Electromechanical converters (motor-generator sets) 10–25 000 kVA, including for transformer testing
Electromechanical converters rated 10 to 25 000 kVA and more, in which an electric motor drives a synchronous generator. The sets galvanically isolate the load from the mains and convert frequency. They are used to supply critical equipment and at test stations of transformer factories.
- Power
- 10–25 000 kVA and more
- Input
- 50 or 60 Hz
- Output
- 50, 60 or 400 Hz as standard; 25–1200 Hz to order; continuously adjustable frequency with a VFD on the motor
- Distortion
- up to 1 % THD (linear)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The design fully isolates the generator from the supply network, so the generator and the equipment it feeds are protected from voltage sags, surges and impulses. The generator is built to NEMA standards. It withstands short circuits and overloads of 300 % of rated current for 10 s. Careful winding design gives distortion of up to 1 % THD (linear). The neutral is usually not connected, so with a balanced load the third harmonic is practically absent, and a properly chosen winding pitch and slot skew suppress the fifth, seventh and higher harmonics.
High-voltage versions with form-wound windings give higher output voltages than machines with random-wound windings, and simplify or eliminate the input or output transformer. Exciters are brushless, and horizontal single-shaft sets have no coupling, gearbox or belt. Service life to major overhaul is 100 000 h, and the input power factor is 1.0 without compensation. Components are standard, so spare parts are available even for sets that have run for decades.
With a 50 or 60 Hz input, outputs of 50, 60 or 400 Hz are available as standard. To order, sets are built with a fixed frequency of 25–1200 Hz or with a continuously adjustable frequency, when the motor is fed from a frequency converter. Synchronous sets 50–50, 60–60, 50–60 and 60–50 Hz are built up to 25 000 kVA for voltages from 120 V to 13.8 kV, 60–400 Hz sets up to 400 kVA, and 50–400 Hz sets up to 300 kVA.
Several configurations exist for transformer testing. Sets of 1500/1800 rpm (50–50 or 60–60 Hz) supply no-load and heat run tests, while 600 rpm sets convert 50↔60 Hz when the rated frequency of the transformer differs from the local one. Variable frequency sets make it possible to select any frequency in the 50–60 Hz range. Dual MGG sets, for example 50–60 Hz and 100–200 Hz, have two generators that can be driven by a single motor. For induced voltage tests, 150/180 Hz generators are supplied, along with smaller machines for 200/240, 300/360 and 400 Hz, with low distortion and a low partial discharge level.
The set is usually supplied with a PLC panel programmed at the factory. The panel contains a motor starter, an output breaker, metering, protection relays and a voltage regulator, and manual and automatic synchronisation are available. The panel is mounted on the set, separately on the floor or on a wall. Applications cover test stations, power supply for data centres and complex electrical installations, and frequency conversion.
Technical specifications
| Power | 10–25 000 kVA and more |
|---|---|
| Input | 50 or 60 Hz |
| Output | 50, 60 or 400 Hz as standard; 25–1200 Hz to order; continuously adjustable frequency with a VFD on the motor |
| Distortion | up to 1 % THD (linear) |
| Overload | 300 % of rated current for 10 s |
| Service life | 100 000 h to major overhaul |
| Input power factor | 1.0 without compensation |
| Transformer testing | 50/60 Hz no-load and heat run; 150/180 Hz (up to 400 Hz) induced voltage test |
| Control | PLC panel: starter, breaker, metering, protection relays, voltage regulator, synchronisation |
Request a price and lead time
Electromechanical converters (motor-generator sets) 10–25 000 kVA, including for transformer testing. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
Which sets are needed for induced voltage testing of transformers?
Usually 150 or 180 Hz generators, and smaller machines for 200/240, 300/360 and 400 Hz. They have low distortion and a low partial discharge level.
What power and frequencies do the motor-generator sets have?
Power is 10 to 25 000 kVA and more. With a 50 or 60 Hz input, outputs of 50, 60 or 400 Hz are available as standard, and 25–1200 Hz to order.
What overload does the set generator withstand?
The generator withstands 300 % of rated current for 10 s, with voltage distortion of up to 1 % THD. Service life to major overhaul is 100 000 h.
Similar equipment from other manufacturers
