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%
Industrial Control Transformers
Type T Transformers
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.
Regulation Chart for Type T
|
|
| Secondary Voltage |
|
| |
|
|
|
| |||
VA | 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 |
|
|
|
|
|
|
|
5
08/2005 |
|
|
| © |
