18-pulse autotransformer: Reduce harmonic distortions for long-lasting VFDs

SNC’s 18-pulse autotransformer is a heavy-duty, multi-phase transformer designed to effectively reduce harmonic distortion for variable frequency drive applications.

A variable frequency drive (VFD) is a type of motor controller that varies a motor’s frequency and supplied voltage in order to produce energy savings and greater efficiency.

Harmonic distortion can be detrimental Operation of the VFD and induce conductor and motor degradation. To ensure safe and reliable VFD operation, an 18-pulse autotransformer converts the disrupted raw power from a diesel engine into a wavelength that’s as pure as possible. A smooth wavelength, free of interruptions, results in a clean, reliable motor drive.

VFDs, and therefore 18-pulse autotransformers, are commonly purposed in applications with large drive motors requiring variable speed with variable torque, such as pumps, machine tools, blowers, conveyer systems, A/C motors and more. Industries range from mining to steel mills to marine and more.

What is an 18-pulse autotransformer?

Regardless of the industry or application, an 18-pulse autotransformer is a three-phase transformer that acts as a voltage regulator and is designed to continuously generate electrical pulses of constant amplitude and great velocity.

SNC’s 18-pulse autotransformer is a light, compact unit that offers a smaller footprint. Available with or without an enclosure, our rugged 18-pulse autotransformer also provides multiple aluminum busbar termination options in various sizes to meet your specific application requirements.

18-pulse autotransformer specs

  • 3-phase, 480V primary and 427V secondary
  • 60 Hz
  • 50 to 500 horsepower ratings
  • ETL UL 1561 certified
  • Aluminum windings (While SNC uses aluminum windings and busbars to save on manufacturing costs, a lighter-weight transformer with copper windings and busbars are available upon request.)
  • 180°C (356°F) for better insulation
  • Thermal switches, which are normally closed as an added safety measure

To request a quote or get more information on how SNC can meet your exact specifications with 18-pulse autotransformers, contact our team today.

Product Options

Showing 13 of 13

18 pulse transformer

18-Pulse Autotransformer | 50 HP Rating | P23804

HP Rating

50

kVA

50

TH Height

17"

Mounting Depth

5.75"

Mounting Width

14"

Mounting Height

.562" Hole

Terminal Type LR,T

a

Width

19.125"

Height

25.35"

Depth

11.417"

Shipping Weight

375 lbs.

Watts Loss

1369

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1"

Aluminum Bus Bar Diameter

0.281"

Part Number

P23804

18 pulse transformer

18-Pulse Autotransformer | 60 HP Rating | P23805

HP Rating

60

kVA

60

TH Height

16.5"

Mounting Depth

6.5"

Mounting Width

14"

Mounting Height

.562" Hole

Terminal Type LR,T

a

Width

19.375"

Height

24.9"

Depth

11.716"

Shipping Weight

375 lbs.

Watts Loss

1616

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1"

Aluminum Bus Bar Diameter

0.281"

Part Number

P23805

18 pulse transformer

18-Pulse Autotransformer | 75 HP Rating | P23806

HP Rating

75

kVA

75

TH Height

16.5"

Mounting Depth

6.875"

Mounting Width

16.125"

Mounting Height

.562" Hole

Terminal Type LR,T

a

Width

19.125"

Height

27.75"

Depth

12.002"

Shipping Weight

415 lbs.

Watts Loss

1788

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1"

Aluminum Bus Bar Diameter

0.281"

Part Number

P23806

18 pulse transformer

18-Pulse Autotransformer | 100 HP Rating | P23807

HP Rating

100

kVA

99

TH Height

19.5"

Mounting Depth

6.5"

Mounting Width

18"

Mounting Height

.562" Hole x 1.0" Slot

Terminal Type LR,T

a

Width

22.875"

Height

30.75"

Depth

12.777"

Shipping Weight

530 lbs.

Watts Loss

2218

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1"

Aluminum Bus Bar Diameter

0.281"

Part Number

P23807

18 pulse transformer

18-Pulse Autotransformer | 125 HP Rating | P23809

HP Rating

125

kVA

124

TH Height

21"

Mounting Depth

7.5"

Mounting Width

16"

Mounting Height

.562" Hole

Terminal Type LR,T

a

Width

21.625"

Height

31.75"

Depth

12.091"

Shipping Weight

550 lbs.

Watts Loss

3021

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1"

Aluminum Bus Bar Diameter

0.281"

Part Number

P23809

18 pulse transformer

18-Pulse Autotransformer | 150 HP Rating | P23811

HP Rating

150

kVA

149

TH Height

20.75"

Mounting Depth

7.625"

Mounting Width

19.625"

Mounting Height

.562" Hole

Terminal Type LR,T

b

Width

22.437"

Height

31.376"

Depth

14.402"

Shipping Weight

650 lbs.

Watts Loss

3535

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1"

Aluminum Bus Bar Diameter

0.438"

Part Number

P23811

18 pulse transformer

18-Pulse Autotransformer | 200 HP Rating | P23819

HP Rating

200

kVA

199

TH Height

22"

Mounting Depth

8"

Mounting Width

24"

Mounting Height

.562" Hole

Terminal Type LR,T

b

Width

28.589"

Height

33.25"

Depth

14.539"

Shipping Weight

760 lbs.

Watts Loss

4375

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1"

Aluminum Bus Bar Diameter

0.438"

Part Number

P23819

18 pulse transformer

18-Pulse Autotransformer | 250 HP Rating | P23958

HP Rating

250

kVA

249

TH Height

23.25"

Mounting Depth

8.5"

Mounting Width

24"

Mounting Height

.656" x 1.0" Slot

Terminal Type LR,T

c, b

Width

28.057"

Height

34.563"

Depth

14.34"

Shipping Weight

900 lbs.

Watts Loss

4434

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1.5 (1")

Aluminum Bus Bar Diameter

0.438"

Part Number

P23958

18 pulse transformer

18-Pulse Autotransformer | 300 HP Rating | P23821

HP Rating

300

kVA

298

TH Height

26.25"

Mounting Depth

9"

Mounting Width

24"

Mounting Height

.656" x 1.0" Slot

Terminal Type LR,T

c

Width

26.383"

Height

38.563"

Depth

15.575"

Shipping Weight

1075 lbs.

Watts Loss

4898

Air Flow Required (LFM)

300

Aluminum Bus Bar Thickness

0.25"

Aluminum Bus Bar Width

1.5"

Aluminum Bus Bar Diameter

0.438"

Part Number

P23821

18 pulse transformer

18-Pulse Autotransformer | 350 HP Rating | P23822

HP Rating

350

kVA

348

TH Height

26.25"

Mounting Depth

10"

Mounting Width

24"

Mounting Height

.656" x 1.0" Slot

Terminal Type LR,T

e, c

Width

27.077"

Height

38.563"

Depth

17"

Shipping Weight

1200 lbs.

Watts Loss

6129

Air Flow Required (LFM)

500

Aluminum Bus Bar Thickness

.375" (.25")

Aluminum Bus Bar Width

1.5"

Aluminum Bus Bar Diameter

0.438"

Part Number

P23822

18 pulse transformer

18-Pulse Autotransformer | 400 HP Rating | P23823

HP Rating

400

kVA

398

TH Height

26.5"

Mounting Depth

10"

Mounting Width

25"

Mounting Height

.656" x 1.0" Slot

Terminal Type LR,T

e, c

Width

29.203"

Height

40.375"

Depth

17.468"

Shipping Weight

1400 lbs.

Watts Loss

6643

Air Flow Required (LFM)

500

Aluminum Bus Bar Thickness

.375" (.25")

Aluminum Bus Bar Width

1.5"

Aluminum Bus Bar Diameter

0.438"

Part Number

P23823

18 pulse transformer

18-Pulse Autotransformer | 450 HP Rating | P23824

HP Rating

450

kVA

448

TH Height

27.75"

Mounting Depth

10"

Mounting Width

24"

Mounting Height

.656" Hole

Terminal Type LR,T

e, d

Width

28.637"

Height

41.125"

Depth

18.823"

Shipping Weight

1450 lbs.

Watts Loss

7046

Air Flow Required (LFM)

500

Aluminum Bus Bar Thickness

.375" (.25")

Aluminum Bus Bar Width

1.5 (2")

Aluminum Bus Bar Diameter

0.438"

Part Number

P23824

18 pulse transformer

18-Pulse Autotransformer | 500 HP Rating | P23825

HP Rating

500

kVA

497

TH Height

28.25"

Mounting Depth

10"

Mounting Width

28"

Mounting Height

.812" x 1.0" Slot

Terminal Type LR,T

f, e

Width

30.611"

Height

41.75"

Depth

21.154"

Shipping Weight

2000 lbs.

Watts Loss

7772

Air Flow Required (LFM)

500

Aluminum Bus Bar Thickness

0.375"

Aluminum Bus Bar Width

2 (1.5")

Aluminum Bus Bar Diameter

0.438"

Part Number

P23825

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