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#213040 03/12/14 12:25 AM
Joined: Mar 2004
Posts: 251
One of my customers is cleaning their warehouse. They have a mint condition Allis-Chalmers 79.5 KVA dry transformer 450-480 Pri. 120-208 Y Sec. Since A-C went out of business in the early 1990, this must be 30-50 years old. Anyone know when they made dry transformers. Hate to see it go in the scrap pile but too big for me to store.

WESTUPLACE #213041 03/12/14 04:39 AM
Joined: Jun 2004
Posts: 1,273
My MGM dry-type transformers have their manufacturing date stenciled into the name plate.

BTW, there is a steady business by those purchasing just such units.

Salinger is always in the market.

I'm constantly getting solicitations in the mail for such gear.

When you say MINT CONDITION I take that to mean that it's never been installed.

In such a case, it would be deemed New Old Stock -- and could be sold on eBay PDQ.

You'd need to get much more specific since no-one makes 79.5 kVA transformers. NEMA has set sizes -- which just so happen to be detailed in Ugly's tables.

The nearest (NEMA) size would be 75 kVA.

It's also essential that you specify whether it's 3-phase DELTA or STAR on the primary side... and DELTA or STAR on the secondary side.

By far the most common transform is Delta to Star: 480 to 208Y120.

Other essential metrics: its temperature rating, its weather rating 1, 2, 3R, etc.

Also the taps on the primary and secondary. These are normally listed right on the name plate as plus/minus voltages.

It's also essential to know whether it's copper or aluminum. It's Z, or impedance is also important.

If the unit has been in service its value plunges -- as the bidding assumption is that it's a cripple/ or in some way uneconomic.

Good luck.

WESTUPLACE #213042 03/12/14 09:37 AM
Joined: Apr 2002
Posts: 7,350
Likes: 7
There is a trade paper 'Electrical-Advertiser' that has numerous dealers in all types of electrical gear. You may even locate someone close to you.

As Tesla stated, all the info will be required, "new/unused" will make it easier to sell.

WESTUPLACE #213043 03/12/14 11:27 AM
Joined: Jul 2001
Posts: 599
JBD Offline
450-480V primary

These are not standard general purpose transformer ratings. Was this a spare transformer for a special purpose?

WESTUPLACE #213044 03/12/14 04:04 PM
Joined: Apr 2002
Posts: 7,350
Likes: 7
Roughly 5.5% higher then a 'standard' 75KVA, with a primary voltage range of 450-480 volts. Yes, that is kind of 'odd'.

If I needed a 75, and this one was 'mint' and meets Teslas data, I would have no issue with it.

WESTUPLACE #213045 03/12/14 07:09 PM
Joined: Mar 2004
Posts: 251
I am sure it said 79.5 ( I agree its not a standard value) I will try to photograph the nameplate Friday when I return. It has been installed. Clarify mint or maybe real good, no rust, good paint, little scratches or dents. Has a pigtail (Greenfield) hanging on it. It does have impedance on the nameplate. I assume copper, but will also check that. The primary has multiple taps (fixed Sec) The owner was not sure of its history, but the location of much of the other equipment (Printing) in the lot came out of a bldg that was formally a Home Depot. (One of the first in Houston) That was later a printing (Screen) plant.

WESTUPLACE #213046 03/12/14 10:44 PM
Joined: Apr 2002
Posts: 7,350
Likes: 7
IMHO, being 'used' will effect the value a lot for a reseller. KOs indicate 'used' a pigtail shout it.

'Used' and 'old' will really hurt.

I had a 300KVA, 4160 to 120/208, delta/y, dry, Challenger that was new, installed for 9 days, taken out of service, and it sat at my shop for 5 years! I still had the factory paperwork, bill of laden, etc. Could not get a dime for it.

It was Al windings, so the scrap value was squat; I wound up putting it in a dumpsterwhen I moved and started to close shop.


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