Connecting The Motor In A Star Or Delta Connection; Overview - Siemens SINAMICS G115D Operating Instructions Manual

Wiring
4.10 Connecting the motor
4.10.2

Connecting the motor in a star or delta connection

4.10.2.1

Overview

Standard asynchronous motors up to a rated power of approximately 3 kW are normally
connected in a star/delta connection (Y/Δ) at 400 V/230 V. For a 400 V line supply, you can
connect the motor to the converter either in a star or in a delta connection.
Function description
Operating the motor in a star connection
Operating the motor in a delta connection with 87 Hz characteristic
The motor only goes into field weakening above 87 Hz.
The higher motor power when operated with an 87 Hz characteristic has the following
disadvantages:
• The converter must supply approximately 1.73x current. Select a converter based on its
rated current - and not its rated power.
• The motor temperature increases more significantly than when operated with f ≤ 50 Hz.
• The motor must have windings that are approved for a voltage > rated voltage U
• As the fan impeller rotates faster, the motor has a higher noise level than operation with
f ≤ 50 Hz.
72
In a star connection, the motor can provide its
rated torque M
quency f .
N
Rated voltage U
frequency f = 50 Hz.
N
The motor goes into field weakening above
the rated frequency. In field weakening, the
available motor torque decreases linearly with
1/f. In field weakening, the available power
remains constant.
In a delta connection, the motor is operated
with a voltage and frequency above its rated
values. As a consequence, the motor power is
increased by a factor
In the range f = 0 ... 87 Hz, the motor can out-
put its rated torque M
The maximum voltage U = 400 V is available at
a frequency of f =
Operating Instructions, 12/2020, FW V4.7 SP13, A5E48681219B-002
in the range 0 ... rated fre-
N
= 400 V is available at a rated
N
≈ 1.73.
.
N
× 50 Hz ≈ 87 Hz.
.
N
SINAMICS G115D distributed drive