Function description
Operating the motor in a star connection
I
I
1
8
8
1
I
0
0
1
I
3
3
1
9
+]
9
8
8
:
8
8
9
9
:
:
In a star connection, the motor can provide its
rated torque M
N
in the range 0 … rated fre‐
quency f
N
.
Rated voltage U
N
= 400 V is available at a rated
frequency f
N
= 50 Hz.
The motor goes into field weakening above the
rated frequency. In field weakening, the avail‐
able motor torque decreases proportionally
with 1/f. In field weakening, the available pow‐
er remains constant.
Operating the motor in a delta connection with 87 Hz characteristic
I
I
1
෭෪I
1
8
8
1
෭෪8
1
෭෪3
1
9
9
+]
+]
I
0
0
1
I
3
3
1
9
8
8
:
8
8
9
9
:
:
In a delta connection, the motor is oper‐
ated with a voltage and frequency above
its rated values. As a consequence, the
motor power is increased by a factor
√3 ≈ 1.73.
In the range f = 0 … 87 Hz, the motor can
output its rated torque M
N
.
The maximum voltage U = 400 V is avail‐
able at a frequency of f = √3 × 50 Hz ≈
87 Hz.
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
N
.
• As the fan impeller rotates faster, the motor has a higher noise level than operation with
f ≤ 50 Hz.
Installation
4.3 Electrical Installation
Distributed converter for SIMOGEAR geared motors
Operating Instructions, 10/2020, FW V4.7 SP13, A5E31298649B AL
75