using small Bitzer( Motor2) for MT application

[herman]

Dear friends,



As you know Bitzer compressors has two motors for each compressor.
By eg. 6H-35.2Y motor 35 HP AND 6h-25.2Y.

The ranges is similary between evaporating -10 and -40 C and condensing 35-50 C temperature R 404A.

My question is:

Could I use the smaller motor (25 HP)? The application is an room ready to work also 0C and -18C of course using EXV Alco or Danfoss.

Theroretically , in heavy working conditions for this compressor to/tk: -5/+50C, if accidentally gets, the pressure is big enough to burn out my motor.

Even this I’ve seen other big companies like LINDE, especially, uses only small motors for Bitzer compressors?

Is there any trick?

Your experience could help me.

[mrfrze]

1) The dividing line between LT & MT, or in your case Motor 1 & 2 (on avg.) is a ~(-5C) +23f - the caveat is that it depends on your SCT and Refrigerant.
2) Download the Bitzer Software (for free) and run it....it CLEARLY spells it out for you.

[Magoo]

The trick is using crankcase pressure regulators to limit the current draw during pull down and after defrost loads. Recommend checking the free software as mentioned in earlier post/ reply by Mr Freeze.
Using MOP expansion valves can also reduce compressor loading.