using small Bitzer( Motor2) for MT application

[herman]

<link rel="File-List" href="file:///C:%5CUsers%5CMihai%5CAppData%5CLocal%5CTemp%5Cmsohtml1%5C01%5Cclip_filelist.xml"><o:smarttagtype namespaceuri="urn:schemas-microsoft-com<img src=" http:="" www.refrigeration-engineer.com="" forums="" images="" smilies="" redface.png="" border="0" alt="" title="Embarrassment" smilieid="3" class="inlineimg"></o:smarttagtype> Dear friends,



As you know Bitzer compressors has two motors for each compressor.<o></o>
By eg. 6H-35.2Y motor 35 HP <st1:stockticker>AND</st1:stockticker> 6h-25.2Y.<o></o>
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The ranges is similary between evaporating -10 and -40 C and condensing 35-50 C temperature R 404A.<o></o>
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My question is:<o></o>
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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.<o></o>
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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.<o></o>
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Even this I’ve seen other big companies like LINDE, especially, uses only small motors for Bitzer compressors?<o></o>
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Is there any trick?<o></o>
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Your experience could help me.<o></o>

[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.