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FreezerGeezer
28-05-2004, 11:30 AM
Hi guys

I've looked on Copeland's website, and on ours, and I cannot find a smal but vital bit of info, so I'm hoping someone here knows:
What is the switching resistance for the winding overheat sensor on Copeland ZR11M3E-TWD compressors, please?

chemi-cool
28-05-2004, 12:18 PM
I think its only teperature related.

those sensors are usualy bimetal.

why is this info so vital?

chemi

FreezerGeezer
29-05-2004, 03:48 PM
Hello Chemi

Our factory came up with the answer for me. Yes, they are temperature related. Apparently in these Copelands there are 4 thermisors in series around the windings. There's an external klixon (like Bitzer recips) that reads the resistance & stops the compressor if it's getting too hot.
The reason that I needed to know was that a customer had problems with one unit that refused to work. He didn't sound like he really trusted his tech's to have done the diagnostics properly, and wanted to know this info as he felt that the sensing system may be faulty.
It's often amazing how much information people expect you to have at your fingertips when you do tech. support - never mind if your factory is using bought in bits (as they all do, of course)! :D

chemi-cool
29-05-2004, 04:05 PM
it easy to check it.

just test for continuity between the points S1 and S2.
by the way, this information is available in the copeland catalog, form 97-49 R2 and its 5 termistors.

but as you said, you can never guess what info the customer an request.

chemi

Peter_1
30-05-2004, 12:11 PM
Just read this thread,

If you still need the curve of the 4 thermistors in serie, I can scan the schematic.
There is one thermistor for each phase with a nominal response temperature of 80°C for protection of a blocked rotor, mounted in the upper(suction gas) side of the compressor motor.

A fourth thermistor with nominal response temperature of 140°C is located in a winding head at the lower end of the motor.

A fifth sensor is located in the discharge port to control discharge superheat.

This entire chain (no contacts but a ohms resistance) is then connected to S1/S2 of the special Kriwan (69SC)

Use max 3V for resistance check. Resistance must be 1250 ohms or lower if motor is cold.

Functional check, disconnect S1/S2 and start up motor --> motor should not start.

FreezerGeezer
02-06-2004, 08:25 AM
Hello Peter, Chemi

Thanks for the input. Chemi, I had a look on Copeland's web catalogue, and couldn't find this info there. Maybe it's buried elsewhere on their site. :(

I'll try to attach a copy of the document the factory gave me in the next day or 2. If I understand the attachment system right, it will perform as a link to my PC - can't see our IT dept. appreciating that (:D) , so I'll have to do it from home.

chemi-cool
03-06-2004, 08:34 PM
hi freezergeezer,

copeland headquarters are in Belgium, I think the best way to obtain all the nececary information is to get in touch with them.

about two months ago I attended a seminar about all the latest in copland compressors and the lecturer was an english man with funny accent that works in Belgium.
you can email them at ecommerce@ecopeland.com
also their software is worth downloading.

chemi