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Topic Title: "Split winding" motors
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Created On: 24 January 2011 04:52 PM
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 24 January 2011 04:52 PM
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handlewithcare

Posts: 9
Joined: 02 September 2010

Hi all

I am currently working on installing pfc/ monitoring energy efficiency in industrial buildings. Previous employees in my firm have fitted a chiller unit with some local pfc on the compressors. Looking at the schematic for the chiller, it shows a 3 lines separating after the circuit protection for each compressor and going to 2 contactors, ie 3 phases to each. From each contactor, there are 3 phases to each winding in each compressor shown marked (UVW) and (ZXY).

In the abscence of further information, I'd like to know what the arrangement is and what it's designed to achieve, as I think the installers may have incorrectly fitted the pfc, whereby its only applied to one winding per compressor. The schematic does not show or elaborate on what or how the contactors for each compressor are controlled, hence my trepidation with this.

Enlightenment appreciated........
 24 January 2011 09:58 PM
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slittle

Posts: 3510
Joined: 22 November 2007

This might be better posted in the wiring regs forum.

Are the contactors interlocked or not ??. If interlocked I'd suspect star delta, if not then as you've already suggested split phase

Stu
 28 January 2011 12:30 PM
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Jaymack

Posts: 4639
Joined: 07 April 2004

Originally posted by: handlewithcare
Previous employees in my firm have fitted a chiller unit with some local pfc on the compressors.

Is PFC actually present and how is it connected?

Looking at the schematic for the chiller, it shows a 3 lines separating after the circuit protection for each compressor and going to 2 contactors, ie 3 phases to each. From each contactor, there are 3 phases to each winding in each compressor shown marked (UVW) and (ZXY).

Almost certainly, this is star delta operation for 3 phase operation to larger kW ratings of motors.

Regards
 28 January 2011 03:30 PM
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kalookicedogs

Posts: 181
Joined: 23 October 2008

Originally posted by: slittle

This might be better posted in the wiring regs forum.



Are the contactors interlocked or not ??. If interlocked I'd suspect star delta, if not then as you've already suggested split phase



Stu


You would have three contactors for star/delta

-------------------------
My ex wife was an amazing house keeper. Problem is I never got the damn thing back.
 28 January 2011 03:32 PM
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kalookicedogs

Posts: 181
Joined: 23 October 2008

Originally posted by: Jaymack

Originally posted by: handlewithcare

Previous employees in my firm have fitted a chiller unit with some local pfc on the compressors.


Is PFC actually present and how is it connected?



Looking at the schematic for the chiller, it shows a 3 lines separating after the circuit protection for each compressor and going to 2 contactors, ie 3 phases to each. From each contactor, there are 3 phases to each winding in each compressor shown marked (UVW) and (ZXY).


Almost certainly, this is star delta operation for 3 phase operation to larger kW ratings of motors.



Regards


Possibly dual wound 2 speed motor?? More information would be useful. What does the com[pressor / motor data plate say.?

-------------------------
My ex wife was an amazing house keeper. Problem is I never got the damn thing back.
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