Medium Voltage Transformer Selection Guide
TEMCo Medium Voltage Isolation Transformers are designed for stepping down incoming higher voltage power to utilize voltages for commercial, institutional, or industrial applications. The NEMA 3R ventilated enclosure makes it suitable for indoor use as well as outdoor protection against rain and sleet. Our transformers are built to last, guaranteed. That's why we back these with a decade long warranty.
Features
• 1 or 3 Phase
• Copper or Aluminum Wound
• 60 Hz
• NEMA 3R
• 150°C rise
• UL Listed and CSA Certified
• 10 Year Warranty
How to Select a Transformer
Selecting the right voltage transformer is simple. Review the following considerations to determine the best fit for your application. Then, select a transformer from one of the tables below.
Input Voltage
Select a transformer that will operate on the supply voltage available at your facility (Example: 2400V, 4160V, or 7200V). To ensure compatibility, check the wiring diagram by clicking a part number and viewing its product page.
Frequency
All of TEMCo's medium voltage transformers are rated for 60 Hz.
Windings
Copper wound models cost more than the equivalent aluminum wound versions. The primary advantage of copper is its superior corrosion resistance. Copper wound transformers are commonly used for corrosive or high humidity environments like marine applications, and when cost is not a factor.
kVA or Amp Output
Select a transformer with kVA based on your load requirements. It is fine to oversize significantly, but never to undersize for your load. For motor loads, do not exceed 60% of the maximum capacity of the transformer, because electric motors have start up requirements significantly higher than their running requirements.
Product Selection
Below is a list of our full line of medium voltage transformer configurations we offer. First, find the primary voltage you need. Then, click on the primary voltage you need to view the full product selection of secondary voltage configurations.
Transformer sizes offered from 15 to 333 kVA single phase and 15 to 750 kVA three phase.
1 Phase
| A. 2400V Primary | ||||||
| kVA | Aluminum | Copper | ||||
| 600V Sec | 480/240V Sec | 240/120Sec | 600V Sec | 480/240V Sec | 240/120Sec | |
| 15 | T57509 | T57519 | T57529 | T38340 | T38350 | T38360 |
| 25 | T57510 | T57520 | T57530 | T38341 | T38351 | T38361 |
| 37.5 | T57511 | T57521 | T57531 | T38342 | T38352 | T38362 |
| 50 | T57512 | T57522 | T57532 | T38343 | T38353 | T38363 |
| 75 | T57513 | T57523 | T57533 | T38344 | T38354 | T38364 |
| 100 | T57514 | T57524 | T57534 | T38345 | T38355 | T38365 |
| 150 | T57515 | T57525 | T57535 | T38346 | T38356 | T38366 |
| 167 | T57516 | T57526 | T57536 | T38347 | T38357 | T38367 |
| 250 | T57517 | T57527 | T57537 | T38348 | T38358 | T38368 |
| 333 | T57518 | T57528 | T57538 | T38349 | T38359 | T38369 |
| B. 4160V Primary | ||||||
| kVA | Aluminum | Copper | ||||
| 600V Sec | 480/240V Sec | 240/120Sec | 600V Sec | 480/240V Sec | 240/120Sec | |
| 15 | T57539 | T57549 | T57559 | T38370 | T38380 | T38390 |
| 25 | T57540 | T57550 | T57560 | T38371 | T38381 | T38391 |
| 37.5 | T57541 | T57551 | T57561 | T38372 | T38382 | T38392 |
| 50 | T57542 | T57552 | T57562 | T38373 | T38383 | T38393 |
| 75 | T57543 | T57553 | T57563 | T38374 | T38384 | T38394 |
| 100 | T57544 | T57554 | T57564 | T38375 | T38385 | T38395 |
| 150 | T57545 | T57555 | T57565 | T38376 | T38386 | T38396 |
| 167 | T57546 | T57556 | T57566 | T38377 | T38387 | T38397 |
| 250 | T57547 | T57557 | T57567 | T38378 | T38388 | T38398 |
| 333 | T57548 | T57558 | T57568 | T38379 | T38389 | T38399 |
| C. 7200V Primary | ||||||
| kVA | Aluminum | Copper | ||||
| 600V Sec | 480/240V Sec | 240/120Sec | 600V Sec | 480/240V Sec | 240/120Sec | |
| 15 | T57569 | T57579 | T57589 | T38400 | T38410 | T38420 |
| 25 | T57570 | T57580 | T57590 | T38401 | T38411 | T38421 |
| 37.5 | T57571 | T57581 | T57591 | T38402 | T38412 | T38422 |
| 50 | T57572 | T57582 | T57592 | T38403 | T38413 | T38423 |
| 75 | T57573 | T57583 | T57593 | T38404 | T38414 | T38424 |
| 100 | T57574 | T57584 | T57594 | T38405 | T38415 | T38425 |
| 150 | T57575 | T57585 | T57595 | T38406 | T38416 | T38426 |
| 167 | T57576 | T57586 | T57596 | T38407 | T38417 | T38427 |
| 250 | T57577 | T57587 | T57597 | T38408 | T38418 | T38428 |
| 333 | T57578 | T57588 | T57598 | T38409 | T38419 | T38429 |
| D. 12.47 kV Primary | ||||||
| kVA | Aluminum | Copper | ||||
| 600V Sec | 480/240V Sec | 240/120Sec | 600V Sec | 480/240V Sec | 240/120Sec | |
| 15 | T57599 | T57609 | T57619 | T38430 | T38440 | T38450 |
| 25 | T57600 | T57610 | T57620 | T38431 | T38441 | T38451 |
| 37.5 | T57601 | T57611 | T57621 | T38432 | T38442 | T38452 |
| 50 | T57602 | T57612 | T57622 | T38433 | T38443 | T38453 |
| 75 | T57603 | T57613 | T57623 | T38434 | T38444 | T38454 |
| 100 | T57604 | T57614 | T57624 | T38435 | T38445 | T38455 |
| 150 | T57605 | T57615 | T57625 | T38436 | T38446 | T38456 |
| 167 | T57606 | T57616 | T57626 | T38437 | T38447 | T38457 |
| 250 | T57607 | T57617 | T57627 | T38438 | T38448 | T38458 |
| 333 | T57608 | T57618 | T57628 | T38439 | T38449 | T38459 |
3 Phase
| A. 2400V Primary | ||||||||
| kVA | 600Y/347 V Sec | 480Y/277 V Sec | 240V Delta Sec | 208Y/120 V Sec | ||||
| Aluminum | Copper | Aluminum | Copper | Aluminum | Copper | Aluminum | Copper | |
| 15 | - | T38460 | - | T38470 | - | T38480 | - | T38490 |
| 30 | - | T38461 | - | T38471 | - | T38481 | - | T38491 |
| 45 | - | T38462 | - | T38472 | - | T38482 | - | T38492 |
| 75 | - | T38463 | - | T38473 | - | T38483 | - | T38493 |
| 112.5 | T38280 | T38464 | T38286 | T38474 | T38292 | T38484 | T38298 | T38494 |
| 150 | T38281 | T38465 | T38287 | T38475 | T38293 | T38485 | T38299 | T38495 |
| 225 | T38282 | T38466 | T38288 | T38476 | T38294 | T38486 | T38300 | T38496 |
| 300 | T38283 | T38467 | T38289 | T38477 | T38295 | T38487 | T38301 | T38497 |
| 500 | T38284 | T38468 | T38290 | T38478 | T38296 | T38488 | T38302 | T38498 |
| 750 | T38285 | T38469 | T38291 | T38479 | T38297 | T38489 | T38303 | T38499 |
| B. 4160V Primary | ||||||||
| kVA | 600Y/347 V Sec | 480Y/277 V Sec | 240V Delta Sec | 208Y/120 V Sec | ||||
| Aluminum | Copper | Aluminum | Copper | Aluminum | Copper | Aluminum | Copper | |
| 15 | - | T38500 | - | T38510 | - | T38520 | - | T38530 |
| 30 | - | T38501 | - | T38511 | - | T38521 | - | T38531 |
| 45 | - | T38502 | - | T38512 | - | T38522 | - | T38532 |
| 75 | - | T38503 | - | T38513 | - | T38523 | - | T38533 |
| 112.5 | T38304 | T38504 | T38310 | T38514 | T38316 | T38524 | T38322 | T38534 |
| 150 | T38305 | T38505 | T38311 | T38515 | T38317 | T38525 | T38323 | T38535 |
| 225 | T38306 | T38506 | T38312 | T38516 | T38318 | T38526 | T38324 | T38536 |
| 300 | T38307 | T38507 | T38313 | T38517 | T38319 | T38527 | T38325 | T38537 |
| 500 | T38308 | T38508 | T38314 | T38518 | T38320 | T38528 | T38326 | T38538 |
| 750 | T38309 | T38509 | T38315 | T38519 | T38321 | T38529 | T38327 | T38539 |
| C. 7200V Primary | ||||||||
| kVA | 600Y/347 V Sec | 480Y/277 V Sec | 240V Delta Sec | 208Y/120 V Sec | ||||
| Aluminum | Copper | Aluminum | Copper | Aluminum | Copper | Aluminum | Copper | |
| 15 | - | T38540 | - | T38550 | - | T38560 | - | T38570 |
| 30 | - | T38541 | - | T38551 | - | T38561 | - | T38571 |
| 45 | - | T38542 | - | T38552 | - | T38562 | - | T38572 |
| 75 | - | T38543 | - | T38553 | - | T38563 | - | T38573 |
| 112.5 | - | T38544 | - | T38554 | - | T38564 | - | T38574 |
| 150 | - | T38545 | - | T38555 | - | T38565 | - | T38575 |
| 225 | - | T38546 | - | T38556 | - | T38566 | - | T38576 |
| 300 | - | T38547 | - | T38557 | - | T38567 | - | T38577 |
| 500 | T38328 | T38548 | T38330 | T38558 | T38332 | T38568 | T38334 | T38578 |
| 750 | T38329 | T38549 | T38331 | T38559 | T38333 | T38569 | T38335 | T38579 |
| D. 12.47 kV Primary | ||||||||
| kVA | 600Y/347 V Sec | 480Y/277 V Sec | 240V Delta Sec | 208Y/120 V Sec | ||||
| Aluminum | Copper | Aluminum | Copper | Aluminum | Copper | Aluminum | Copper | |
| 15 | - | T38580 | - | T38590 | - | T38600 | - | T38610 |
| 30 | - | T38581 | - | T38591 | - | T38601 | - | T38611 |
| 45 | - | T38582 | - | T38592 | - | T38602 | - | T38612 |
| 75 | - | T38583 | - | T38593 | - | T38603 | - | T38613 |
| 112.5 | - | T38584 | - | T38594 | - | T38604 | - | T38614 |
| 150 | - | T38585 | - | T38595 | - | T38605 | - | T38615 |
| 225 | - | T38586 | - | T38596 | - | T38606 | - | T38616 |
| 300 | - | T38587 | - | T38597 | - | T38607 | - | T38617 |
| 500 | - | T38588 | - | T38598 | - | T38608 | - | T38618 |
| 750 | T38336 | T38589 | T38337 | T38599 | T38338 | T38609 | T38339 | T38619 |