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Electrical connection
6.6 Motor connection
6.5.5
Inverter connection for different pulse operation
Converters equipped with inputs with higher pulse numbers are available for higher outputs
from approx. 500 kW; these inputs result in lower line harmonics.
Connect the converter to the line supply depending on the number of pulses used:
Table 6- 1
Number of
pulses used
6
12
24
The type code can be found on the rating plate.
6.6
Motor connection
6.6.1
Motor selection
As current-source DC link converter (current source), LOHER DYNAVERT I devices are suitable
for single-motor drives and, with some restrictions, also for multi-motor drives.
The converter must conduct a minimum current during operation. Individual motors can be
switched on and off as long as the current does not fall below this minimum current. The
connected motors must have a minimum no-load current of typically 20 % of the converter
rated current.
• During operation, it is not permissible to disconnect the motor and the converter from
each other. In the event of interruptions, the converter monitoring function responds:
"Overvoltage fault (OF)".
• If, for safety reasons, an isolating point is required between the converter and the motor,
when opening, a leading auxiliary contact at -X2:8 must shut down the converter.
• The converter can also be operated without additional reactors even if very long motor
cables are used.
• The voltage stress on the motor is higher than in the case of line operation; see the
specific technical data.
• Due to the non-sinusoidal current during converter operation, additional motor losses
occur. The continuous torque or the motor power must therefore be reduced compared to
direct line operation. Depending on the counter-torque curve, the lower degree of cooling
also has an effect at low speeds in the case of self-ventilated motors.
66
Line connection dependent on the number of pulses used
Can be recognized
Connection at the converter at –X1:U1, V1, W1
in the type code:
2J.A-...
Three phases
2J.F-...
Two secondary transformer systems each with three phases, i.e. a
2J.D-...
total of six phases.
Both systems must be phase offset by 30°, e.g. using transformer
vector group Dy5d6.
2J.G-...
Four secondary transformer systems each with three phases, i.e. a
total of twelve phases.
The four systems must each be phase offset by 15°, e.g. using two
transformers with vector groups Dy5,25d6,25 and Dy4,75d5,75.
Installation and Operating Instructions for LOHER DYNAVERT I Series 7
Operating Instructions, 10/2022, 4BS0745-002
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