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-   -   Doorbell Transformer 24v keeps burning out (http://www.diychatroom.com/f18/doorbell-transformer-24v-keeps-burning-out-162839/)

heynowjerry 11-10-2012 01:16 PM

Doorbell Transformer 24v keeps burning out
 
Doorbell and Driveway magnet (for triggering doorbell when car drives over) have been working for 10 years. 16v transformer burned out, so replaced with 16/24v unit from Home Depot.

Stopped working after a few weeks, and no reading from Multitester. Replaced with new one, and stopped working again after a few weeks.

Do i go back to 16vac or is there another issue?

Thanks in advance.

Jerry

raylo32 11-10-2012 01:42 PM

Sounds like there may be a short in your wiring that is frying the transformer.

heynowjerry 11-10-2012 02:08 PM

Quote:

Originally Posted by raylo32 (Post 1048956)
Sounds like there may be a short in your wiring that is frying the transformer.

Thanks much.

So that would take weeks for the short to knock out the transformer? I wouldn't notice right away?

And I should be able to test the incoming doorbell feed and driveway feed and notice the short?

Thanks again..

raylo32 11-10-2012 02:14 PM

Not sure why it would be intermittent but a short is more believbale to me than 2 defective transformers in 2 weeks. Where/how does the wire run out to the driveway? Does it get perturbed in any way? Also, it's possible the contact set on the driveway or the doorbell ringer is the culprit. Get out a meter and start checking stuff....

bobelectric 11-10-2012 06:19 PM

Look into getting a wireless driveway alarm.

Bobka 11-10-2012 08:21 PM

open up and inspect the plunger unit...you may have a bad solenoid..it is sticking and drawing current....grease and or dirt build up will make her sticky....try replacing the whole nine yards..:thumbsup:

dmxtothemax 11-11-2012 12:20 AM

Are you really sure that the replacement transformer has the correct current capacity ?

heynowjerry 11-12-2012 08:35 AM

Quote:

Originally Posted by dmxtothemax (Post 1049420)
Are you really sure that the replacement transformer has the correct current capacity ?


Actually, the chime unit is new, and working fine, or so it seems. The transformer is a dual 16/24, dependent on wiring.

The previous unit was 16 only, worked for 10 years, although after chiming would buzz for 2-4 seconds afterward. Finally, the plunger stuck and I bought another unit. Driveway worked like a charm for 10 years. THis is really confusing.

:)

dmxtothemax 11-12-2012 07:13 PM

Do you know for sure what the current draw is for the new unit ?
If for instance the new unit needs 2 amps,
and your transformer is rated for 1 amp,
then this would explain the burn outs !
Trannys burn out for two main reasons,
1 - Faulty construction.
2 - Overloaded.

Try putting a amp meter on the tranny and measure
what currents are flowing.

joed 11-12-2012 08:36 PM

Quote:

Originally Posted by heynowjerry (Post 1050216)
The previous unit was 16 only, worked for 10 years, although after chiming would buzz for 2-4 seconds afterward. Finally, the plunger stuck and I bought another unit.

Would seem to indicate you have a sticking button or shorting cable. Probable cause for burning out transformers.

heynowjerry 11-13-2012 07:16 AM

Quote:

Originally Posted by dmxtothemax (Post 1050719)
Do you know for sure what the current draw is for the new unit ?
If for instance the new unit needs 2 amps,
and your transformer is rated for 1 amp,
then this would explain the burn outs !
Trannys burn out for two main reasons,
1 - Faulty construction.
2 - Overloaded.

Try putting a amp meter on the tranny and measure
what currents are flowing.

Appreciate the responses.

I'm going to show my newbie experience.

'Putting an amp meter on the tranny'
So i assume since i have already shown that the transformer was showing ~24v when it was good, i need to measure something else. I have only the 2 lines coming into the transformer, so i need to measure those two? What am i looking for?

Thanks

COLDIRON 11-13-2012 07:17 AM

Make sure the VA reading on the transformer is the same as the original.

dmxtothemax 11-13-2012 10:00 PM

Use your multi meter, set to "AC AMPS"
Usually this involves moving the red lead to a different socket
on the multi meter,
as well as a different position for the switch.
Take one wire off the tranny,
connect one of the multi meter leads to the tranny,
the other lead of the meter goes to the wire that was
connectted to the tranny.
The meter should now be in "SERIES" with the load.
Double check that the switch is correct on the meter
and that the leads are in the correct socket to measure amps.

Now turn the system on !
What current is flowing during operation ?
and what current flows when not in use ?

Report your findings !

heynowjerry 11-17-2012 09:25 AM

1 Attachment(s)
Quote:

Originally Posted by dmxtothemax (Post 1051735)
Use your multi meter, set to "AC AMPS"
Usually this involves moving the red lead to a different socket
on the multi meter,
as well as a different position for the switch.
Take one wire off the tranny,
connect one of the multi meter leads to the tranny,
the other lead of the meter goes to the wire that was
connectted to the tranny.
The meter should now be in "SERIES" with the load.
Double check that the switch is correct on the meter
and that the leads are in the correct socket to measure amps.

Now turn the system on !
What current is flowing during operation ?
and what current flows when not in use ?

Report your findings !

Reporting my findings. My multimeter only handles DC Amps, so i need to get a better unit that handles AC Amps.

COLDIRON 11-17-2012 04:34 PM

This is a recording did you check the VA rating on the transformer to make sure it's the same as the original?? Got to have the right parts before testing. 1 step at a time.


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