Configuring; Features; Speed Limitation - Siemens SINAMICS S120 System Manual

Configuring

11.1

Features

11.1.1

Speed limitation

The SINAMICS S120 High Frequency Drive was developed for the operation of high-speed
synchronous and induction motors.
Fire with incorrect configuration of drive line-up
When a synchronous motor is used, the DC link voltage can increase excessively and result in
fire with generation of smoke in the event of a power failure and simultaneous generating
operation.
• When using a synchronous motor, you may need to use a Voltage Protection Module or a
In order to minimize the motor losses that occur, HF Drive operates with an output filter (HF Sine
Filter Module), which significantly reduces the pulse-frequency components of the converter
output voltage at the motor terminals.
Operating the HF Sine Filter Module can mean that the motor speed (maximum converter
output frequency) is restricted.
There are two options available to counteract this speed limitation of the motor or restriction of
the maximum converter output frequency:
• Using a Voltage Protection Module (VPM) for synchronous motors
• Operate the HF Drive with a pulse frequency of 32 kHz, if the reduced converter current is
sufficient for the application.
The following table provides an overview of how a possible speed limitation can be avoided.
Table 11-1 Measures to avoid speed limitation
Connect a Voltage Protection Module (VPM)
Operate the HF Drive with 32 kHz pulse frequency (take derating into
consideration)
Limit the DC link voltage with a Braking Module
Requirement: Use of a synchronous motor below the speed limitation of the motor or below the
maximum converter output frequency
High Frequency Drive
System Manual, 10/2020, 6SL3097-5AH10-0BP0
WARNING
combination of Braking Module and Control Supply Module.
Synchronous motors
X
X
11
Induction motors
--
X
157