18-Pulse Autotransformers

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.

Product features

  • 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

Product Options

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    Showing 13 of 13

    18-Pulse Autotransformer | 50 HP Rating | P23804
    18 pulse transformer

    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 Autotransformer | 60 HP Rating | P23805
    18 pulse transformer

    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 Autotransformer | 75 HP Rating | P23806
    18 pulse transformer

    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 Autotransformer | 100 HP Rating | P23807
    18 pulse transformer

    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 Autotransformer | 125 HP Rating | P23809
    18 pulse transformer

    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 Autotransformer | 150 HP Rating | P23811
    18 pulse transformer

    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 Autotransformer | 200 HP Rating | P23819
    18 pulse transformer

    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 Autotransformer | 250 HP Rating | P23958
    18 pulse transformer

    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 Autotransformer | 300 HP Rating | P23821
    18 pulse transformer

    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 Autotransformer | 350 HP Rating | P23822
    18 pulse transformer

    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 Autotransformer | 400 HP Rating | P23823
    18 pulse transformer

    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 Autotransformer | 450 HP Rating | P23824
    18 pulse transformer

    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 Autotransformer | 500 HP Rating | P23825
    18 pulse transformer

    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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