Odd transformer - someone explain?

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
Found the pictured transformer, and am really puzzled by its wiring.

Could someone explain to me what's what regarding the wires, and especially the 'jumpers' at # 5/6 to 7/8?

Can't get anything out of Google for the model number...

Thanks if you can!Jumbo Transformer.jpeg
 

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
OOPS - there's a typo on the picture: The red-letter "1" and "2" are reversed. The order of the wires at the number locations does not reflect the crossover of the wires.
sorry!
 

Papabravo

Joined Feb 24, 2006
14,244
Are you sure about which is the primary and which is the secondary? Looks to me like you have it backwards.
Why do you think the wire resistance is meaningful?
 

Delta prime

Joined Nov 15, 2019
430
Hello there :)

This is the only thing I could dig up I hope it helps
APC power transformer
Class 180(H)
Item also has the following numbers :
R333H
LEI-4
E154515
This is a used surplus item that is untested
 

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
Are you sure about which is the primary and which is the secondary? Looks to me like you have it backwards.
Why do you think the wire resistance is meaningful?
It's out of a UPS, so I think the white/black at tp of picture was the output - 2 wires, through a rectifier to the batteries. Not certain, but seemed most likely. Otherwise where would all those wires at the bottom go in what's essentially a giant charger? But I'm a moron with electronics, so there's that as well.

Wire resistance tested to see if I could identify one of them as a center tap by having the values different. But they are all so close I can't tell whats up.
 

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
The top 4 conductors appear to be the typical dual primary, parallel or series, e.g. 120v 240v
Parallel version shown.
Max.
They are joined together - so both whites are crimped into the same eye connector, and both blacks are crimped in a single eye connecter. No way to feed the sets separately.
 

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
Oh, in case it's useful- top wires 10AWG connected to a winding that's 1.52mm diameter (including the coating). The bottom wires are all 14AWG connected to windings of 1.7mm. (Measured with a digital caliper)
 

SamR

Joined Mar 19, 2019
2,412
I'm pretty sure the 10GA is the primary. Put 10VAC on the10GA BLK and WHT and measure what you get out.
 

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
OK - feeding 10v into paired black and white 10AWG wires :

First off my voltage into the house is wiggly and all I have is a variac. So input was varying up and down around the 10v mark by a few tenths and results are only accurate to whatever the wobble was at the moment.

Blue to Black > 41.5v - tested on all all blue/black combos

Blue to Yellow > 10.24v - tested on all blue/yellow combos

Blue to White > 43.4v - again all combos of these two colors

Yellow to Black > 52.3v all combos

White to Yellow > 33.2v all combos

White to Black > 87v

Same color to same color got 0.00X millivolt readings
 
Last edited:

SamR

Joined Mar 19, 2019
2,412
Hmm... I'd measure the V from each to ground but sure suggests the 10GA is the secondary going to a rectifier. Definitely odd to me. And this out of a UPS? Do you have 120VAC or 240VAC supply where you live?
 

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
Hmm... I'd measure the V from each to ground but sure suggests the 10GA is the secondary going to a rectifier. Definitely odd to me. And this out of a UPS? Do you have 120VAC or 240VAC supply where you live?
We're nominally 230v here in New Zealand... but as I said it's pretty wobbly delivery so it's always up and down *around* 230v.

And yeah, I thought at the start that the white/black joined 10AWG was the output not the input, but I don't know enough to know what I don't know, if ya know what I mean... I'm totally out of my depth every time I do electronic stuff.

Edit: Yes, it was removed from a fairly big UPS that had external battery banks.
 

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
Continuity, screaming beeps:
Blue>Yellow, both sets and across sets
Black>White, both sets and across sets

Other combos, no screaming beeps just crickets.

So can I feed it power on white/black OR yellow/blue?
Can I feed it power on both pairs, with white and yellow both to Neutral and black and blue both to Phase?
 

SamR

Joined Mar 19, 2019
2,412
If you don't know what you are doing, you are going to get into dangerous trouble with a transformer. It looks like BLK and WHT are the for the primary input @ 240 and the output, You got ~1:9 ratio so with 240VAC in /9 you are getting ~27VAC out to the rectifier. The other wires/winding had other uses by the UPS. That's my take on it at least. YMMV The 240VAC input also solves a bit of mystery as to why there was 14GA on the input instead of 10GA.
Good luck, time for me to call it a very late nite.
 

Thread Starter

MrBinNZ

Joined Aug 13, 2019
11
Still hoping someone can explain the wiring on this to me.
Happy to perform suggested tests as long as I have adequate equipment.

Testing SamR's above idea-

Feeding 230v Mains to wire 1 and wire 10 gives:
27v on the primary-side blue/yellow pairs
27v on the secondary-side white/black

So seems he was right there.

So seems those 27v outputs gets turned into ~24v through some rectifiers, the 14AWG one on the device side and the big 10AWG output goes out to the batteries?

But what is up with the jumpers between transformers?
 

nsaspook

Joined Aug 27, 2009
7,478
Still hoping someone can explain the wiring on this to me.
Happy to perform suggested tests as long as I have adequate equipment.

Testing SamR's above idea-

Feeding 230v Mains to wire 1 and wire 10 gives:
27v on the primary-side blue/yellow pairs
27v on the secondary-side white/black

So seems he was right there.

So seems those 27v outputs gets turned into ~24v through some rectifiers, the 14AWG one on the device side and the big 10AWG output goes out to the batteries?

But what is up with the jumpers between transformers?
As a UPS output transformer I suspect it was used similar to this type of Modified Sinewave configuration.
https://sound-au.com/articles/inverters.htm


 
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