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#193988 - 05/03/10 11:31 PM What was this DC generator for?  
poorboy  Offline
Member
Joined: Jun 2005
Posts: 124
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

[Linked Image]

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:

[Linked Image]

Slate DC Switchboard with DC ammeter and voltmeter and rheostat knob

[Linked Image]

Rheostat and control knob

[Linked Image]

[Linked Image]

Just wondering what the load was once upon a time.


Tools for Electricians:

#193989 - 05/03/10 11:47 PM Re: What was this DC generator for? [Re: poorboy]  
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
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.


Tesla

#193991 - 05/04/10 12:18 AM Re: What was this DC generator for? [Re: Tesla]  
frenchelectrican  Offline
Member
Joined: Feb 2003
Posts: 939
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


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


#193992 - 05/04/10 12:25 AM Re: What was this DC generator for? [Re: frenchelectrican]  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,857
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).



John

#193994 - 05/04/10 01:44 AM Re: What was this DC generator for? [Re: HotLine1]  
frenchelectrican  Offline
Member
Joined: Feb 2003
Posts: 939
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


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


#193995 - 05/04/10 06:22 AM Re: What was this DC generator for? [Re: frenchelectrican]  
techie  Offline
Member
Joined: May 2005
Posts: 246
palo alto, ca usa
carbon arc projector, or DC power to the physics lab? an old elevator?


#193996 - 05/04/10 07:51 AM Re: What was this DC generator for? [Re: techie]  
Alan Belson  Offline
Member
Joined: Mar 2005
Posts: 1,803
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!


Wood work but can't!

#194007 - 05/04/10 09:13 PM Re: What was this DC generator for? [Re: Alan Belson]  
poorboy  Offline
Member
Joined: Jun 2005
Posts: 124
Central Maine
The nameplates are as follows:

DC Generator

[Linked Image]

Compensator

[Linked Image]

AC Motor (need a better pic)

[Linked Image]

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

[Linked Image]

[Linked Image]

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

[Linked Image]





#194020 - 05/05/10 04:11 AM Re: What was this DC generator for? [Re: poorboy]  
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
That's an a LOT of power for DC arc lamps...

Are better pictures on the way?


Tesla

#194022 - 05/05/10 07:39 AM Re: What was this DC generator for? [Re: Tesla]  
poorboy  Offline
Member
Joined: Jun 2005
Posts: 124
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?

[Linked Image]

[Linked Image]


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