Re: [Phys-l] Step down transformer trouble

["Paul Lulai" <plulai@stanthony.k12.mn.us>]

Responses below:
 1.) Had it been working for a while and then failed or is the door bell new and never worked right?
It has never worked correctly.  We replaced it with a please knock sign when our kids were of the napping age.

1 1/2.) Does the transformer fail immediately on being placed in the circuit?
It works for roughly 5 minutes.

2.) Any new electrical work in the house?
None since we've moved in.  But, it didn't work when we moved in.  I thought it would be a 10 minute fix.

3.) Have you checked the doorbell switch(s) circuit to see if the the resistance is basically infinite when the button is not pushed?
I've used the continuity checking function of my multi-meter.  No beeps usually = no connection.

4.) Is it a simple door bell circuit? That is it a simple loop of the secondary the switch the bell and back to the secondary.
I hope so.  That is all I've seen.

5.) Have you tried installing just the primary side of the transformer for a while to see if it blows the transformer with nothing on the secondary?
Nope.  Not a bad idea.

6.) Does the current rating of the transformer match the current rating of the bell? 
Yes, they match.



Paul Lulai
Physics Teacher
St Anthony Village Senior High
3303 33rd Ave 
St Anthony Village MN 55418

(w) 612-706-1146




----- Reply message -----
From: "Roger Haar" <haar@physics.arizona.edu>
Date: Wed, Jul 6, 2011 10:58 am
Subject: [Phys-l] Step down transformer trouble
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>

Dear Paul,

	A bunch of questions:

1.) Had it been working for a while and
then failed or is the door bell new and
never worked right?

1 1/2.) Does the transformer fail immediately
on being placed in the circuit?

2.) Any new electrical work in the house?

3.) Have you checked the doorbell switch(s)
  circuit to see if the the resistance is
  basically infinite when the button is not
  pushed?

4.)  Is it a simple door bell circuit?  That
  is it a simple loop of the secondary the
  switch the bell and back to the secondary.

5.)  Have you tried installing just the primary
side of the transformer for a while to see if
it blows the transformer with nothing on the secondary?

6.)  Does the current rating of the transformer
match the current rating of the bell?

Thanks,
   Roger
========================================
On 7/6/2011 8:37 AM, Dr. Keith S. Taber wrote:
> Just a thought, but is the 16V measured on open circuit, or when the
> bell is connected up?
>
> Keith
>
>
>
> At 05:58 -0400 6/7/11, Paul Lulai wrote:
> > Hi.
> > We can't keep our doorbell stepdown transformer working.  I thought
> > i would check this group for thoughts.
> > The transformer drops to 16v.  That matches the input for our
> > doorbell. The transformer is connected to ground and both the black
> > and white house wires (as directed on installation instructions).
> > It is installed onto a standard junction box with (which has a cfl
> > attached).
> > I've changed transformers multiple times.  I checked the doorbell.
> > I found no problem, but thought a $20 change of bells might so it,
> > so I changed it anyway (after the 2nd transformer).
> > Any thoughts?
> >
> > Paul Lulai
> > Physics Teacher
> > St Anthony Village Senior High
> > 3303 33rd Ave
> > St Anthony Village MN 55418
> >
> > (w) 612-706-1146
> >
> >
> > _______________________________________________
> > Forum for Physics Educators
> > Phys-l@carnot.physics.buffalo.edu
> > https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
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