"Steve Turner" wrote in message ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram) he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):


http://www.trane.com/webcache/un/fur...7_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the 115V
circuit is open (again). If you didn't see my first thread, this is
the third transformer the unit has blown. In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it wasn't
a proper replacement (poor quality, made in China, etc.). This
third unit is most certainly a proper replacement, and it's most
certainly indicative of a real problem I have somewhere else in the
unit. I didn't see any such charring on the previous two units, at
least not like this.

I never got a real chance to test out the system after installing
this third transformer. We had cool weather for several days, and I
never tried to force the system to come on so I could monitor it;
that was probably a mistake. Unfortunately, I was also absent from
the premises during the extended times when the unit was most likely
operational, so that didn't help either. However, my family tells me
that it WAS working and cooling the house rather nicely, for at
least a day, perhaps two. I'm getting 115V in all the right places,
so it doesn't look like an over-voltage condition to me. Perhaps
it's an overheating condition? It looks to me like the only real
load on this circuit is the blower motor; could the motor be causing
this? The blower spins freely when I turn it by hand. Start
capacitor on the motor maybe? Relay on the control board perhaps?


Just a thought,

When you put the new transformer in does the "Diagnostic Light" LED
turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test with
test equipment.

robb

"robb" wrote in
m:

"Steve Turner" wrote in message ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram) he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):



http://www.trane.com/webcache/un/fur...oduct/22-1666-
07_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the 115V
circuit is open (again). If you didn't see my first thread, this is
the third transformer the unit has blown. In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it wasn't
a proper replacement (poor quality, made in China, etc.). This
third unit is most certainly a proper replacement, and it's most
certainly indicative of a real problem I have somewhere else in the
unit. I didn't see any such charring on the previous two units, at
least not like this.

I never got a real chance to test out the system after installing
this third transformer. We had cool weather for several days, and I
never tried to force the system to come on so I could monitor it;
that was probably a mistake. Unfortunately, I was also absent from
the premises during the extended times when the unit was most likely
operational, so that didn't help either. However, my family tells me
that it WAS working and cooling the house rather nicely, for at
least a day, perhaps two. I'm getting 115V in all the right places,
so it doesn't look like an over-voltage condition to me. Perhaps
it's an overheating condition? It looks to me like the only real
load on this circuit is the blower motor; could the motor be causing
this? The blower spins freely when I turn it by hand. Start
capacitor on the motor maybe? Relay on the control board perhaps?

a bad start cap would not affect the 24v control transformer,that just
powers the controller board and relays.
either something is loading the transformer or a problem with input
voltage.


Just a thought,

When you put the new transformer in does the "Diagnostic Light" LED
turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test with
test equipment.

robb



a line voltage monitor may be needed to see if there's some short-term
overvoltage applied to the transformer,and a oscilloscope may determine if
the input waveform is sinusoidal or otherwise,because 60hz iron core
tranformers don't like extreme distortion on their input,it gets converted
to heat,not output voltage. a DMM will not show line distortion or short
term overvoltages.
are the wires burned close to the transformer,or over their entire length?

--
Jim Yanik
jyanik
at
localnet
dot com

On Sat, 09 Apr 2011 19:29:30 -0500, Jim Yanik
wrote:

"robb" wrote in
om:

"Steve Turner" wrote in message ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram) he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):



http://www.trane.com/webcache/un/fur...oduct/22-1666-
07_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the 115V
circuit is open (again). If you didn't see my first thread, this is
the third transformer the unit has blown. In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it wasn't
a proper replacement (poor quality, made in China, etc.). This
third unit is most certainly a proper replacement, and it's most
certainly indicative of a real problem I have somewhere else in the
unit. I didn't see any such charring on the previous two units, at
least not like this.

I never got a real chance to test out the system after installing
this third transformer. We had cool weather for several days, and I
never tried to force the system to come on so I could monitor it;
that was probably a mistake. Unfortunately, I was also absent from
the premises during the extended times when the unit was most likely
operational, so that didn't help either. However, my family tells me
that it WAS working and cooling the house rather nicely, for at
least a day, perhaps two. I'm getting 115V in all the right places,
so it doesn't look like an over-voltage condition to me. Perhaps
it's an overheating condition? It looks to me like the only real
load on this circuit is the blower motor; could the motor be causing
this? The blower spins freely when I turn it by hand. Start
capacitor on the motor maybe? Relay on the control board perhaps?

a bad start cap would not affect the 24v control transformer,that just
powers the controller board and relays.
either something is loading the transformer or a problem with input
voltage.


Or just another crappy transformer.
You do not just ASSume it is the transformer


Just a thought,

When you put the new transformer in does the "Diagnostic Light" LED
turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test with
test equipment.

robb



a line voltage monitor may be needed to see if there's some short-term
overvoltage applied to the transformer,and a oscilloscope may determine if
the input waveform is sinusoidal or otherwise,because 60hz iron core
tranformers don't like extreme distortion on their input,it gets converted
to heat,not output voltage. a DMM will not show line distortion or short
term overvoltages.
are the wires burned close to the transformer,or over their entire length?

Transient overvoltages of less than 20% or there-abouts are unlikely
to blow the transformer primary of the furnace without manifesting
themselves elsewhere in the house - and over 20% would definitely
manifest themselves elsewhere.

On 4/9/2011 7:29 PM, Jim Yanik wrote:
wrote in
m:

"Steve Turner" wrote in message ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram) he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):



http://www.trane.com/webcache/un/fur...oduct/22-1666-
07_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the 115V
circuit is open (again). If you didn't see my first thread, this is
the third transformer the unit has blown. In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it wasn't
a proper replacement (poor quality, made in China, etc.). This
third unit is most certainly a proper replacement, and it's most
certainly indicative of a real problem I have somewhere else in the
unit. I didn't see any such charring on the previous two units, at
least not like this.

I never got a real chance to test out the system after installing
this third transformer. We had cool weather for several days, and I
never tried to force the system to come on so I could monitor it;
that was probably a mistake. Unfortunately, I was also absent from
the premises during the extended times when the unit was most likely
operational, so that didn't help either. However, my family tells me
that it WAS working and cooling the house rather nicely, for at
least a day, perhaps two. I'm getting 115V in all the right places,
so it doesn't look like an over-voltage condition to me. Perhaps
it's an overheating condition? It looks to me like the only real
load on this circuit is the blower motor; could the motor be causing
this? The blower spins freely when I turn it by hand. Start
capacitor on the motor maybe? Relay on the control board perhaps?

a bad start cap would not affect the 24v control transformer,that just
powers the controller board and relays.
either something is loading the transformer or a problem with input
voltage.


Just a thought,

When you put the new transformer in does the "Diagnostic Light" LED
turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test with
test equipment.

robb



a line voltage monitor may be needed to see if there's some short-term
overvoltage applied to the transformer,and a oscilloscope may determine if
the input waveform is sinusoidal or otherwise,because 60hz iron core
tranformers don't like extreme distortion on their input,it gets converted
to heat,not output voltage. a DMM will not show line distortion or short
term overvoltages.
are the wires burned close to the transformer,or over their entire length?

I peeled the insulation back from the hot and neutral wires and the burning
only occurred right at the terminals, no more than 1/4" into the wiring.

Steve Turner wrote:
On 4/9/2011 7:29 PM, Jim Yanik wrote:
wrote in
m:

"Steve Turner" wrote in message ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram) he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):



http://www.trane.com/webcache/un/fur...oduct/22-1666-
07_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the 115V
circuit is open (again). If you didn't see my first thread, this is
the third transformer the unit has blown. In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it wasn't
a proper replacement (poor quality, made in China, etc.). This
third unit is most certainly a proper replacement, and it's most
certainly indicative of a real problem I have somewhere else in the
unit. I didn't see any such charring on the previous two units, at
least not like this.

I never got a real chance to test out the system after installing
this third transformer. We had cool weather for several days, and I
never tried to force the system to come on so I could monitor it;
that was probably a mistake. Unfortunately, I was also absent from
the premises during the extended times when the unit was most likely
operational, so that didn't help either. However, my family tells me
that it WAS working and cooling the house rather nicely, for at
least a day, perhaps two. I'm getting 115V in all the right places,
so it doesn't look like an over-voltage condition to me. Perhaps
it's an overheating condition? It looks to me like the only real
load on this circuit is the blower motor; could the motor be causing
this? The blower spins freely when I turn it by hand. Start
capacitor on the motor maybe? Relay on the control board perhaps?

a bad start cap would not affect the 24v control transformer,that just
powers the controller board and relays.
either something is loading the transformer or a problem with input
voltage.


Just a thought,

When you put the new transformer in does the "Diagnostic Light" LED
turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test with
test equipment.

robb



a line voltage monitor may be needed to see if there's some short-term
overvoltage applied to the transformer,and a oscilloscope may
determine if
the input waveform is sinusoidal or otherwise,because 60hz iron core
tranformers don't like extreme distortion on their input,it gets
converted
to heat,not output voltage. a DMM will not show line distortion or short
term overvoltages.
are the wires burned close to the transformer,or over their entire
length?

I peeled the insulation back from the hot and neutral wires and the
burning only occurred right at the terminals, no more than 1/4" into the
wiring.


So the problem is the joint of the transformer wiring to the lugs. They
may have cold solder joints, or the lug may be slightly loose - enough
to crack the solder connection over time. Your transformer may still be
good!

When you are examining the transformer wire make sure it is stripped
enough to get good solder coverage. Burn off the insulation (enamel) -
do not sand, scrape, or try to erode it because if you scratch the wire
it will break at the scratch.

Re-solder the transformer connectors after first making sure the wire
has at least two complete wraps around the solder lug and the solder
makes a good meniscus joint to the wire and lug. Also use a good grade
of solder, not regular 60/40, find some 63/37 solder (Kester is best) -
this solder resists cold solder joints due to movement when cooling by
solidifying very fast.

John :-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

"robb"


Yep, My A/C unit blew another transformer. Pictures (and wiring diagram)
he

http://www.flickr.com/photos/bbqboye...7626457562742/

http://www.trane.com/webcache/un/fur...7_04012009.pdf

As you can probably see in the pictures, there is visible charring of the
115V leads going into the transformer, and of course the 115V circuit is
open (again).


** From the damage to the tranny visible in the photos - the primary has
developed an internal short ( due to insulation failure) and since there is
no fuse link in series, the resulting current was high enough to make an
exposed wire leading to the terminals explode.

An internal short could develop due to heat alone because of an overload on
the tranny - but this requires a fault to exist on the secondary side which
seems not to be the case.

High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of thing.
So also could back emfs from the blower fan if the is a bad connection in
the AC supply feed.

I suggest you provide the next replacement for that vulnerable tranny with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the tranny
from harm.



...... Phil

On Sat, 09 Apr 2011 20:55:37 -0500, Steve Turner wrote:

On 4/9/2011 7:29 PM, Jim Yanik wrote:
wrote in
m:

"Steve Turner" wrote in message ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram) he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):



http://www.trane.com/webcache/un/fur...oduct/22-1666-
07_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the 115V
circuit is open (again). If you didn't see my first thread, this is
the third transformer the unit has blown. In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it wasn't
a proper replacement (poor quality, made in China, etc.). This
third unit is most certainly a proper replacement, and it's most
certainly indicative of a real problem I have somewhere else in the
unit. I didn't see any such charring on the previous two units, at
least not like this.

I never got a real chance to test out the system after installing
this third transformer. We had cool weather for several days, and I
never tried to force the system to come on so I could monitor it;
that was probably a mistake. Unfortunately, I was also absent from
the premises during the extended times when the unit was most likely
operational, so that didn't help either. However, my family tells me
that it WAS working and cooling the house rather nicely, for at
least a day, perhaps two. I'm getting 115V in all the right places,
so it doesn't look like an over-voltage condition to me. Perhaps
it's an overheating condition? It looks to me like the only real
load on this circuit is the blower motor; could the motor be causing
this? The blower spins freely when I turn it by hand. Start
capacitor on the motor maybe? Relay on the control board perhaps?

a bad start cap would not affect the 24v control transformer,that just
powers the controller board and relays.
either something is loading the transformer or a problem with input
voltage.


Just a thought,

When you put the new transformer in does the "Diagnostic Light" LED
turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test with
test equipment.

robb



a line voltage monitor may be needed to see if there's some short-term
overvoltage applied to the transformer,and a oscilloscope may determine if
the input waveform is sinusoidal or otherwise,because 60hz iron core
tranformers don't like extreme distortion on their input,it gets converted
to heat,not output voltage. a DMM will not show line distortion or short
term overvoltages.
are the wires burned close to the transformer,or over their entire length?

I peeled the insulation back from the hot and neutral wires and the burning
only occurred right at the terminals, no more than 1/4" into the wiring.

Is that a dual primary 115V (230V) xformer? Did you wire both primaries
in parallel for 115V operation?

Grant.

"Phil Allison"

firstly an in-line fuse of say 1/4 amp ....


** Must be a "slo-blo" type fuse.



..... Phil

On 4/9/2011 10:22 PM, Phil Allison wrote:
"robb"


Yep, My A/C unit blew another transformer. Pictures (and wiring diagram)
he

http://www.flickr.com/photos/bbqboye...7626457562742/

http://www.trane.com/webcache/un/fur...7_04012009.pdf

As you can probably see in the pictures, there is visible charring of the
115V leads going into the transformer, and of course the 115V circuit is
open (again).


** From the damage to the tranny visible in the photos - the primary has
developed an internal short ( due to insulation failure) and since there is
no fuse link in series, the resulting current was high enough to make an
exposed wire leading to the terminals explode.

An internal short could develop due to heat alone because of an overload on
the tranny - but this requires a fault to exist on the secondary side which
seems not to be the case.

High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of thing.
So also could back emfs from the blower fan if the is a bad connection in
the AC supply feed.

I suggest you provide the next replacement for that vulnerable tranny with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the tranny
from harm.

1 uF sounds a little high.

I would think .01 uF at 400V would be a better bet. Or an MOV (metal
oxide varistor) or three (across the line and then from each side to
ground).

I don't think this is a voltage spike problem though. Voltage spikes
take out other components first.

Jeff



..... Phil

On Apr 9, 8:29*pm, Jim Yanik wrote:
"robb" wrote innews:WfKdnQOvu_d2bz3QnZ2dnUVZ_uadnZ2d@earthlink. com:





"Steve Turner" *wrote in ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. *Pictures (and wiring
diagram) he

* *http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):

http://www.trane.com/webcache/un/fur...oduct/22-1666-
07_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the 115V
circuit is open (again). *If you didn't see my first thread, this is
the third transformer the unit has blown. *In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it wasn't
a proper replacement (poor quality, made in China, etc.). *This
third unit is most certainly a proper replacement, and it's most
certainly indicative of a real problem I have somewhere else in the
unit. *I didn't see any such charring on the previous two units, at
least not like this.

I never got a real chance to test out the system after installing
this third transformer. *We had cool weather for several days, and I
never tried to force the system to come on so I could monitor it;
that was probably a mistake. Unfortunately, I was also absent from
the premises during the extended times when the unit was most likely
operational, so that didn't help either. However, my family tells me
that it WAS working and cooling the house rather nicely, for at
least a day, perhaps two. *I'm getting 115V in all the right places,
so it doesn't look like an over-voltage condition to me. *Perhaps
it's an overheating condition? *It looks to me like the only real
load on this circuit is the blower motor; could the motor be causing
this? *The blower spins freely when I turn it by hand. *Start
capacitor on the motor maybe? *Relay on the control board perhaps?

a bad start cap would not affect the 24v control transformer,that just
powers the controller board and relays.
either something is loading the transformer or a problem with input
voltage.



It also could be powering a thermostat. Some of them will take power
from the transformer circuit. For example, I have a Honeywell
VisionPro
that has an optional 24V connection to power the thermostat, with
batteries then being the backup. Doing it that way allows the display
to be backlit 24/7 too.

Also, it's not unusual to have humdifiers tied into the 24V circuit
too.

Again, he needs to start doing some basic current measurements,
starting at the transformer and find out how much current the whole
thing is drawing and then if it's high, work to isolate it. If the
current
is normal, then I'd put in a 1.5 amp fuse in the secondary
temporarily.
Contrary to the suggestions to use a fast blow, I'd probably just use
a regular one, as whatever is capable of destroying a transformer
should be most capable of opening any fuse.













Just a thought,

When you put the new transformer in does the *"Diagnostic Light" LED
turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" *imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test with
test equipment.

That's a good idea too.





robb

a line voltage monitor may be needed to see if there's some short-term
overvoltage applied to the transformer,and a oscilloscope may determine if
the input waveform is sinusoidal or otherwise,because 60hz iron core
tranformers don't like extreme distortion on their input,it gets converted
to heat,not output voltage.

I don't see how he could have a waveform that is so out of shape that
it
burns up this one specific transformer, yet there are no apparent
complaints of any other problems in the house. Or how you'd get
such a badly distorted waveform in the house in the first place.




a DMM will not show line distortion or short
term overvoltages.
are the wires burned close to the transformer,or over their entire length?

--
Jim Yanik
jyanik
at
localnet
dot com- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

To OP
this is a long shot but...
I noticed on the Trane wiring diagram that you posted that the
connections for the IGNITION circuit are shown to be near to the
connections for the primary of the transformer.

If there is some insulation problem on the ignition wires and the VERY
high voltage from the ignition circuit is sparking or jumping over to
the transformer primary circuit, this could cause the symptoms you are
seeing.

Make sure the wires that are part of the ignition circuit are not even
close to the anything else. and inspect them (with the power off) for
any sigh of cracks or other faults. These have very high voltage
like in a car spark plug and can jump several inches if there is an
insulation problem. And the problem would be intermittent. The
transformer primary voltage would look perfect except when the high
voltage spark jumps over to it and this could easily damage the
insulation on the transformer which is not designed for very high
voltages.

If you are an electrical novice, you may want to think about calling
in for some help at this point.

Mark

"Mark" wrote in message
...
To OP
this is a long shot but...
I noticed on the Trane wiring diagram that you posted that the
connections for the IGNITION circuit are shown to be near to the
connections for the primary of the transformer.
snip
Mark

Everything I see on the diagrams says this is a HSI (Hot Surface
Igniter) type of furnace. There is no high voltage in that type
of igniter.
David

In article ,
Grant wrote:


Is that a dual primary 115V (230V) xformer? Did you wire both primaries
in parallel for 115V operation?

Grant.

This thread started on a.h.r (alt.home.repair) and I'm not sure the OP
monitors s.e.r. Someone cross-posted it here, but the bulk of the thread
(several hundred posts) is on a.h.r. only.

So if you want to be helpful, you might wander over there. ISTR reading
that the OP taped off two wires.

Grant wrote in
:

On Sat, 09 Apr 2011 20:55:37 -0500, Steve Turner
wrote:

On 4/9/2011 7:29 PM, Jim Yanik wrote:
wrote in
m:

"Steve Turner" wrote in message ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram) he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):



http://www.trane.com/webcache/un/fur.../product/22-16
66- 07_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the
115V circuit is open (again). If you didn't see my first thread,
this is the third transformer the unit has blown. In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it
wasn't a proper replacement (poor quality, made in China, etc.).
This third unit is most certainly a proper replacement, and it's
most certainly indicative of a real problem I have somewhere else
in the unit. I didn't see any such charring on the previous two
units, at least not like this.

I never got a real chance to test out the system after installing
this third transformer. We had cool weather for several days, and
I never tried to force the system to come on so I could monitor
it; that was probably a mistake. Unfortunately, I was also absent
from the premises during the extended times when the unit was most
likely operational, so that didn't help either. However, my family
tells me that it WAS working and cooling the house rather nicely,
for at least a day, perhaps two. I'm getting 115V in all the
right places, so it doesn't look like an over-voltage condition to
me. Perhaps it's an overheating condition? It looks to me like
the only real load on this circuit is the blower motor; could the
motor be causing this? The blower spins freely when I turn it by
hand. Start capacitor on the motor maybe? Relay on the control
board perhaps?

a bad start cap would not affect the 24v control transformer,that
just powers the controller board and relays.
either something is loading the transformer or a problem with input
voltage.


Just a thought,

When you put the new transformer in does the "Diagnostic Light"
LED turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test
with test equipment.

robb



a line voltage monitor may be needed to see if there's some
short-term overvoltage applied to the transformer,and a oscilloscope
may determine if the input waveform is sinusoidal or
otherwise,because 60hz iron core tranformers don't like extreme
distortion on their input,it gets converted to heat,not output
voltage. a DMM will not show line distortion or short term
overvoltages. are the wires burned close to the transformer,or over
their entire length?

I peeled the insulation back from the hot and neutral wires and the
burning only occurred right at the terminals, no more than 1/4" into
the wiring.

Is that a dual primary 115V (230V) xformer? Did you wire both
primaries in parallel for 115V operation?

Grant.


another poster on the alt.home.repair NG made that suggestion/comment.
A very good one,that I had overlooked. good catch!

--
Jim Yanik
jyanik
at
localnet
dot com

On Apr 10, 11:55*am, "David" wrote:
"Mark" *wrote in message
...
To OP
this is a long shot but...
I noticed on the Trane wiring diagram that you posted that the
connections for the IGNITION circuit are shown to be near to the
connections for the primary of the transformer.
snip
Mark

Everything I see on the diagrams says this is a HSI (Hot Surface
Igniter) type of furnace. There is no high voltage in that type
of igniter.
David

David,
I think you are right...

well it sounded good anyway....

regards
Mark

"Jeff Thies"
Phil Allison wrote:
"robb"


Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram)
he

http://www.flickr.com/photos/bbqboye...7626457562742/

http://www.trane.com/webcache/un/fur...7_04012009.pdf

As you can probably see in the pictures, there is visible charring of
the
115V leads going into the transformer, and of course the 115V circuit is
open (again).


** From the damage to the tranny visible in the photos - the primary has
developed an internal short ( due to insulation failure) and since there
is
no fuse link in series, the resulting current was high enough to make an
exposed wire leading to the terminals explode.

An internal short could develop due to heat alone because of an overload
on
the tranny - but this requires a fault to exist on the secondary side
which
seems not to be the case.

High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of
thing.
So also could back emfs from the blower fan if the is a bad connection in
the AC supply feed.

I suggest you provide the next replacement for that vulnerable tranny
with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the
tranny
from harm.

1 uF sounds a little high.


** No it ain't.


I would think .01 uF at 400V would be a better bet.

** Think again.

Or an MOV (metal oxide varistor) or three (across the line and then from
each side to ground).

** Bad idea.

I don't think this is a voltage spike problem though. Voltage spikes take
out other components first.

** Not on the AC supply they don't.


...... Phil

On 4/9/2011 10:06 PM, John Robertson wrote:
Steve Turner wrote:
On 4/9/2011 7:29 PM, Jim Yanik wrote:
wrote in
m:

"Steve Turner" wrote in message ...

A continuation of the "Why does the 115V-24V transformer keep
blowing on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram) he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of
the wiring diagrams that I also copied to my above flickr site as
jpg images):



http://www.trane.com/webcache/un/fur...oduct/22-1666-
07_04012009.pdf

As you can probably see in the pictures, there is visible charring
of the 115V leads going into the transformer, and of course the 115V
circuit is open (again). If you didn't see my first thread, this is
the third transformer the unit has blown. In the previous
discussion, it was discussed that perhaps the first one just blew
because of old age (6 years), and the second blew because it wasn't
a proper replacement (poor quality, made in China, etc.). This
third unit is most certainly a proper replacement, and it's most
certainly indicative of a real problem I have somewhere else in the
unit. I didn't see any such charring on the previous two units, at
least not like this.

I never got a real chance to test out the system after installing
this third transformer. We had cool weather for several days, and I
never tried to force the system to come on so I could monitor it;
that was probably a mistake. Unfortunately, I was also absent from
the premises during the extended times when the unit was most likely
operational, so that didn't help either. However, my family tells me
that it WAS working and cooling the house rather nicely, for at
least a day, perhaps two. I'm getting 115V in all the right places,
so it doesn't look like an over-voltage condition to me. Perhaps
it's an overheating condition? It looks to me like the only real
load on this circuit is the blower motor; could the motor be causing
this? The blower spins freely when I turn it by hand. Start
capacitor on the motor maybe? Relay on the control board perhaps?

a bad start cap would not affect the 24v control transformer,that just
powers the controller board and relays.
either something is loading the transformer or a problem with input
voltage.


Just a thought,

When you put the new transformer in does the "Diagnostic Light" LED
turn on ?
Does the LED blink or flash in one of the patterns indicated in the
"diagnostic codes" section that you posted a link to ?

The "diagnostic codes" imply that the control board can detect
several of the problems mentioned by others.
Maybe a good starting point as there is not enough time to test with
test equipment.

robb



a line voltage monitor may be needed to see if there's some short-term
overvoltage applied to the transformer,and a oscilloscope may
determine if
the input waveform is sinusoidal or otherwise,because 60hz iron core
tranformers don't like extreme distortion on their input,it gets
converted
to heat,not output voltage. a DMM will not show line distortion or short
term overvoltages.
are the wires burned close to the transformer,or over their entire
length?

I peeled the insulation back from the hot and neutral wires and the
burning only occurred right at the terminals, no more than 1/4" into
the wiring.


So the problem is the joint of the transformer wiring to the lugs. They
may have cold solder joints, or the lug may be slightly loose - enough
to crack the solder connection over time. Your transformer may still be
good!

When you are examining the transformer wire make sure it is stripped
enough to get good solder coverage. Burn off the insulation (enamel) -
do not sand, scrape, or try to erode it because if you scratch the wire
it will break at the scratch.

Re-solder the transformer connectors after first making sure the wire
has at least two complete wraps around the solder lug and the solder
makes a good meniscus joint to the wire and lug. Also use a good grade
of solder, not regular 60/40, find some 63/37 solder (Kester is best) -
this solder resists cold solder joints due to movement when cooling by
solidifying very fast.

John :-#)#

Hi John, fancy meeting you here! Wait, I didn't realize this is cross
posted to sci.electronics.repair Now I know why you are here. Glad you
liked the package.

Tony

On 4/9/2011 10:22 PM, Phil Allison wrote:
"robb"


Yep, My A/C unit blew another transformer. Pictures (and wiring diagram)
he

http://www.flickr.com/photos/bbqboye...7626457562742/

http://www.trane.com/webcache/un/fur...7_04012009.pdf

As you can probably see in the pictures, there is visible charring of the
115V leads going into the transformer, and of course the 115V circuit is
open (again).


** From the damage to the tranny visible in the photos - the primary has
developed an internal short ( due to insulation failure) and since there is
no fuse link in series, the resulting current was high enough to make an
exposed wire leading to the terminals explode.

An internal short could develop due to heat alone because of an overload on
the tranny - but this requires a fault to exist on the secondary side which
seems not to be the case.

Oh my gawd, someone agrees with me. Looking at the picture says a lot.
Burnt on the primary side, looks like new on the secondary. And this
is the third transformer with an open primary!


I don't know about a the 1uF cap, seems way too high so I'll delete what
was below and pretend I didn't see it.

"Tony Miklos don't know much"


** From the damage to the tranny visible in the photos - the primary has
developed an internal short ( due to insulation failure) and since there
is
no fuse link in series, the resulting current was high enough to make an
exposed wire leading to the terminals explode.

An internal short could develop due to heat alone because of an overload
on
the tranny - but this requires a fault to exist on the secondary side
which
seems not to be the case.

Oh my gawd, someone agrees with me. Looking at the picture says a lot.
Burnt on the primary side, looks like new on the secondary. And this is
the third transformer with an open primary!


I don't know about a the 1uF cap, seems way too high

** Why ?????

It ( likely ) needs to absorb a transient back emf generated by a powerful
blower fan.

Non puny size cap will ever do that and using 1uF cases no harm whatsoever.


so I'll delete what was below and pretend I didn't see it.

** Nothing like doing the old Ostrich trick when the brain gets overloaded.

Wot a jerk off.


..... Phil

Put 3A automotive fuse on secondary. Use light bulb trick to find
shorts. Two 12 V light bulbs in series that draw no more than 40 VA.

On 4/10/2011 7:47 PM, Phil Allison wrote:
"Jeff Thies"
Phil Allison wrote:
"robb"


Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram)
he

http://www.flickr.com/photos/bbqboye...7626457562742/

http://www.trane.com/webcache/un/fur...7_04012009.pdf

As you can probably see in the pictures, there is visible charring of
the
115V leads going into the transformer, and of course the 115V circuit is
open (again).


** From the damage to the tranny visible in the photos - the primary has
developed an internal short ( due to insulation failure) and since there
is
no fuse link in series, the resulting current was high enough to make an
exposed wire leading to the terminals explode.

An internal short could develop due to heat alone because of an overload
on
the tranny - but this requires a fault to exist on the secondary side
which
seems not to be the case.

High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of
thing.
So also could back emfs from the blower fan if the is a bad connection in
the AC supply feed.

I suggest you provide the next replacement for that vulnerable tranny
with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the
tranny
from harm.

1 uF sounds a little high.


** No it ain't.

I thought you had simply misspoke and that this was an honest error.

The reactance of a 1uF cap at 60Hz is: 2652 ohms (1/(2*pi*F*C)
Online calculator:
http://www.kusashi.com/reactance-c.p...&stage=results

V^2/R = W

Assuming primary, as why would you put it on the secondary:

120^2 / 2652 = 5.43 W

Does that not seem wrong to you?

If not then go buy a 200V non polarized 1uF cap. It is no easy chore.

http://search.digikey.com/scripts/Dk...dll?Cat=131081

Jeff

On 4/10/2011 9:47 PM, Jeff Thies wrote:
On 4/10/2011 7:47 PM, Phil Allison wrote:
"Jeff Thies"
Phil Allison wrote:
"robb"


Yep, My A/C unit blew another transformer. Pictures (and wiring
diagram)
he

http://www.flickr.com/photos/bbqboye...7626457562742/

http://www.trane.com/webcache/un/fur...7_04012009.pdf


As you can probably see in the pictures, there is visible charring of
the
115V leads going into the transformer, and of course the 115V
circuit is
open (again).


** From the damage to the tranny visible in the photos - the primary
has
developed an internal short ( due to insulation failure) and since
there
is
no fuse link in series, the resulting current was high enough to
make an
exposed wire leading to the terminals explode.

An internal short could develop due to heat alone because of an
overload
on
the tranny - but this requires a fault to exist on the secondary side
which
seems not to be the case.

High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of
thing.
So also could back emfs from the blower fan if the is a bad
connection in
the AC supply feed.

I suggest you provide the next replacement for that vulnerable tranny
with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the
tranny
from harm.

1 uF sounds a little high.


** No it ain't.

I thought you had simply misspoke and that this was an honest error.

The reactance of a 1uF cap at 60Hz is: 2652 ohms (1/(2*pi*F*C)
Online calculator:
http://www.kusashi.com/reactance-c.p...&stage=results

V^2/R = W

Assuming primary, as why would you put it on the secondary:

120^2 / 2652 = 5.43 W

Does that not seem wrong to you?

If not then go buy a 200V non polarized 1uF cap. It is no easy chore.

I have some big ass mylars, I think they are 4uF @ 200v.

"Jeff Thies"
Phil Allison wrote:

I suggest you provide the next replacement for that vulnerable tranny
with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the
tranny from harm.

1 uF sounds a little high.


** No it ain't.

I thought you had simply misspoke and that this was an honest error.

The reactance of a 1uF cap at 60Hz is: 2652 ohms (1/(2*pi*F*C)
Online calculator:
http://www.kusashi.com/reactance-c.p...&stage=results

V^2/R = W

Assuming primary, as why would you put it on the secondary:

120^2 / 2652 = 5.43 W

Does that not seem wrong to you?

** Completely.

Such a cap dissipates no energy at all.

What planet do you come from ??


If not then go buy a 200V non polarized 1uF cap. It is no easy chore.


** 1uF caps for use across the AC supply are cheap and plentiful.

Typical examples are metallised polypropylene " class X2 " types and sell
for $1 or $2 each.

http://search.digikey.com/scripts/Dk...me=399-5466-ND


What planet do you come from ??



..... Phil

"Tony Miklos"

I have some big ass mylars, I think they are 4uF @ 200v.


** They won't last long if connected across the AC supply.



..... Phil

On 4/10/2011 10:48 PM, Phil Allison wrote:
"Tony Miklos"

I have some big ass mylars, I think they are 4uF @ 200v.


** They won't last long if connected across the AC supply.



.... Phil



I know, I was just about to reply to my post saying that the voltage
rating is VDC.

"Tony Miklos"
Phil Allison wrote:


I have some big ass mylars, I think they are 4uF @ 200v.


** They won't last long if connected across the AC supply.


I know, I was just about to reply to my post saying that the voltage
rating is VDC.


** Film caps rated at 600VDC will generally last a fair while wired across a
120 volt AC supply ( but not with a 240VAC supply ) - but is it far better
to use a purpose designed and agency approved "class X1" or "classX2"
capacitor.




.... Phil

On Sun, 10 Apr 2011 12:22:13 +1000, "Phil Allison"
wrote:


"robb"


Yep, My A/C unit blew another transformer. Pictures (and wiring diagram)
he

http://www.flickr.com/photos/bbqboye...7626457562742/

http://www.trane.com/webcache/un/fur...7_04012009.pdf

As you can probably see in the pictures, there is visible charring of the
115V leads going into the transformer, and of course the 115V circuit is
open (again).


** From the damage to the tranny visible in the photos - the primary has
developed an internal short ( due to insulation failure) and since there is
no fuse link in series, the resulting current was high enough to make an
exposed wire leading to the terminals explode

An internal short could develop due to heat alone because of an overload on
the tranny - but this requires a fault to exist on the secondary side which
seems not to be the case.

High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of thing.
So also could back emfs from the blower fan if the is a bad connection in
the AC supply feed.



I suggest you provide the next replacement for that vulnerable tranny with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the tranny
from harm.



A capacitor across an AC supply??????????????? As a surge
protector????
Have not heard of that before.

A capacitor across the AC line would appear as a load - and could
form a resonant l/ci tank circuit, which would also appear as a low
resistance -causing high current to flow

There are 2 other POSSIBLE issues here though - - -.

Both are perhaps long shots - but mabee worth investigating.

The transformer primary APPEARS to be saturating.
Primary current on an unloaded transformer CAN, in some cases, excede
full load current. Possibly the transformer requires MORE load on the
secondary than it is getting.

An example is a microwave oven transformer. With no load on either the
high voltage or low voltage secondary, the primary will generally
saturate and overheat. If you remove the high voltage secondary and
add your own windings to make a "custom" transformer, it is not
uncommon for the primary to saturate at no/low loads - overheating the
transformer.

Like I said - a long shot, but possibly worth investigating. adding a
small 24 volt pilot light across the secondary MAY solve that kind of
a problem.

The other POSSIBILITY is a DC bias on the primary, which WILL cause
saturation on 1/2 cycle of the AC. Need a scope to check that
effectively - or something like a 10uf nonpolarized capacitor and a
100K ohm 1/2 watt resistor in series across the primary, with a DC
voltmeter connected across the cap. Make all connections BEFORE
turning on the mains power. You should expect to see readings of +/-
approx 25-35mv across the cap in a normal residential situation.

Lets say you read 275mv DC on the line, and the transformer primary
resistance is 2 ohms.. That will put a DC current of 137.5ma through
the primary - which when added to the normal AC current on the one
half cycle will greatly excede the saturation current of the primary.

A half wave rectified load on the same circuit could put a DC
component across the line.

An AC (nonpolarized) capacitor IN SERIES with the primary would
remove the DC component from the primary winding, but finding a
capacitor that would ballast the primary properly (allow full rated
primary current) while not causing a series resonance (which would
appear as a short circuit across the mains) is not something I would
try to calculate.

..... Phil

"Phil Allison"


High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of
thing.
So also could back emfs from the blower fan if the is a bad connection in
the AC supply feed.

I suggest you provide the next replacement for that vulnerable tranny with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the tranny
from harm.



A capacitor across an AC supply??????????????? As a surge
protector????
Have not heard of that before.


** Then your ignorance is showing.

The stated reason for the capacitor was in relation to the "blower fan"
inside the same unit as the small tranny.

The event the cap has to deal with is a back emf surge generated by that
fan when the AC supply is suddenly disconnected - for whatever reason.


A capacitor across the AC line would appear as a load

** Draws 45mA continuously.

Yawnnnnnnn....

- and could form a resonant l/ci tank circuit,

** Yawnnnnnn....

(snip absurd drivel)


There are 2 other POSSIBLE issues here though - - -.

Both are perhaps long shots - but mabee worth investigating.

The transformer primary APPEARS to be saturating.


** The primary appears to be EXPLODING !!

You ridiculous ******.


..... Phil

On 4/10/2011 10:46 PM, Phil Allison wrote:
"Jeff Thies"
Phil Allison wrote:

I suggest you provide the next replacement for that vulnerable tranny
with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the
tranny from harm.

1 uF sounds a little high.


** No it ain't.

I thought you had simply misspoke and that this was an honest error.

The reactance of a 1uF cap at 60Hz is: 2652 ohms (1/(2*pi*F*C)
Online calculator:
http://www.kusashi.com/reactance-c.p...&stage=results

V^2/R = W

Assuming primary, as why would you put it on the secondary:

120^2 / 2652 = 5.43 W

Does that not seem wrong to you?

** Completely.

Such a cap dissipates no energy at all.

What planet do you come from ??

What a jerk you are. You do realize that is 45mA running through that.

Jeff

"Jeff Thies"
Phil Allison wrote:
"Jeff Thies"
Phil Allison wrote:

I suggest you provide the next replacement for that vulnerable tranny
with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous
use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the
tranny from harm.

1 uF sounds a little high.


** No it ain't.

I thought you had simply misspoke and that this was an honest error.

The reactance of a 1uF cap at 60Hz is: 2652 ohms (1/(2*pi*F*C)
Online calculator:
http://www.kusashi.com/reactance-c.p...&stage=results

V^2/R = W

Assuming primary, as why would you put it on the secondary:

120^2 / 2652 = 5.43 W

Does that not seem wrong to you?

** Completely.

Such a cap dissipates no energy at all.

What planet do you come from ??

What a jerk you are. You do realize that is 45mA running through that.


** What sort of know nothing JERK thinks that capacitors dissipate energy
??

Then proceeds to calculate the reactive impedance and treat it the same as
resistance ??

Big bad.

Zero out of ten.


..... Phil

On Mon, 11 Apr 2011 13:25:02 +1000, "Phil Allison"
wrote:



"Phil Allison"


High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of
thing.
So also could back emfs from the blower fan if the is a bad connection in
the AC supply feed.

I suggest you provide the next replacement for that vulnerable tranny with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the tranny
from harm.



A capacitor across an AC supply??????????????? As a surge
protector????
Have not heard of that before.


** Then your ignorance is showing.

The stated reason for the capacitor was in relation to the "blower fan"
inside the same unit as the small tranny.

The event the cap has to deal with is a back emf surge generated by that
fan when the AC supply is suddenly disconnected - for whatever reason.


A capacitor across the AC line would appear as a load

** Draws 45mA continuously.

Yawnnnnnnn....

- and could form a resonant l/ci tank circuit,

** Yawnnnnnn....

(snip absurd drivel)


There are 2 other POSSIBLE issues here though - - -.

Both are perhaps long shots - but mabee worth investigating.

The transformer primary APPEARS to be saturating.


** The primary appears to be EXPLODING !!

You ridiculous ******.


.... Phil

Phil - your mamma should wash your mouth out with soap.
I SAID the other two scenarios were long shots - but so is everything
else that has been suggested. The windings of the trasnformer do not
APPEAR to be overheated - looks like just blackened at the connections
between the winding and the connecting wires.

It is definitely a strange failure - and I don't think it has been
properly analyzed to determine exactly what/where the problem is.
As Arthur Conan Doyle said, "after you have eliminated all the
possibilities, whatever remains, however improbable, must be the
truth"

** The primary appears to be EXPLODING !!

You ridiculous ******.

Phil - your mamma should wash your mouth out with soap.


** You need to get your hands off of it.


I SAID the other two scenarios were long shots ..

** And I said they were ridiculous drivel.

- but so is everything else that has been suggested.

** Your opinion is based on your ignorance only.

The windings of the trasnformer do not
APPEAR to be overheated - looks like just blackened at the connections
between the winding and the connecting wires.


** See the vaporised metal coating deposited on the plastic cover next to
the tranny?

That is a damn EXPLOSION !!

It happened very suddenly and made a loud bang too.

I said:

" High voltage spikes on the primary could also cause insulation failure
leading to the damage seen in the pics - lightning does this sort of thing.
So also could back emfs from the blower fan if the is a bad connection in
the AC supply feed."

If the insulation on the enamel wire of the primary is punctured by a HIGH
VOLTAGE SPIKE, effectively shorting out most of the primary - then the
120 AC supply ( no fuse exists remember ) will easily turn the two exposed
wire ends into metal vapour !!!

Cos they just became the fuses.

It just so happens that many small transformers made in China, India & Sri
Lanka etc are very prone to this sort of failure - due to bad manufacturing
practices.



..... Phil

What is this "old light bulb trick"?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Ron D." wrote in message
...
Put 3A automotive fuse on secondary. Use light bulb trick
to find
shorts. Two 12 V light bulbs in series that draw no more
than 40 VA.

"Stormin Mormon"

What is this "old light bulb trick"?


** You need to ask Agent 86 that one....




.... Phil

On 4/10/2011 11:29 PM, Phil Allison wrote:
"Jeff Thies"
Phil Allison wrote:
"Jeff Thies"
Phil Allison wrote:

I suggest you provide the next replacement for that vulnerable tranny
with
some "protection" - firstly an in-line fuse of say 1/4 amp AND a
capacitor wired across the primary of say 1uF rated for continuous
use
across the AC supply.

If there is an overload on the tranny, the fuse will blow.

The 1uF capacitor should suppress spike voltages enough to save the
tranny from harm.

1 uF sounds a little high.


** No it ain't.

I thought you had simply misspoke and that this was an honest error.

The reactance of a 1uF cap at 60Hz is: 2652 ohms (1/(2*pi*F*C)
Online calculator:
http://www.kusashi.com/reactance-c.p...&stage=results

V^2/R = W

Assuming primary, as why would you put it on the secondary:

120^2 / 2652 = 5.43 W

Does that not seem wrong to you?

** Completely.

Such a cap dissipates no energy at all.

What planet do you come from ??

What a jerk you are. You do realize that is 45mA running through that.


** What sort of know nothing JERK thinks that capacitors dissipate energy
??

It doesn't have to dissipate energy to explode. That is a lot of joules.

Then proceeds to calculate the reactive impedance and treat it the same as
resistance ??

Big bad.

So I left out the PF, so what?

Zero out of ten.

My first encounter with you, but no doubt others have had the same
reaction. Telling an inexperienced OP to put in a 1mF cap without any
specifics, and that for the dubious goal of "suppressing" the back EMF
of a motor running off the line has a disconnect from reality.
Transformers are generally much hardier devices than the solid state
components they feed.

Say what you want. You've already made your mark and I really don't
care what you add. I've taken away what I need to know about yourself,
and the OP is off somewhere else.

Happy now?

Jeff


.... Phil

In article ,
Jeff Thies wrote:

My first encounter with you

Jeff, since you don't hang out on s.e.r., I'll clue you in about Phil.
Regardless of what he knows or doesn't know, he calls everyone a
****wit, and worse, all the time. Virtually every sentence of every post
is chock full of derision. If you choose to dialogue with him, you'll
get great heaping portions of his demented abuse. So don't take it
personally.

On 4/11/2011 11:25 AM, Smitty Two wrote:
In ,
Jeff wrote:

My first encounter with you

Jeff, since you don't hang out on s.e.r., I'll clue you in about Phil.
Regardless of what he knows or doesn't know, he calls everyone a
****wit, and worse, all the time. Virtually every sentence of every post
is chock full of derision. If you choose to dialogue with him, you'll
get great heaping portions of his demented abuse. So don't take it
personally.

Thanks. That's about what I surmised. A North American version of Rod
Speed.

Some people I'll read consistently, I'll put him in the other group.

Jeff

On 4/11/2011 8:25 AM Smitty Two spake thus:

In article ,
Jeff Thies wrote:

My first encounter with you

Jeff, since you don't hang out on s.e.r., I'll clue you in about Phil.
Regardless of what he knows or doesn't know, he calls everyone a
****wit, and worse, all the time. Virtually every sentence of every post
is chock full of derision. If you choose to dialogue with him, you'll
get great heaping portions of his demented abuse. So don't take it
personally.

That's true, and it's also true that he often acts--seriously, no
joke--like he's off his meds.

But it's also true that he knows more about electronics than probably
all the "experts" here (a.h.r.) put together. And it is possible to
engage him in serious dialog on electronic topics, as shown by recent
threads in s.e.r. So while he can be abusive, you ought to listen to his
technical advice, which is golden.


--
The current state of literacy in our advanced civilization:

yo
wassup
nuttin
wan2 hang
k
where
here
k
l8tr
by

- from Usenet (what's *that*?)

On Mon, 11 Apr 2011 11:30:33 -0700, David Nebenzahl wrote:

On 4/11/2011 8:25 AM Smitty Two spake thus:

In article ,
Jeff Thies wrote:

My first encounter with you

Jeff, since you don't hang out on s.e.r., I'll clue you in about Phil.
Regardless of what he knows or doesn't know, he calls everyone a
****wit, and worse, all the time. Virtually every sentence of every
post is chock full of derision. If you choose to dialogue with him,
you'll get great heaping portions of his demented abuse. So don't take
it personally.

That's true, and it's also true that he often acts--seriously, no
joke--like he's off his meds.

But it's also true that he knows more about electronics than probably
all the "experts" here (a.h.r.) put together.

That's debatable. Phil is a troll with decent knowledge in electronics.
He sets traps like a spider spins a web then comes back to pounce on
those in the trap. I think Phil gets a lot of his knowledge on Google.



--
Live Fast Die Young, Leave A Pretty Corpse

On 4/11/2011 1:46 PM, Meat Plow wrote:
On Mon, 11 Apr 2011 11:30:33 -0700, David Nebenzahl wrote:

On 4/11/2011 8:25 AM Smitty Two spake thus:

In ,
Jeff wrote:

My first encounter with you

Jeff, since you don't hang out on s.e.r., I'll clue you in about Phil.
Regardless of what he knows or doesn't know, he calls everyone a
****wit, and worse, all the time. Virtually every sentence of every
post is chock full of derision. If you choose to dialogue with him,
you'll get great heaping portions of his demented abuse. So don't take
it personally.

That's true, and it's also true that he often acts--seriously, no
joke--like he's off his meds.

But it's also true that he knows more about electronics than probably
all the "experts" here (a.h.r.) put together.

That's debatable. Phil is a troll with decent knowledge in electronics.
He sets traps like a spider spins a web then comes back to pounce on
those in the trap. I think Phil gets a lot of his knowledge on Google.


Google? Is that some new kind of mind altering drug? ^_^

TDD