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** Be real smart for the OP to purchase some OTHER 120/24 volt tranny andJust mentioned elsewhere that I have a new transformer on order and I
can't
really do anything until that arrives. Rest assured I appreciate all the
input
and I'm taking it all into consideration. Thanks.
You bought the fuses, right?
I DON'T want to hear about another blown transformer.
Then still it is not right. Let;s go back from begining. How old"Vic Smith"
Steve Turner
Just mentioned elsewhere that I have a new transformer on order and I
can't
really do anything until that arrives. Rest assured I appreciate all the
input
and I'm taking it all into consideration. Thanks.
You bought the fuses, right?
I DON'T want to hear about another blown transformer.
** Be real smart for the OP to purchase some OTHER 120/24 volt tranny and
use it.
The things are a dime a dozen.
And fit a "slo-blo" 1/4 amp fuse to the primary.
.... Phil
Hmmm,
What is fuse gonna do? Instead of blowing x-former,, blow fuses?
Sure you could. You could open up those other two transformers and checkJust mentioned elsewhere that I have a new transformer on order and I can't
really do anything until that arrives.
** Be real smart for the OP to purchase some OTHER 120/24 volt tranny
and
use it.
The things are a dime a dozen.
And fit a "slo-blo" 1/4 amp fuse to the primary.
What is fuse gonna do?
Instead of blowing x-former,, blow fuses?
** Then you can find the cause of the overload - cos the tranny stillThen still it is not right.
Hi Steve,On 4/13/2011 10:51 PM, John Robertson wrote:
Steve Turner wrote:
On 4/9/2011 7:29 PM, Jim Yanik wrote:
"robb"<some@where.on.net> wrote in
news:WfKdnQOvu_d2bz3QnZ2dnUVZ_uadnZ2d@earthlink.com:
"Steve Turner" wrote in message news:inoakf$qin$1@dont-email.me...
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) here:
http://www.flickr.com/photos/bbqboyee/sets/72157626457562742/
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/furnaces%20%28furn%29/product/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,
Not to be rude or anything, but a LOT of talk has gone on about your
problem
and I have not seen any further posts from you on the matter. No
comments about
any suggestions at all.
I'm not going to spend any more time on this thread until we hear back
from the
original poster with more information otherwise we are simply blowing
smoke
(sorry - couldn't resist).
John :-#)#
Just mentioned elsewhere that I have a new transformer on order and I
can't really do anything until that arrives. Rest assured I appreciate
all the input and I'm taking it all into consideration. Thanks.
With such indication even as described here giving low indication asOn 4/12/2011 9:23 PM Don Klipstein spake thus:
I have yet to look at these diagrams, but is the circuit board
powered by this tranny shown to "board level" as opposed to "component
level"? If so, then the board can have, probably does have, a rectifier
not shown in the diagram.
With all the pontificating you've been doing here, Don, I would've
thought you'd at least had glanced at the wiring diagrams the OP posted,
way up there somewhere. Sheesh.
The controller is shown as a block. It most certainly has at least one
rectifier on it, as it contains electronics that no doubt requires DC
power to operate. Thought you'd have figured it out. (Not just a relay
board.)
In <4da54b91$0$26215$822641b3@news.adtechcomputers.com>, D Nebenzahl wrote:
On 4/12/2011 9:23 PM Don Klipstein spake thus:
I have yet to look at these diagrams, but is the circuit board
powered by this tranny shown to "board level" as opposed to "component
level"? If so, then the board can have, probably does have, a rectifier
not shown in the diagram.
With all the pontificating you've been doing here, Don, I would've
thought you'd at least had glanced at the wiring diagrams the OP posted,
way up there somewhere. Sheesh.
The controller is shown as a block. It most certainly has at least one
rectifier on it, as it contains electronics that no doubt requires DC
power to operate. Thought you'd have figured it out. (Not just a relay
board.)
With such indication even as described here giving low indication as
to rectification having a 1-component bridge rectifier, 4 discrete diodes,
a fed-with-center-tap 2-diode fullwave scheme, 2 separate diodes or a
single 3-lead dual-diode used for that...
If the controller is only shown as a block, how well does it show the
rectifier scheme, as in whether the rectifier's diodes are discrete
individual diodes or integrated into one rectifier package?
If anyone here sees that noted to such extent that it's not a waste of
my time to take a look there, please pipe up!
Phil Allison wrote:
"Vic Smith"
Steve Turner
Just mentioned elsewhere that I have a new transformer on order and I
can't
really do anything until that arrives. Rest assured I appreciate all the
input
and I'm taking it all into consideration. Thanks.
You bought the fuses, right?
I DON'T want to hear about another blown transformer.
** Be real smart for the OP to purchase some OTHER 120/24 volt tranny and
use it.
The things are a dime a dozen.
And fit a "slo-blo" 1/4 amp fuse to the primary.
.... Phil
Hmmm,
What is fuse gonna do? Instead of blowing x-former,, blow fuses?
Then still it is not right. Let;s go back from begining. How old
is the system? When this blowing tranny started? From day 1 or some
time(month, years after the system is installed? If tranny is hot to
touch when in use, that is rad flag.
The design of the first transformer makes it virtually impossible to open it upIn article<io5tea$b6u$1@dont-email.me>,
Steve Turner<bbqboyee@swtacobell.net.invalid> wrote:
Just mentioned elsewhere that I have a new transformer on order and I can't
really do anything until that arrives.
Sure you could. You could open up those other two transformers and check
for an open thermal fuse. As I recall, you said neither of them failed
in the same manner as the third. I still say you could have 3 distinct,
unrelated failures.
Just because you can't fix something, it doesn't mean that failureOn 4/14/2011 12:41 AM, Smitty Two wrote:
In article<io5tea$b6u$1@dont-email.me>,
Steve Turner<bbqboyee@swtacobell.net.invalid> wrote:
Just mentioned elsewhere that I have a new transformer on order and I
can't
really do anything until that arrives.
Sure you could. You could open up those other two transformers and check
for an open thermal fuse. As I recall, you said neither of them failed
in the same manner as the third. I still say you could have 3 distinct,
unrelated failures.
The design of the first transformer makes it virtually impossible to open it
up
(remove the tape) without destroying the windings, (which I did) so there is
no
possibility of "repairing" it by installing a thermal fuse (as some
suggested).
There is evidence of burning at the input contactors just like there is on
the third transformer (the one I took pictures of), but not quite as bad. I
wouldn't call it an "explosion". There is no evidence of a thermal fuse.
On the second transformer (a completely different brand and style) there was
no
evidence of burning. Again, it too was virtually impossible to open up with
destroying it, so I didn't bother. However, because everyone has been so
curious, I just did open it up (destroying it in the process) and there IS a
thermal fuse on the input side; it is open, which explains why there is no
burning.
The third transformer is similar to the first in design (except for the extra
208 and 240 legs, which, per the instructions, I taped off and ignored). It
is
also virtually impossible to remove the tape to gain access to the primary
windings without breaking through the wires, but I did, and again there is no
evidence of a thermal fuse.
I see no reason to conclude there are "3 distinct, unrelated failures".
Others sorta concluded that for me. It was "Made in China" and has a bit of aIn article<io785f$t86$1@dont-email.me>,
Steve Turner<bbqboyee@swtacobell.net.invalid> wrote:
On 4/14/2011 12:41 AM, Smitty Two wrote:
In article<io5tea$b6u$1@dont-email.me>,
Steve Turner<bbqboyee@swtacobell.net.invalid> wrote:
Just mentioned elsewhere that I have a new transformer on order and I
can't
really do anything until that arrives.
Sure you could. You could open up those other two transformers and check
for an open thermal fuse. As I recall, you said neither of them failed
in the same manner as the third. I still say you could have 3 distinct,
unrelated failures.
The design of the first transformer makes it virtually impossible to open it
up
(remove the tape) without destroying the windings, (which I did) so there is
no
possibility of "repairing" it by installing a thermal fuse (as some
suggested).
There is evidence of burning at the input contactors just like there is on
the third transformer (the one I took pictures of), but not quite as bad. I
wouldn't call it an "explosion". There is no evidence of a thermal fuse.
On the second transformer (a completely different brand and style) there was
no
evidence of burning. Again, it too was virtually impossible to open up with
destroying it, so I didn't bother. However, because everyone has been so
curious, I just did open it up (destroying it in the process) and there IS a
thermal fuse on the input side; it is open, which explains why there is no
burning.
The third transformer is similar to the first in design (except for the extra
208 and 240 legs, which, per the instructions, I taped off and ignored). It
is
also virtually impossible to remove the tape to gain access to the primary
windings without breaking through the wires, but I did, and again there is no
evidence of a thermal fuse.
I see no reason to conclude there are "3 distinct, unrelated failures".
Just because you can't fix something, it doesn't mean that failure
analysis is moot. I'd be doing serious exploratory surgery on all 3 of
those transformers to try to understand what the hell happened.
I'm not "concluding" that there are 3 distinct unrelated failures, I'm
suggesting it as a possibility.
The first, OEM transformer lasted 6 years. The second transformer lasted
a few days, and by your own admission was a cheap knockoff that may not
have been suited for your application at all.
I brought the old transformer to a local HVAC supply house, and the salesAnd the 3rd transformer may well have failed due to improper wiring, or
a loose connection leading to excessive current leading to insulation
breakdown and a hard short, or as has been suggested repeatedly, a fault
somewhere on the secondary side.
You've also agreed that there are wire color discrepancies and several
respondents have opined that both halves of the primary should, perhaps,
have been wired in parallel to accommodate the current requirements.
I'm sorry you feel that I'm not "doing" anything or that I'm leaving youSo, I too am curious, have you acquired some appropriate fuses, figured
out how to monitor the current, and been able to schedule some time off
from your other responsibilities so that you can actually work through
this puzzle once the new xformer arrives? Are you equipped to bench test
the new transformer to verify wiring color scheme before you install it?
Do you know how to test that bridge rectifier? Seems like you have a
*lot* you could be doing while waiting for the UPS guy.
Which instructions are those? You're not putting in an OEM transformer,I chose to connect the transformer
according to the instructions, and not according to any speculation "opined"
in
this group.
Yep, I'll do that. It's only in cooling mode that the transformers haveOn Apr 14, 2:37 pm, Steve Turner<bbqbo...@swtacobell.net.invalid
wrote:
On 4/14/2011 12:06 PM, Smitty Two wrote:
In article<io785f$t8...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
On 4/14/2011 12:41 AM, Smitty Two wrote:
In article<io5tea$b6...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
Just mentioned elsewhere that I have a new transformer on order and I
can't
really do anything until that arrives.
Sure you could. You could open up those other two transformers and check
for an open thermal fuse. As I recall, you said neither of them failed
in the same manner as the third. I still say you could have 3 distinct,
unrelated failures.
The design of the first transformer makes it virtually impossible to open it
up
(remove the tape) without destroying the windings, (which I did) so there is
no
possibility of "repairing" it by installing a thermal fuse (as some
suggested).
There is evidence of burning at the input contactors just like there is on
the third transformer (the one I took pictures of), but not quite as bad. I
wouldn't call it an "explosion". There is no evidence of a thermal fuse.
On the second transformer (a completely different brand and style) there was
no
evidence of burning. Again, it too was virtually impossible to open up with
destroying it, so I didn't bother. However, because everyone has been so
curious, I just did open it up (destroying it in the process) and there IS a
thermal fuse on the input side; it is open, which explains why there is no
burning.
The third transformer is similar to the first in design (except for the extra
208 and 240 legs, which, per the instructions, I taped off and ignored). It
is
also virtually impossible to remove the tape to gain access to the primary
windings without breaking through the wires, but I did, and again there is no
evidence of a thermal fuse.
I see no reason to conclude there are "3 distinct, unrelated failures".
Just because you can't fix something, it doesn't mean that failure
analysis is moot. I'd be doing serious exploratory surgery on all 3 of
those transformers to try to understand what the hell happened.
I'm not "concluding" that there are 3 distinct unrelated failures, I'm
suggesting it as a possibility.
The first, OEM transformer lasted 6 years. The second transformer lasted
a few days, and by your own admission was a cheap knockoff that may not
have been suited for your application at all.
Others sorta concluded that for me. It was "Made in China" and has a bit of a
different form factor, but that's the only evidence I have so say it might not
have been "suitable". The transformer was similarly rated, and internally it
doesn't look much different from the others, so I still have no real reason to
believe it shouldn't have worked.
And the 3rd transformer may well have failed due to improper wiring, or
a loose connection leading to excessive current leading to insulation
breakdown and a hard short, or as has been suggested repeatedly, a fault
somewhere on the secondary side.
You've also agreed that there are wire color discrepancies and several
respondents have opined that both halves of the primary should, perhaps,
have been wired in parallel to accommodate the current requirements.
I brought the old transformer to a local HVAC supply house, and the sales
person (whom I perceived to be at least somewhat of an expert), gave me the
third transformer as a suitable replacment. I chose to connect the transformer
according to the instructions, and not according to any speculation "opined" in
this group.
So, I too am curious, have you acquired some appropriate fuses, figured
out how to monitor the current, and been able to schedule some time off
from your other responsibilities so that you can actually work through
this puzzle once the new xformer arrives? Are you equipped to bench test
the new transformer to verify wiring color scheme before you install it?
Do you know how to test that bridge rectifier? Seems like you have a
*lot* you could be doing while waiting for the UPS guy.
I'm sorry you feel that I'm not "doing" anything or that I'm leaving you
hanging, but I'll be making the repairs on my own schedule, as time permits.
My own place of employ has me working 12 and 16 hour days, so I can't be
everywhere at once. Plus, the weather here is pleasant and there's been no
real need to run the air conditioner, and the house has two A/C units anyway so
I'm in no hurry. I don't have the fuses or fuse holders yet, but the
transformer isn't going in without them, so it will be taken care of. My
common sense tells me that I really shouldn't *have* to test and verify the
living daylights out of a new transformer, but I will most certainly get
bitched out here if I don't, so yes, that will be done. I don't really recall
the discussion about the bridge rectifier, but I'll look for it. I will be
reviewing the entire discussion and make a checklist of all the steps I need to
perform.
Anything else?- Hide quoted text -
- Show quoted text -
After you put it in, measure the current and voltages in both
the primary and secondary. I'd measure them both with the
AC running and with it not running.
Also, not sure if anyone ever covered this, but when the transformers
have failed have they all been in cooling mode, heating, or both?
Steve, As said before the best thing to do is to fuse both the primaryOn 4/14/2011 2:54 PM, trader4@optonline.net wrote:
On Apr 14, 2:37 pm, Steve Turner<bbqbo...@swtacobell.net.invalid
wrote:
On 4/14/2011 12:06 PM, Smitty Two wrote:
In article<io785f$t8...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
On 4/14/2011 12:41 AM, Smitty Two wrote:
In article<io5tea$b6...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
Just mentioned elsewhere that I have a new transformer on order
and I
can't
really do anything until that arrives.
Sure you could. You could open up those other two transformers and
check
for an open thermal fuse. As I recall, you said neither of them
failed
in the same manner as the third. I still say you could have 3
distinct,
unrelated failures.
The design of the first transformer makes it virtually impossible
to open it
up
(remove the tape) without destroying the windings, (which I did) so
there is
no
possibility of "repairing" it by installing a thermal fuse (as some
suggested).
There is evidence of burning at the input contactors just like
there is on
the third transformer (the one I took pictures of), but not quite
as bad. I
wouldn't call it an "explosion". There is no evidence of a thermal
fuse.
On the second transformer (a completely different brand and style)
there was
no
evidence of burning. Again, it too was virtually impossible to
open up with
destroying it, so I didn't bother. However, because everyone has
been so
curious, I just did open it up (destroying it in the process) and
there IS a
thermal fuse on the input side; it is open, which explains why
there is no
burning.
The third transformer is similar to the first in design (except for
the extra
208 and 240 legs, which, per the instructions, I taped off and
ignored). It
is
also virtually impossible to remove the tape to gain access to the
primary
windings without breaking through the wires, but I did, and again
there is no
evidence of a thermal fuse.
I see no reason to conclude there are "3 distinct, unrelated
failures".
Just because you can't fix something, it doesn't mean that failure
analysis is moot. I'd be doing serious exploratory surgery on all 3 of
those transformers to try to understand what the hell happened.
I'm not "concluding" that there are 3 distinct unrelated failures, I'm
suggesting it as a possibility.
The first, OEM transformer lasted 6 years. The second transformer
lasted
a few days, and by your own admission was a cheap knockoff that may not
have been suited for your application at all.
Others sorta concluded that for me. It was "Made in China" and has a
bit of a
different form factor, but that's the only evidence I have so say it
might not
have been "suitable". The transformer was similarly rated, and
internally it
doesn't look much different from the others, so I still have no real
reason to
believe it shouldn't have worked.
And the 3rd transformer may well have failed due to improper wiring, or
a loose connection leading to excessive current leading to insulation
breakdown and a hard short, or as has been suggested repeatedly, a
fault
somewhere on the secondary side.
You've also agreed that there are wire color discrepancies and several
respondents have opined that both halves of the primary should,
perhaps,
have been wired in parallel to accommodate the current requirements.
I brought the old transformer to a local HVAC supply house, and the
sales
person (whom I perceived to be at least somewhat of an expert), gave
me the
third transformer as a suitable replacment. I chose to connect the
transformer
according to the instructions, and not according to any speculation
"opined" in
this group.
So, I too am curious, have you acquired some appropriate fuses, figured
out how to monitor the current, and been able to schedule some time off
from your other responsibilities so that you can actually work through
this puzzle once the new xformer arrives? Are you equipped to bench
test
the new transformer to verify wiring color scheme before you install
it?
Do you know how to test that bridge rectifier? Seems like you have a
*lot* you could be doing while waiting for the UPS guy.
I'm sorry you feel that I'm not "doing" anything or that I'm leaving you
hanging, but I'll be making the repairs on my own schedule, as time
permits.
My own place of employ has me working 12 and 16 hour days, so I can't be
everywhere at once. Plus, the weather here is pleasant and there's
been no
real need to run the air conditioner, and the house has two A/C units
anyway so
I'm in no hurry. I don't have the fuses or fuse holders yet, but the
transformer isn't going in without them, so it will be taken care
of. My
common sense tells me that I really shouldn't *have* to test and
verify the
living daylights out of a new transformer, but I will most certainly get
bitched out here if I don't, so yes, that will be done. I don't
really recall
the discussion about the bridge rectifier, but I'll look for it. I
will be
reviewing the entire discussion and make a checklist of all the steps
I need to
perform.
Anything else?- Hide quoted text -
- Show quoted text -
After you put it in, measure the current and voltages in both
the primary and secondary. I'd measure them both with the
AC running and with it not running.
Also, not sure if anyone ever covered this, but when the transformers
have failed have they all been in cooling mode, heating, or both?
Yep, I'll do that. It's only in cooling mode that the transformers have
failed, but I'm in Texas and we're long past the point where we'll be
needing the heater for a while, so it's hard to say whether or not
running the heat would also trigger the problem.
After you put it in, measure the current and voltages in bothOn 4/14/2011 12:06 PM, Smitty Two wrote:
In article<io785f$t8...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
On 4/14/2011 12:41 AM, Smitty Two wrote:
In article<io5tea$b6...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
Just mentioned elsewhere that I have a new transformer on order and I
can't
really do anything until that arrives.
Sure you could. You could open up those other two transformers and check
for an open thermal fuse. As I recall, you said neither of them failed
in the same manner as the third. I still say you could have 3 distinct,
unrelated failures.
The design of the first transformer makes it virtually impossible to open it
up
(remove the tape) without destroying the windings, (which I did) so there is
no
possibility of "repairing" it by installing a thermal fuse (as some
suggested).
There is evidence of burning at the input contactors just like there is on
the third transformer (the one I took pictures of), but not quite as bad. I
wouldn't call it an "explosion". There is no evidence of a thermal fuse.
On the second transformer (a completely different brand and style) there was
no
evidence of burning. Again, it too was virtually impossible to open up with
destroying it, so I didn't bother. However, because everyone has been so
curious, I just did open it up (destroying it in the process) and there IS a
thermal fuse on the input side; it is open, which explains why there is no
burning.
The third transformer is similar to the first in design (except for the extra
208 and 240 legs, which, per the instructions, I taped off and ignored). It
is
also virtually impossible to remove the tape to gain access to the primary
windings without breaking through the wires, but I did, and again there is no
evidence of a thermal fuse.
I see no reason to conclude there are "3 distinct, unrelated failures"..
Just because you can't fix something, it doesn't mean that failure
analysis is moot. I'd be doing serious exploratory surgery on all 3 of
those transformers to try to understand what the hell happened.
I'm not "concluding" that there are 3 distinct unrelated failures, I'm
suggesting it as a possibility.
The first, OEM transformer lasted 6 years. The second transformer lasted
a few days, and by your own admission was a cheap knockoff that may not
have been suited for your application at all.
Others sorta concluded that for me. It was "Made in China" and has a bit of a
different form factor, but that's the only evidence I have so say it might not
have been "suitable". The transformer was similarly rated, and internally it
doesn't look much different from the others, so I still have no real reason to
believe it shouldn't have worked.
And the 3rd transformer may well have failed due to improper wiring, or
a loose connection leading to excessive current leading to insulation
breakdown and a hard short, or as has been suggested repeatedly, a fault
somewhere on the secondary side.
You've also agreed that there are wire color discrepancies and several
respondents have opined that both halves of the primary should, perhaps,
have been wired in parallel to accommodate the current requirements.
I brought the old transformer to a local HVAC supply house, and the sales
person (whom I perceived to be at least somewhat of an expert), gave me the
third transformer as a suitable replacment. I chose to connect the transformer
according to the instructions, and not according to any speculation "opined" in
this group.
So, I too am curious, have you acquired some appropriate fuses, figured
out how to monitor the current, and been able to schedule some time off
from your other responsibilities so that you can actually work through
this puzzle once the new xformer arrives? Are you equipped to bench test
the new transformer to verify wiring color scheme before you install it?
Do you know how to test that bridge rectifier? Seems like you have a
*lot* you could be doing while waiting for the UPS guy.
I'm sorry you feel that I'm not "doing" anything or that I'm leaving you
hanging, but I'll be making the repairs on my own schedule, as time permits.
My own place of employ has me working 12 and 16 hour days, so I can't be
everywhere at once. Plus, the weather here is pleasant and there's been no
real need to run the air conditioner, and the house has two A/C units anyway so
I'm in no hurry. I don't have the fuses or fuse holders yet, but the
transformer isn't going in without them, so it will be taken care of. My
common sense tells me that I really shouldn't *have* to test and verify the
living daylights out of a new transformer, but I will most certainly get
bitched out here if I don't, so yes, that will be done. I don't really recall
the discussion about the bridge rectifier, but I'll look for it. I will be
reviewing the entire discussion and make a checklist of all the steps I need to
perform.
Anything else?- Hide quoted text -
- Show quoted text -
Giving up for real solution? Just band aid fix? VChanging blown x-formerSteve Turner wrote:
On 4/14/2011 2:54 PM, trader4@optonline.net wrote:
On Apr 14, 2:37 pm, Steve Turner<bbqbo...@swtacobell.net.invalid
wrote:
On 4/14/2011 12:06 PM, Smitty Two wrote:
In article<io785f$t8...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
On 4/14/2011 12:41 AM, Smitty Two wrote:
In article<io5tea$b6...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
Just mentioned elsewhere that I have a new transformer on order
and I
can't
really do anything until that arrives.
Sure you could. You could open up those other two transformers
and check
for an open thermal fuse. As I recall, you said neither of them
failed
in the same manner as the third. I still say you could have 3
distinct,
unrelated failures.
The design of the first transformer makes it virtually impossible
to open it
up
(remove the tape) without destroying the windings, (which I did)
so there is
no
possibility of "repairing" it by installing a thermal fuse (as some
suggested).
There is evidence of burning at the input contactors just like
there is on
the third transformer (the one I took pictures of), but not quite
as bad. I
wouldn't call it an "explosion". There is no evidence of a thermal
fuse.
On the second transformer (a completely different brand and style)
there was
no
evidence of burning. Again, it too was virtually impossible to
open up with
destroying it, so I didn't bother. However, because everyone has
been so
curious, I just did open it up (destroying it in the process) and
there IS a
thermal fuse on the input side; it is open, which explains why
there is no
burning.
The third transformer is similar to the first in design (except
for the extra
208 and 240 legs, which, per the instructions, I taped off and
ignored). It
is
also virtually impossible to remove the tape to gain access to the
primary
windings without breaking through the wires, but I did, and again
there is no
evidence of a thermal fuse.
I see no reason to conclude there are "3 distinct, unrelated
failures".
Just because you can't fix something, it doesn't mean that failure
analysis is moot. I'd be doing serious exploratory surgery on all 3 of
those transformers to try to understand what the hell happened.
I'm not "concluding" that there are 3 distinct unrelated failures, I'm
suggesting it as a possibility.
The first, OEM transformer lasted 6 years. The second transformer
lasted
a few days, and by your own admission was a cheap knockoff that may
not
have been suited for your application at all.
Others sorta concluded that for me. It was "Made in China" and has a
bit of a
different form factor, but that's the only evidence I have so say it
might not
have been "suitable". The transformer was similarly rated, and
internally it
doesn't look much different from the others, so I still have no real
reason to
believe it shouldn't have worked.
And the 3rd transformer may well have failed due to improper
wiring, or
a loose connection leading to excessive current leading to insulation
breakdown and a hard short, or as has been suggested repeatedly, a
fault
somewhere on the secondary side.
You've also agreed that there are wire color discrepancies and several
respondents have opined that both halves of the primary should,
perhaps,
have been wired in parallel to accommodate the current requirements.
I brought the old transformer to a local HVAC supply house, and the
sales
person (whom I perceived to be at least somewhat of an expert), gave
me the
third transformer as a suitable replacment. I chose to connect the
transformer
according to the instructions, and not according to any speculation
"opined" in
this group.
So, I too am curious, have you acquired some appropriate fuses,
figured
out how to monitor the current, and been able to schedule some time
off
from your other responsibilities so that you can actually work through
this puzzle once the new xformer arrives? Are you equipped to bench
test
the new transformer to verify wiring color scheme before you
install it?
Do you know how to test that bridge rectifier? Seems like you have a
*lot* you could be doing while waiting for the UPS guy.
I'm sorry you feel that I'm not "doing" anything or that I'm leaving
you
hanging, but I'll be making the repairs on my own schedule, as time
permits.
My own place of employ has me working 12 and 16 hour days, so I
can't be
everywhere at once. Plus, the weather here is pleasant and there's
been no
real need to run the air conditioner, and the house has two A/C
units anyway so
I'm in no hurry. I don't have the fuses or fuse holders yet, but the
transformer isn't going in without them, so it will be taken care
of. My
common sense tells me that I really shouldn't *have* to test and
verify the
living daylights out of a new transformer, but I will most certainly
get
bitched out here if I don't, so yes, that will be done. I don't
really recall
the discussion about the bridge rectifier, but I'll look for it. I
will be
reviewing the entire discussion and make a checklist of all the
steps I need to
perform.
Anything else?- Hide quoted text -
- Show quoted text -
After you put it in, measure the current and voltages in both
the primary and secondary. I'd measure them both with the
AC running and with it not running.
Also, not sure if anyone ever covered this, but when the transformers
have failed have they all been in cooling mode, heating, or both?
Yep, I'll do that. It's only in cooling mode that the transformers
have failed, but I'm in Texas and we're long past the point where
we'll be needing the heater for a while, so it's hard to say whether
or not running the heat would also trigger the problem.
Steve, As said before the best thing to do is to fuse both the primary
and secondary windings.
If you have the recommended (original) transformer ratings handy that
should make it easy to figure out. For example, if the secondary (24VAC
as I recall) is rated at 1A, then the primary fuse is 1/5 of that
(24:120 - plus a fudge factor) suggesting that a 0.25A slo-blo should
last fairly well, and a 1A slo-blo on the secondary winding. If the
secondary is rated at 2A, then I'd go with a 0.5A slo-blo on the
primary, along with a 2A slo-blo on the secondary.
Two fuse holders should be fine - one for the 120VAC side and one for
the 24VAC side.
Hope this helps - at least it will reduce the cost of replacing
transformers!
John :-#)#
Hi,
blowing the transformer while finding the real problem.John Robertson wrote:
Steve Turner wrote:
On 4/14/2011 2:54 PM, trader4@optonline.net wrote:
On Apr 14, 2:37 pm, Steve Turner<bbqbo...@swtacobell.net.invalid
wrote:
On 4/14/2011 12:06 PM, Smitty Two wrote:
In article<io785f$t8...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
On 4/14/2011 12:41 AM, Smitty Two wrote:
In article<io5tea$b6...@dont-email.me>,
Steve Turner<bbqbo...@swtacobell.net.invalid> wrote:
Just mentioned elsewhere that I have a new transformer on order
and I
can't
really do anything until that arrives.
Sure you could. You could open up those other two transformers
and check
for an open thermal fuse. As I recall, you said neither of them
failed
in the same manner as the third. I still say you could have 3
distinct,
unrelated failures.
The design of the first transformer makes it virtually impossible
to open it
up
(remove the tape) without destroying the windings, (which I did)
so there is
no
possibility of "repairing" it by installing a thermal fuse (as some
suggested).
There is evidence of burning at the input contactors just like
there is on
the third transformer (the one I took pictures of), but not quite
as bad. I
wouldn't call it an "explosion". There is no evidence of a thermal
fuse.
On the second transformer (a completely different brand and style)
there was
no
evidence of burning. Again, it too was virtually impossible to
open up with
destroying it, so I didn't bother. However, because everyone has
been so
curious, I just did open it up (destroying it in the process) and
there IS a
thermal fuse on the input side; it is open, which explains why
there is no
burning.
The third transformer is similar to the first in design (except
for the extra
208 and 240 legs, which, per the instructions, I taped off and
ignored). It
is
also virtually impossible to remove the tape to gain access to the
primary
windings without breaking through the wires, but I did, and again
there is no
evidence of a thermal fuse.
I see no reason to conclude there are "3 distinct, unrelated
failures".
Just because you can't fix something, it doesn't mean that failure
analysis is moot. I'd be doing serious exploratory surgery on all 3 of
those transformers to try to understand what the hell happened.
I'm not "concluding" that there are 3 distinct unrelated failures, I'm
suggesting it as a possibility.
The first, OEM transformer lasted 6 years. The second transformer
lasted
a few days, and by your own admission was a cheap knockoff that may
not
have been suited for your application at all.
Others sorta concluded that for me. It was "Made in China" and has a
bit of a
different form factor, but that's the only evidence I have so say it
might not
have been "suitable". The transformer was similarly rated, and
internally it
doesn't look much different from the others, so I still have no real
reason to
believe it shouldn't have worked.
And the 3rd transformer may well have failed due to improper
wiring, or
a loose connection leading to excessive current leading to insulation
breakdown and a hard short, or as has been suggested repeatedly, a
fault
somewhere on the secondary side.
You've also agreed that there are wire color discrepancies and several
respondents have opined that both halves of the primary should,
perhaps,
have been wired in parallel to accommodate the current requirements.
I brought the old transformer to a local HVAC supply house, and the
sales
person (whom I perceived to be at least somewhat of an expert), gave
me the
third transformer as a suitable replacment. I chose to connect the
transformer
according to the instructions, and not according to any speculation
"opined" in
this group.
So, I too am curious, have you acquired some appropriate fuses,
figured
out how to monitor the current, and been able to schedule some time
off
from your other responsibilities so that you can actually work through
this puzzle once the new xformer arrives? Are you equipped to bench
test
the new transformer to verify wiring color scheme before you
install it?
Do you know how to test that bridge rectifier? Seems like you have a
*lot* you could be doing while waiting for the UPS guy.
I'm sorry you feel that I'm not "doing" anything or that I'm leaving
you
hanging, but I'll be making the repairs on my own schedule, as time
permits.
My own place of employ has me working 12 and 16 hour days, so I
can't be
everywhere at once. Plus, the weather here is pleasant and there's
been no
real need to run the air conditioner, and the house has two A/C
units anyway so
I'm in no hurry. I don't have the fuses or fuse holders yet, but the
transformer isn't going in without them, so it will be taken care
of. My
common sense tells me that I really shouldn't *have* to test and
verify the
living daylights out of a new transformer, but I will most certainly
get
bitched out here if I don't, so yes, that will be done. I don't
really recall
the discussion about the bridge rectifier, but I'll look for it. I
will be
reviewing the entire discussion and make a checklist of all the
steps I need to
perform.
Anything else?- Hide quoted text -
- Show quoted text -
After you put it in, measure the current and voltages in both
the primary and secondary. I'd measure them both with the
AC running and with it not running.
Also, not sure if anyone ever covered this, but when the transformers
have failed have they all been in cooling mode, heating, or both?
Yep, I'll do that. It's only in cooling mode that the transformers
have failed, but I'm in Texas and we're long past the point where
we'll be needing the heater for a while, so it's hard to say whether
or not running the heat would also trigger the problem.
Steve, As said before the best thing to do is to fuse both the primary
and secondary windings.
If you have the recommended (original) transformer ratings handy that
should make it easy to figure out. For example, if the secondary (24VAC
as I recall) is rated at 1A, then the primary fuse is 1/5 of that
(24:120 - plus a fudge factor) suggesting that a 0.25A slo-blo should
last fairly well, and a 1A slo-blo on the secondary winding. If the
secondary is rated at 2A, then I'd go with a 0.5A slo-blo on the
primary, along with a 2A slo-blo on the secondary.
Two fuse holders should be fine - one for the 120VAC side and one for
the 24VAC side.
Hope this helps - at least it will reduce the cost of replacing
transformers!
John :-#)#
Hi,
Giving up for real solution? Just band aid fix? VChanging blown x-former
to blown fuse? If I am having problem like that I'd fix it for sure
dragging out all the tools I need. O'scope, clamp ammeter, DVM, etc.
Maybe it is asked already but is happening all of sudden or been like
that since the system got installed? Every symptom has cause.
The fuse is not being put forward as a solution - just to avoid
The fuse is not being put forward as a solution - just to avoid
blowing the transformer while finding the real problem.
Rgwew i a such thing as current limiting x-formers. One thig I'd tryclare@snyder.on.ca
The fuse is not being put forward as a solution - just to avoid
blowing the transformer while finding the real problem.
** The fuse will actually help you diagnose the problem.
If the fuse opens soon as AC power is applied - the tranny is being
overloaded.
If the fuse opens after some time because insulation in the primary side has
failed, replacement fuses will open immediately despite the secondary being
disconnected.
...Phil
Hmm,
This isunthinkab;e crazy idea but is the x-former being put in backward?