3.3 kV, 40,000 HP

The TMdrive-70 from TMEIC is a high-power, water-cooled, precise and rugged, fully digitalized vector-controlled three-level pulse width modulated (PWM) induction and synchronous motor drive system.

The TMdrive-70 uses the very latest but proven power switching technology, the injection enhanced gate transistor (IEGT). The IEGT is a voltage-switched power device with low on-state voltage and high-speed switching.

Flexible arrangement of converter, inverter, and cooling units gives high-power density and a very small required floor space and lower installation costs.


The high-power TMdrive-70 can be used in many applications, including:

  • Precision-controlled processes with high dynamic performance requirements such as large metal mill main drives.
  • Large fan, pumping and compressor applications. The TM-70 provides accurate speed control and high efficiency while eliminating the need for high maintenance mechanical flow control devices.
  • Grinding mills with high overloads and impact loads.
  • Mine hoists, with high overloads and overhauling loads.

General Specifications

The TM-70 drive includes a fully digitalized vector controlled three-level pulse width modulated (PWM) inverter and the choice of either an active regenerative AC-to-DC converter or a diode converter.

  • Power levels 5000 kVA to 40,000 kVA at 3300 output volts (any output voltage through output matching transformer)
  • Low harmonic distortion to the power system – meets IEEE-519-1992 guidelines with the available IEGT active, regenerative power converter.
  • More economical diode AC-to-DC power conversion with 12 and 24 pulse configurations to supply non-regenerative loads such as fans or pumps.
  • Induction or synchronous motor compatibility.
  • Uses the TMEIC family common control platform, including PP7 microprocessor, control I/O, and the TMdrive Navigator tool.

TM-70 power conversion components include:

  • TMdrive-70 inverters (8,000 and 10,000 frames) that can be paralleled up to 40,000 kVA capacity.
  • TMdrive-D70 diode non-regenerative AC-to-DC converters (8,000 frame) that can be configured in 12 or 24 pulse arrangements.
  • TMdrive-P70 regenerative AC-to-DC converters (8,000 and 10,000 frames) that can be paralleled in combination with inverters up to 40,000 kVA capacity.
TMdrive-70 Features and Benefits
Design Feature
Customer Benefit

IEGT power switch technology in the inverter and regenerative converter power bridges

High-speed switching coupled with the three-level power bridge delivers a smooth sine wave to the motor and power system

Low on-state IEGT voltage yields high efficiency

High-Speed Switching 

The IEGT is switched at a rate of 500 Hz, even at power levels up to 10,000 kVA

Motor and Power System Friendly

Higher chopping frequency lowers the torque ripple in the motor and load, and lowers harmonics fed back into the power system.

Low power Gate Drive signals used to turn IEGTs on and off.

Low power level voltage switched gate circuit has far fewer components than IGCT current-controlled gate, increasing inherent reliability

Frequency Modulation Control (not traditional PWM) power switching scheme and three-level power bridge control

Harmonics fed back into the power system are reduced to less than IEEE-519-1992 recommendations with no filters

Water-cooling technology for the power bridge

Reduced footprint, saving valuable factory floor space

Modular design of power bridge, with each phase leg having its own set of quick disconnects

Minimizes maintenance time

Control cards common to the TMdrive family

Reduces required spares and increases spares' availability

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