230 V electrical problems 1

[jimmylovesni]

We have 3to 4 different pieces of equipment running on 230V lines in our building that have got damaged in the last month (all are -80C freezers. Some of the freezers are brand new.

What is the best way to analyze the power? I have a 1000X voltage probe and a few Oscopes and was thinking of taking some FFTs and looking at 60Hz signal (time domain) as well. Does this seem logical?

thanks
Jim

 

[jimmylovesni]

it looks like the freezer is 208 and plugged into 208. It can run on either 230 or 208 though.

Im guessing our maintaince people are going to be montioring it, as from the last post. They installed a power monitors. The also had a general power montior that recorded some power flucations that day we had problems.

if anyones instrested, this is what these types of freezers look like

http://www.thermoscientific.com/wps/portal/ts/products/catalog?navigationId=L10487&categoryId=80523

I really think im alll set with this at this point unless someone can recommed some type of UPC for 208

 

[waross]

Thanks for the update.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[waross]

A side question, jimmylovesni, at minus 80 C do you get any Carbon dioxide snow forming in the coolers from the air?


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

jimmylovesni; I wanted to point out one other thing. Virtually none of those are really 208V. We've never seen one that didn't die prematurely when run on 208V.
The machine's name plate will say 208-230 but that's

!.
If you actually look at the plate on the compressor it will say something like 200V/50Hz 230V/60Hz.

The only way to make these things reliable is to use boost transformers to get the voltage up to 230V.

Keep in mind that the single phase units have a lot more failures than the three phase units because of all the starting junk needed, and the very high starting duty cycles these deeep freezes need.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Hi Keith. 10 years ago I would have agreed with you. However I am coming across more and more motors rated for either 200-230 Volts 60 Hz or 208-230 Volts at 60 Hz.
A quick check of Grainger.com shows some farm duty motors rated for 200-230 Volts 60 Hz and some at 208-230 Volts. I assume that these are basically 230 Volt motors that are slightly oversized so as to be able to deliver full HP at the reduced voltage.
I have also been seeing 200-230 Volt rated hermetic compressors in the field.
We've known each other long enough that you know that I know the difference between 50Hz and 60Hz. Grin
Yours
Bill

Bill
--------------------
"Why not the best?"
Jimmy Carter