High-voltage induction motors for variable-frequency drives, 3–6 kV, 200–4000 kW
High-voltage squirrel-cage induction motors for 3–6 kV, rated 200–4000 kW and designed for supply from a medium-voltage frequency converter. The variable-speed drive changes the output of pumps, fans and compressors without throttling and starts powerful machines smoothly, without inrush currents in the grid.
- Rotor type
- squirrel-cage
- Power
- 200–4000 kW
- Voltage / frequency
- 3–6 kV / 50 Hz, 60 Hz
- Shaft height (frame size)
- 355–800
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The line is built to work with medium-voltage VFDs. The motors are made for a supply frequency of 50 or 60 Hz in frame sizes with shaft height from 355 to 800. Smooth speed variation reduces mechanical loads on the unit, and on pumps and fans it removes losses at valves and dampers.
Class F insulation is used with temperature rise to class B. With inverter supply, losses from higher harmonics are added to the basic losses and the winding is exposed to additional impulse overvoltages, so the thermal margin needed here is larger than for a direct-on-line motor. Degree of protection is IP55, mounting arrangements are IM B3, B5 and V1. General requirements comply with IEC 60034-1, and connection dimensions follow IEC 60072.
For this line the manufacturer lists five cooling schemes. IC 511 has a tubular air-to-air cooler with a shaft-mounted fan, and IC 516 repeats the same scheme with an independent fan on the external circuit. IC 611 is based on a top-mounted air-to-air heat exchanger, IC 616 adds an independent external fan, and in IC 666 independent fans are fitted on both circuits. Independent ventilation is needed when the motor runs for long periods at reduced speed with full torque and the shaft-mounted fan can no longer remove the heat. IC 611 is given as the basic option in the specification table. The number of poles and the series designation are not published, and they are specified for the particular machine.
The motors are installed on pumps of main water supply and wastewater systems, network and feed pumps of combined heat and power plants, boiler draft fans, compressors of the gas and chemical industries, main mine ventilation fans, and mill and conveyor drives.
When ordering, the type of frequency converter and the control range are agreed with the manufacturer. The need for insulated bearings and filters at the inverter output is discussed separately, because the life of the bearing assemblies and the condition of the winding insulation depend on it.
Technical specifications
| Rotor type | squirrel-cage |
|---|---|
| Power | 200–4000 kW |
| Voltage / frequency | 3–6 kV / 50 Hz, 60 Hz |
| Shaft height (frame size) | 355–800 |
| Insulation class | F / B |
| Degree of protection | IP55 |
| Cooling | IC 511, IC 516, IC 611, IC 616, IC 666 (per the section); IC 611 in the table |
| Mounting arrangement | IM B3, B5, V1 |
| Connection dimensions | IEC 60072 |
| Standard | IEC 60034-1 |
Request a price and lead time
High-voltage induction motors for variable-frequency drives, 3–6 kV, 200–4000 kW. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What voltage and power do the motors for frequency control have?
The motors are rated 200–4000 kW at 3–6 kV, with a supply frequency of 50 or 60 Hz. Shaft height is from 355 to 800.
Which cooling should be chosen for operation at low speed?
For long operation at reduced speed with full torque, schemes with independent ventilation IC 516, IC 616 or IC 666 are suitable. The basic version in the table has IC 611 cooling.
What is agreed when ordering a motor for use with a VFD?
The type of frequency converter, the control range, and the need for insulated bearings and inverter output filters. Class F insulation with temperature rise to class B gives a margin for losses from higher harmonics.
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