8
05.01
8.11 Series reactor
8-302
©
Siemens AG 2012 All Rights Reserved
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
If the motor data are not known, then for motors with a high current (rated
current
>
85 A), the converter current should be dimensioned for a pulse
frequency of 4950 Hz. This means that a drive converter reduction factor of
approx. 83% is obtained.
For motors that require a higher motor frequency than 500 Hz, the drive con-
verter pulse frequency must be increased.
The following formula applies:
f
T
6
•
f
max mot
f
T
Inverter clock cycle frequency of the drive converter in Hz,
refer to Chapter 5.4.1
f
max mot
Max. motor stator frequency
It should be noted that for inverter clock cycle frequencies above 3200 Hz,
the module current rating must be reduced or, if required, a module with a
higher–current rating must be selected.
The max. field–weakening range for induction motor operation is limited.
The following relationships apply:
n
max
n
FS
2 for high–speed motors (max. output frequency > 300 Hz),
5 for wide–range motors
Standard motors
n
max
Max. motor speed
n
FS
Speed at the start of field weakening for the motor
U
DC link
1.6
V
nmot
An approximate value can
be calculated with n
FS
•
n
n
•
(refer above)
If a motor is changed–over from delta to star operation and vice versa, and
auxiliary and main contactors are required for each motor. The motor con-
tactors must be mutually interlocked. The changeover is only made when
the pulses are inhibited using select terminal signals. When the changeover
command is issued, the motor data set is re–loaded and the auxiliary con-
tactors are controlled via the selector relay.
Parallel operation of several induction motors, refer to Chapter 8.12.1.
The voltage drop across a series reactor depends on the motor current and
the motor frequency. If an unregulated infeed is used, the maximum rated
motor voltage depends on the line supply voltage available.
If these guide values are not observed, then this can have a negative impact
on the power (lower power) in the upper speed range.
8 Important Circuit Information
11.05
