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Motor Starting Autotransformer

Product Overview & Application


Motor starting autotransformers are a special transformers used in the autotransformer starting of a industrial motors. Autotransformer starting of motors is used widely in starting large industrial motors due to its advantage of providing the highest starting torque with lowest starting line current compared to other reduced voltage starting methods. The reduced voltage taps of the motor starting autotransformer are used to reduce the starting current of the transformer. Contactors switch between the taps, incrementally, increasing the votatge applied to motor as it gets up to speed, while ensuring the starting current is limited. Once the motor reached rated speed, the autotransformer is removed from the circuit entirely, avoiding any unnecessary energization losses..

Features & Benefits

  • Limits the inrush current of the motor significantly.
  • Generates minimal losses durring starting.
  • Suitable for long starting periods
  • Starting voltages can be easily adjusted using the transformer taps.
  • CSA certified: File No. LR 34493.
  • UL listed: File No. E108255.

Product Specification

Capacity  10 to 500HP
Voltage Class  1.2kV
Taps  0%, 50%, 65%, 80% & 100%
Cooling  Self Cooled (ANN / AN)
Frequency  60Hz (50/60Hz Optional)
Conductors  Copper (Cu) Windings
Insulation System  220°C (150°C Rise) (Optional 115°C or 80°C Rise Available)
Impregnation  Polyseter Resin Dipped and Baked
Sound Level  Meets NEMA ST-20
Enclosure Type  Open Core & Coil
Warranty  12 Months (See Warranty and Limitations)
Quality System  ISO 9001:2015 Quality Management System
  • CSA Certified
  • UL Listed
Reference Standards
  • CSA C22.2 No 47
  • CSA C9
  • IEEE C57.12.01
  • IEEE C57.12.91
  • NEMA ST-20
Optional Features & Accessories
  • Suitable for 50Hz Nominal Frequency
  • 115°C or 80°C Temperature Rise
  • Thermal Sensing & Indication
  • Thermometers (Analog/Digital)
  • Thermostat Alarm / Trip (N.O. /N.C. contacts)
  • Anti-Condensation Strip Heaters
  • External Anti-Vibration Pads
  • Type 1, 2, 3R, 4, 4X or 12 Enclosures
  • 304 or 316L Stainless Steel Enclosure
  • Custom Enclosure Finish (Color)