Trane CVRD Installation Manual page 24

PART-SVN82C-EN
Appendix C
See Table C4 to select CT Rating and resulting CT meter scale. In many cases more
than one selection is possible.
Table C4. Current transformer data for single stage CT per phase
Actual motor
RLA (Amps) Part number
5.6 - 8.3 TRR00979 or TRR01272
6.7 - 10.0 TRR00979 or TRR01272
8.4 - 12.5 TRR00979 or TRR01272
11.2 - 16.6 TRR00979 or TRR01272
16.7 - 25.0 TRR00979 or TRR01272
25.0 - 37.5 TRR00958
33.4 - 50 TRR00979 or TRR01272
50 - 75 TRR00958
67 - 100 TRR00714
100 - 150 TRR00715
134 - 200 TRR00716
184 - 275 TRR00717
267 - 400 TRR00718
334 - 500 TRR00982 or TRR01142
467 - 700 TRR00981 or TRR01255
667 - 1000 TRR00980 or TRR01405
934 - 1400 TRR01571 or TRR01579
1200 – 1800 TRR01572 or TRR01580
Method 2. Dual stage CT calculations, for greater than 600 Vac
Motor current sensing using the two CT per phase arrangement. In this case two
CT's are used per phase to either achieve the necessary turn-down or for metering
convenience. The first stage consists of either the X13580047 or X13580048 CT
(each of these CT's have a 5 amp secondary). The second stage consists of the
X13580266-01 CT (takes 3.6 amps down to 100 ma).
CT Meter Scale = CT Rating / (Number of Primary Turns x 1.3889)
CT Meter Scales with decimals need to be truncated as appropriate so that the
measured motor amps is less than the actual motor amps.
In this case the CT Rating should be picked to be in the range of 100% to 150% of
Actual Motor RLA x Number of Primary Turns x 1.3889. See Table C5 to select CT
Rating and resulting CT meter scale. In many cases more than one selection is
possible.
CT ratio CT rating
Ext. (Amps:Amps) (Amps)
-09 50:0.1 50
-09 50:0.1 50
-09 50:0.1 50
-09 50:0.1 50
-09 50:0.1 50
-10 75:0.1 75
-09 50:0.1 50
-10 75:0.1 75
-01 100:0.1 100
-02 150:0.1 150
-03 200:0.1 200
-04 275:0.1 275
-05 400:0.1 400
-06 500:0.1 500
-07 700:0.1 700
-08 1000:0.1 1000
-11 1400:0.1 1400
-12 1800:0.1 1800
Primary CT meter
turns scale
6 8.3
5 10.0
4 12.5
3 16.6
2 25
2 37.5
1 50
1 75
1 100
1 150
1 200
1 275
1 400
1 500
1 700
1 1000
1 1400
1 1800
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