Large Scale Central

Help troubleshooting a transformer

Electronics
#1

I acquired a 120VAC ~ 12-18VDC transformer I was hoping to use as a source for accessories on my indoor layout. I can not read any voltage at the output terminals. It does not read any open conductors on the primary or the secondary sides, nor do I read any short to the core on either side.

How simply can this be? I must be missing something.

#2

It puts out DC? Then there’s got to be a diode or bridge. Maybe that’s blown?

#3
david said:
Help troubleshooting a transformer...
Take .45 ACP, insert loaded magazine, point said .45 ACP in general direction of sick transformer...
#4

There should be no “trouble” “shooting” a defective transformer using Steve’s succinct instructions.

It’s defective unless your meter, the ac plug, or you are defective. (just kidding on the last)

Regards, Greg

#5

Thanks Steve and Greg. Considering what I paid for said transformer, I may as well get some enjoyment out of it.

P.S. OT, have you ever played .22 caliber golf? Man do those golf balls fly when hit right. I even got a hole-in-one. snicker**snicker

#6

Post some pictures? Where are you measuring output?

#7
Joe Satnik said:
Post some pictures? Where are you measuring output?
Yeah! I'd like to see a video of .22 caliber golf. That would be cool!
#8

I removed the windings from the enclosure. The component has two input leads, one leg fused and 3 output leads.

The fuse is not open, the leads are not open none of the leads short to the core.

http://www.lscdata.com/users/lastmanout/_forumfiles/TXcore.bmp

#9
Steve Featherkile said:
Joe Satnik said:
Post some pictures? Where are you measuring output?
Yeah! I'd like to see a video of .22 caliber golf. That would be cool!
This really isn't me, heck it's not a .22, but it is a hoot.

http://www.youtube.com/watch?v=nAqKwMCpJTQ

#10

Do you have a Volt/Ohm/Amp meter? I assume you do. Have you measured the resistance of the primary coil and the secondary coils? Depending on your meter, as the flux builds the resistance should go up.

Also, you could remove the fuse and measure the amperage draw of the primary.

These steps will at least prove the coils are in okay shape.

#11

David,

Excellent diagram.

How many ohms across the primary?

How many ohms 12 to commmon? 18 to common? 12 to 18?

Any leakage between any of the primary leads and any of the secondary leads? (Should look “open circuit” to an ohm-meter.)

Thanks.

Joe Satnik

#12

Dear David,

Hope you knew “unpowered circuit only” when measuring resistance.

Hope your meter had a fast acting fuse if you didn’t.

Sincerely,

Joe Satnik

#13

One thing that has not been explicitly mentioned.

From your drawing this is a 110v transformer with a tapped secondary.

The output MUST be AC, unless you have hidden a bridge rectifier in the diagram.

Yet the thread starts out saying 12-18 volt DC… I hope you used your AC setting on your meter!

Maybe the whole problem is that you are trying to measure AC using your DC meter setting, which will probably result in nothing on the meter.

Regards, Greg

#14

I agree with Greg. You do not show a bridge circuit converting AC to DC. The transformer is probably AC out, and you need to measure AC with your meter. If it is set on DC you will at best get a sporatic voltage reading…
Good Luck, Russ

#15

I thought you’d have blasted it by now. Anyone for C4?

#16

A/C, A/C DUH!!!

I’ll go stand in the corner now.

#17

Occam’s Razor

Greg

#18
David Hill said:
A/C, A/C DUH!!!

I’ll go stand in the corner now.


Dave,
I’ve had a few “brain farts” myself…but never one that lasted 12 days :lol:
Ralph

#19

It must be that all those brain cells I fried in the 60’s and 70’s are now catching up to me.

#20

:smiley: :smiley: :smiley:

You’re doing great if it’s just starting to catch up to you now :wink:
I think it caught up to me about 20 years ago :lol:
Ralph