RTHB - Momentary Power Loss

[forservice]

I have been ask to resolve a Momentary Power Loss issue with a RTHB Chiller with a WYE starter. This condition accurs just after transition. Previous techs have replaced auxillary contacts, one CT and the starter module. All starter test were performed and passed. CT tests were performed and one CT replaced due to a low Ohm condition and the new replacement CT read the same as the one it replaced. CTs produce acurate readings during chiller operation. Operation of the HPC verified. Incoming power was found to be normal through out startup with a DMM. (several actually) Chiller starts and runs fine with this condition is disabled. Is it possible to see the required 2.5 cycles of loss with a standard DMM? Any suggestions?

[absrbrtek]

No, youll need an osiliscope to see this happen.

[chillrdude]

I have seen this quite a few times, the only thing I would suggest that hasnt been done yet according to your post would be to go ahead and replace the HPC, not sure how "the operation of the HPC was verified". I have seen them cause some problems in the past especially with the design and location of the HPC, it really takes a beating on the discharge pipe with harmonics. I think I only have acouple of these machines out there with the momentary power loss feature turned off.

I never really got worked up enough about it to put a scope on it, I would be curious to what you find if you did.

Good luck

[ZeroCool]

I don't know if that unit uses that piece of s**t OPTI input for failure in the starter mod. If it does, thats probably your problem, has been mine on a few cv's.

[turbovac]

we were having problems with starter modules & trips, istall
a homemade damper using 6 turns of 1/4 copper pipe & have
had no problems since

[lord of the screws]

I think chillerdude is right on I have seen it a few times if you look at the HPC on the print you will see how it can cause the problems you are seeing.

[forservice]

Problem resolved. Found that 2T2 transformer had also been replaced. OEM replacement was not marked as to phasing - swapped leads and no more shutdowns. Thanks for your input guys.