Crompton Controls DCM User Manual
Page 18
Emotron AB 01-2120-01r2
Installation
17
For larger motors (rated current > 100 A), use two current transformers - one
outer, standard transformer, and one CTM010 with two windings. Table 2
shows the choice of transformers (standard + CTM010) and number of wind-
ings for currents exceeding 100 A.
The following examples illustrate the choice of current transformer(s):
Example A. Pump motor has a rated current of 6.9 A. According to Table 1,
choose CTM010 with one (1) winding.
Example B. Pump motor has a rated current of 108 A. According to Table 2,
choose a standard current transformer 150:5 with one (1) winding and a
CTM010 with two (2) windings.
In order to ensure accurate calibration of the Emotron DCM, it is essential that
you use the correct CTM (and, additionally, a standard current transformer)
and apply the exact number of wirings in accordance with the tables above.
Table 2
Table for selection of current transformers for motors with a rated current
greater than 100 A
Rated motor current
Current transformers
Number of windings
101 to 150 A
150:5 +
CTM010
1 +
2
151 to 250 A
250:5 + CTM010
1 +
2
251 to 500 A
500:5 + CTM010
1 +
2
501 to 999 A
1000:5 + CTM010
1
+ 2
NOTE: The current transformer must be linked to the phase connected to
terminal 9 (L1).