Need help to find correct transformer


Need help to find toroidal transformer
Pri 120v
Sec 12v (20.8A)

Hello Greg, Welcome to the Forum.
With the specs that were given for that Transformer Please take a look at 237-2051-ND as an option that would match the specs.
Please let us know if you have any questions.

It looks like good choice , one think it may not feet into fixture

123.00mm Dia , I have about 118 mm

Another question I have only one secondary, what would I do with extras ?
Tape them off?

With the part 237-2051-ND according to the Datasheet, for the scondary to get the 12 VAC output you will have the output on the Black and Yellow wires. The Red and Orange wires will be tied together.

Thank you Paul,
Just measured space will fit , but going to be tight.
I checked installation , looks like will have to jumper input and output to get 120/12

Can you tell me if this one VPT12-20800 will not work

The transformer VPT12-20800 states the Primary voltage is 115Vac. This also shows the same specs and a little smaller diameter that might make it fit better.
I would say yes that it will work. The 115Vac and 120Vac usually are referred to as the same like in your home when you plug something into the outlet. They are referred to as 110, 115 or 120VAC.


Thank you for your help

Hi Paul,

Installed unit 237-2051-ND, fit very tight as it is not straight circle. Unit runs very hot and become noisy after 15-20 minutes. What would be suggestions?
Would I be able to exchange it to VPT12-20800 which is smaller?
Would return and new unit require extra shipping cost?


Hello Greg,
It is possible to exchange the part for the other one. That will have to be a decision from our customer service department.
However, I am curious to know why it is getting hot and noisy. May I ask what it is hooked up to or what it is powering? Maybe there is something else that might be going on also. Did the old one just fail, stop working, or get hot at all?


Transformer powering 10 X 20 watt halogen bulbs fixture
Previous transformer was working for over 20 years. It is more sentimental value for this fixture as it cost more to fix then to buy new one.
Place for for transformer is metal enclosure ( like a can) with halls , ones you see on sealing with hanging wire on the bottom going to 10 bulbs.
I will include picture


The old one just stop working, if it was getting hot at the end I didn’t notice. But it stop working while lamp was on with no sound or any other symptoms.

Is the noise it makes a humming sound or more of a rattle type sound?

Humming sound

I have a feeling that the hum may be part of the transformer in general. They may cause a little hum, but with it being really tight in the case that may amplify the hum a little more.
I do not know if you have a way to have the transformer out of the case, in free air, to test it. Of cource being safe about the voltages. Otherwise to insulate the walls of the case is a possible try, but if it is tight that might not work. Maybe the smaller diameter might be a possible option.

One other thing to check also if the transformer is getting warm is the rest of the lights.
Are the bulbs, based and wires in good condition so they are not trying to draw more power than needed.

Switched bulbs to new, same result


Will try to exchange and let you know. Thanks for you help.