UPS for freezer?

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JES2727

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A commercial refrigerator/freezer in a lab does not always start up again after brown-outs or power failures. Apparently the control package is a bit sensitive. As a short term solution they have asked me to provide & install a UPS. They think that the same type of UPS they plug their desktop computers into will work for this. I'm not so sure. The RLA is 8.8, but the LRA is 72. Can anyone recommend a UPS or PDU that is suitable for this application?
Thanks.
 
I would think a UPS sized for the 8.8 A would be fine. You're just trying to ride out a very brief brownout, not power the freezer for any length of time. The only way you would have any problem would be if the compressor was off and tried to start during the brownout while being powered by the UPS. What are the odds of that?
 
JES2727 said:
A commercial refrigerator/freezer in a lab does not always start up again after brown-outs or power failures. Apparently the control package is a bit sensitive. As a short term solution they have asked me to provide & install a UPS. They think that the same type of UPS they plug their desktop computers into will work for this. I'm not so sure. The RLA is 8.8, but the LRA is 72. Can anyone recommend a UPS or PDU that is suitable for this application?
Thanks.
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Check the inrush rating (amplitude and duration) of the UPS to be sure it will power up on battery. A compressor load is way different than a computer load.
 
i would only use a true sinewave UPS....the cheaper square wave ones could wreak havoc on your fridge. I would also find out from the UPS mfgr about putting a motor on it, UPS might not like that much inductive load.
 
JES2727 said:
A commercial refrigerator/freezer in a lab does not always start up again after brown-outs or power failures. Apparently the control package is a bit sensitive. As a short term solution they have asked me to provide & install a UPS. They think that the same type of UPS they plug their desktop computers into will work for this. I'm not so sure. The RLA is 8.8, but the LRA is 72. Can anyone recommend a UPS or PDU that is suitable for this application?
Thanks.
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I would investigate the issue with the freezer. A UPS for 72A would rather be pricey. The LRA would still not tell you what the spike would be at startup, that nasty little bugger can throw your static switch and you would be back in the 'no-start' business. If the freezer is so critical then they should have a redundant chiller unnit to begin with.

UPS is not a correct solution to this dilemma, except if I were to sell it.:grin:
 
weressl said:
UPS is not a correct solution to this dilemma, except if I were to sell it.:grin:
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dereckbc said:
UPS is not the ANSWER
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Agreed. This is their short term solution. If I can find a UPS that can handle the load and doesn't cost as much as a new freezer, I'll be happy to sell it to them.
 
I would find a way to isolate the controls and put them on a small UPS. A freezer can last a few days if you had a total utility failure.
It seems to me like you just want to ride through a short outage if you are looking at a UPS
 
UPS, common trade short hand for "Uninterruptible Power Supply" typically a battery back up unit but there are other types like flywheel type.
 
jrannis said:
I would find a way to isolate the controls and put them on a small UPS. A freezer can last a few days if you had a total utility failure.
It seems to me like you just want to ride through a short outage if you are looking at a UPS
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Bingo. We're starting to do this with equipment because we've had enough of a problem in the past with controls not coming up after a dip or outage. When buying new equipment many manufacturers will omit the typical control power transformer and wire the controls to a terminal block for us to connect UPS power to onsite.
 
jrannis said:
A freezer can last a few days if you had a total utility failure.
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Had a emergency call at a residential condo, the main service melted down> restoration of power was going to take a while, several people kept asking us about their refrigerators and freezers losing food. I told them not my issue BUT leave the door shut stay out of there, the units should be OK for a while. One lady kept coming back and telling us he stuff was melting "Everytime I look in the freezer some to be thawing" DO YOU LISTEN?
 
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