/05
Posts: 124
Loc: Central Maine
Yes, I have quite a few projects to price out and do this summer here. I will continue to post more on this piece of equipment as I can.

This was built as a Catholic High School and now is a non-denominational private high school. It is a 3 story brown brick building which is quite a remarkable "living museum" as I see it.

The starter (compensator) has oil in the base of it...I wonder if it needs testing...what do you think?



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