Filter
Top Products
Industrial Control Transformers
Type T Transformers
5
08/2005
© 1999–2005 Schneider Electric All Rights Reserved
Selection Guide
1. Determine inrush and sealed VA of each coil in the control circuit and VA
of all other components.
2. Total all sealed VA of all operating coils and other loads VA (determines
minimal VA size required for the circuit).
3. Total the inrush VA of all coils that are starting at the same time and all
loads and coils that are running (using the regulation chart to give
possible units to be used).
4. Take VA size from step 2, go to standard VA size in chart below. Make
sure inrush VA from chart is greater than total VA from step 3. If not, go
to next larger VA size and repeat.
If your supply voltage is stable and fluctuates less than 5%, we recommend
you use the 90% secondary voltage column. If your supply voltage is not
stable and fluctuates more than 10%, we recommend you use the 95%
secondary voltage column. We recommend that you never use the 85%
secondary voltage column since magnetic devices lose life expectancy if
they are continuously started at 85% of rated voltage.
Example:
This example assumes the following:
• Two NEMA size 0 contactors do not start together, but one
could be ON when the other starts.
• One NEMA size 2 contactor can start with either of the
other contactors.
• One pilot light at 2 VA
1. VA and inrush are:
NEMA 0: sealed 27 VA; inrush 245 VA
NEMA 2: sealed 37 VA; inrush 311 VA; pilot light 2 VA
2. Total VA: 27 + 27 + 37 + 2 = 93 VA
3. Total inrush VA: 245 + 311 + 27 + 2 = 582 VA
4. From Regulation Chart for Type T at right below:
100 VA minimum unit; inrush 499 VA will not work at 90%
150 VA (next standard size); inrush 666 VA will work at 95%
Regulation Chart for Type T
VA
Secondary Voltage
Inrush UL VA at 20% Power Factor Inrush UL VA at 40% Power Factor
95% 90% 85% 95% 90% 85%
50 193 266 339 151 215 282
75 271 396 520 210 318 430
100 339 499 659 266 404 549
150 666 893 1120 529 731 942
200 588 815 1041 459 659 866
250 1416 1910 2388 1057 1494 1936
300 1634 2184 2709 1194 1681 2169
350 1894 2592 3261 1392 2005 2621
500 3197 4104 4981 2374 3195 4019
750 3770 5515 7231 2887 4391 5945
1000 6587 9079 11430 4706 6886 9051
1500 19324 23983 28607 15066 19361 23756
2000 31384 38777 46161 24794 31630 38667
3000 26539 39934 52713 19355 30721 42216
5000 53111 85265 116277 39368 66309 93882