Installation
4.2 Electrical Installation
Converter with control units CU250D-2
Operating Instructions, 04/2015, FW V4.7.3, A5E34261542B AB
49
4.2.8
Star-delta motor connection
Depending on your application, you can operate the motor in the star or delta connection
(Y/
Δ).
Examples for operating the converter and motor on a 400 V line supply
Assumption: The motor rating plate states 230/400 V
Δ/Y.
Case 1: A motor is normally operated between standstill and its rated speed (i.e. a speed
corresponding to the line frequency). In this case, you need to connect the motor in Y.
Operating the motor above its rated speed is only possible in field weakening, i.e. the motor
torque available is reduced above the rated speed.
Case 2: If you want to operate the motor with the "87 Hz characteristic", you need to connect
the motor in
Δ.
With the 87 Hz characteristic, the motor's power output increases. The 87 Hz characteristic
is mainly used with geared motors.
Before you connect the motor, ensure that the motor has the appropriate connection for your
application:
Motor is connected in the star or delta configuration
With SIEMENS motors, you will see a diagram
of both connection methods on the inside of the
cover of the terminal box:
•
Star connection (Y)
•
Delta connection (
Δ)
