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460v to 24v transformer tripping

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#2 ·
could be many things but I would start looking for a short in wire somewhere. Had one similar where a valve would open in a pharmaceutical plant and move the 24v and it happened to have a rip on the wire and it would trip. Took forever to find this out as the damn valve that would move was only opened and closed for a short period of time.
 
#3 ·
the first thing you look at is the max fused/breaker size on unit and see if it has the correct one in. then start looking at the motors see if they are over amping then see any loose connections.. start eliminating components!
 
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#4 ·
wika_boy said:
The 460v to 24v 4amp transformer overload keeps tripping about every 4 hours. Unit is a dx system. Any ideas why. Thanks
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akelesis said:
the first thing you look at is the max fused/breaker size on unit and see if it has the correct one in. then start looking at the motors see if they are over amping then see any loose connections.. start eliminating components!
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Akelesis, did you read his post carefully? He said the 4 amp transformer overload keeps tripping. That overload is in the 24V circuit. What would the breaker or the motor in the 460V circuit have to do with that?

Wika_boy, are you a DIY. An HVAC tech would know how to diagnose that.
 
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#5 ·
wika_boy said:
The 460v to 24v 4amp transformer overload keeps tripping about every 4 hours. Unit is a dx system. Any ideas why. Thanks
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New transformer?

Correct tap?

Measured load on secondary?
 
#6 ·
once you verify correct voltage on the primary side of your xfmr id check the loads like already mentioned. you could ohm each holding coil but depending on size of system & amount of components it might take a while but it beats repeat trips to location
 
#7 ·
Measure the amp draw on the 24 volt side as the unit runs, somethings coil could be overheating then shorting or the amp draw is close to the breaker trip point that it takes that long to heat up and trip. Had an unloader coil do that a while back, unit would run a good 30 minutes.
 
#8 ·
hvac69 said:
Measure the amp draw on the 24 volt side as the unit runs, somethings coil could be overheating then shorting or the amp draw is close to the breaker trip point that it takes that long to heat up and trip. Had an unloader coil do that a while back, unit would run a good 30 minutes.
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I've run in to the same situation with run contactors. Thank you NAFTA!:gah:
 
#9 ·
Akelesis, did you read his post carefully? He said the 4 amp transformer overload keeps tripping. That overload is in the 24V circuit. What would the breaker or the motor in the 460V circuit have to do with that?

Wika_boy, are you a DIY. An HVAC tech would know how to diagnose that.

sorry buddy. i misread the thread. i was too quick to respond. sorry guys i do look like an idiot now
 
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#11 ·
Check the time delay. I have seen time delays do this several times.
 
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#14 ·
#15 ·
Stick your amp probe on 24v side to see the draw at restart then you can watch the load grow towards overload. You can also put the probe on different component coils and see the individual draw. If the power side is in series you use temp wire direct from trans to each component coil to isolate the draw from each. Having chased this ghost before I even found it hiding in a normally closed high limit that built more resistance the longer it was energized.
 
#16 ·
Hi guys, it's bklyntek, same thing has happened turned out it was the cf motor on the 2nd stage ck. On a air cool chiller. Moderate temps. Kept me from diagnosing it faster. At the time, I had removed the 3.2amp from an old decommissioned carrier rtu & used it to isolate the coil problem. Now, It's part of my tool bag, don't have to stock up on the small glass fuses in my truck. It's worth having with you. Hope this helps out.
 
#17 ·
Bklyntek said:
Hi guys, it's bklyntek, same thing has happened turned out it was the cf motor on the 2nd stage ck. On a air cool chiller. Moderate temps. Kept me from diagnosing it faster. At the time, I had removed the 3.2amp from an old decommissioned carrier rtu & used it to isolate the coil problem. Now, It's part of my tool bag, don't have to stock up on the small glass fuses in my truck. It's worth having with you. Hope this helps out.
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You mean it was in the control circuit for the CF motor, right?
 
#18 ·
If this is a rooftop with an economizer, there is always the possibility of a short in the circuits going through econo wiring/modules.
 
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#19 ·
Let me explain,in fl. we can have power swings up/dn in excess of 10-15%,(summer). So as a precaution I would add TDR relay's(var.10min.) and adjust times to protect all my loads. Also,served to stage eqpt.in (1-2m.)increments. Because of the added TDR's, 45'-60' mornings that year,left it lurking in the background. There is a method behind the madness, I hope that explains it. Take care guys, bklyntek.
 
#20 ·
Sorry "time builder",I can be alittle long winded in my answers sometimes, but yes it was in the control circuit for 2nd stage condenser fan bank. just read where I wrote "cf motor", my mistake. Thanks for calling my attention to that, proper terminology is a must.
I will be more careful in the future.
 
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