5.3 Operation on foreign converters
Principally, operating MS2N motors on foreign converters is possible. The fol-
lowing requirements and limitations on foreign converters must be observed.
Danger of explosion or material damage due to
overload!
Observe the following requirements for safe motor operation on foreign convert-
ers. Connection of all necessary sensors and additional devices for a safe opera-
tion and their evaluation lies in the sole responsibility of the plant manufacturer
or operator.
Requirements on the power output stage
● Converter with pulse width modulation
● Pulse frequency 4 kHz …16 kHz
Voltage load of the motor
During converter operation, the motor underlies a higher voltage load (insulation
system, bearing) than on a sinusoidal source voltage only.
Standard values for peak voltage and rate of rise of voltage:
● Peak voltage U
pk
on motor clamps ≤ 1.56 kV
● Rate of rise of voltage du/dt ≤ 5 kV/μs
Maximum allowed limit load:
In the case of critical rate of rise of off-state voltage du/dt ≥ 5 kV/µs, the limit
values (peak voltage, voltage rise time) according to limit curves A according to
DIN VDE 0530-25 (VDE 0530-25):2009-08 (Figure 14 Limit curve A) must be
kept. Therefore, observe the limit values for voltage rise time and critical rate of
rise of off-state voltage.
Limit values for voltage rise time and critical rate of rise of off-state voltage:
● Voltage rise time > 0.17 µs
● Critical rate of rise of off-state voltage du/dt < 8 kV/µs
Monitoring functions
● Speed monitoring of maximum permissible speed
● The motor load must not exceed the permitted continuous operation charac-
teristic curve. The converter setting data for controlling and monitoring must
comply with the type code data.
● Temperature control to protect from thermal overload
– The temperature sensor of the motor winding must be connected and eval-
uated on the converter (ensure monitoring function, observe polarity of
temperature sensor, limit switch-off temperature according to chapter
4.2.3 "Thermal motor protection" on page 13).
MS2N Synchronous Servomotors
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Operating conditions and handling
R911347581_Edition 04 Bosch Rexroth AG