Siemens SINAMICS G120C User Manual

8.20.2.2 Optimizing motor starting
Overview
After selection of the U/f characteristic, no further settings are required in most applications.
In the following circumstances, the motor cannot accelerate to its speed setpoint after it has
been switched on:
• Load moment of inertia too high
• Load torque too large
• Ramp-up time p1120 too short
To improve the starting behavior of the motor, a voltage boost can be set for the U/f
characteristic at low speeds.
Requirement
The ramp-up time of the ramp-function generator is, depending on the motor rated power, 1 s
(<1kW) …10s (>10kW).
Function description
Setting the voltage boost for U/f control
The converter boosts the voltage corresponding to the starting currents p1310…p1312.
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S
S
U
S
S
8
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Figure8-48 The resulting voltage boost using a linear characteristic as example
Increase parameter values p1310 … p1312 in steps of ≤5%. Excessively high values in
p1310 ... p1312 can cause the motor to overheat and switch o󹪜 (trip) the converter due to
overcurrent.
If message A07409 appears, it is not permissible that you further increase the value of any of
the parameters.
Procedure
1. Switch on the motor with a setpoint of a few revolutions per minute.
2. Check whether the motor rotates smoothly.
Advanced commissioning
8.20Motor control
SINAMICS G120C Converters
304 Operating Instructions, 02/2023, FW V4.7 SP14, A5E34263257B AK

Siemens SINAMICS G120C Specifications

General

Communication Interfaces	PROFINET, PROFIBUS, USS, Modbus RTU
Protection Class	IP20
Ambient Temperature	-10°C to +50°C
Storage Temperature	-40°C to +70°C
Power Range	0.55 kW to 132 kW
Voltage Range	380 V to 480 V
Output Voltage	0 V to Supply Voltage
Frequency Range	0 Hz to rated output frequency
Control Modes	Vector control with encoder
Protection	Overload, overvoltage, undervoltage, short circuit, ground fault
Relative Humidity	5% to 95%, non-condensing
Altitude	Up to 2000 m without derating