Setting
up Compax3
C3I12T11
100
192-120113 N08 C3I12T11 - December 2010
4.1.4.
Optimize motor reference point and switching frequency of
the motor current
The motor reference point is defined by the reference current and the reference
(rotational) speed.
Standard settings are:
Reference current = nominal current
Reference (rotational) speed = nominal (rotational) speed
These settings are suitable for most cases.
The motors can, however, be operated with different reference points for special
applications.
By reducing the reference (rotational) speed, the reference current can be
increased. This results in more torque with a reduced speed.
For applications where the reference current is only required cyclically with long
enough breaks in between, you may use a reference current higher than I
0
. The
limit value is however reference current = max. 1.33*I
0
. The reference (rotational)
speed must also be reduced.
The possible settings or limits result from the respective motor characteristics.
Caution!
Wrong reference values (too high) can cause the motor to switch off during
operation (because of too high temperature) or even cause damage to the motor.
The switching frequency of the power output stage is preset to optimize the
operation of most motors.
It may, however, be useful to increase the switching frequency especially with
direct drives in order to reduce the noise of the motors. Please note that the power
output stage must be operated with reduced nominal currents in the case of
increased switching frequencies.
The switching frequency may only be increased.
Caution!
By increasing the motor current switching frequency, the nominal current and the
peak current are reduced.
This must already be observed in the planning stage of the plant!
The preset motor current switching frequency depends on the performance variant
of the Compax3 device.
The respective Compax3 devices can be set as follows:
Optimization of the
motor reference
point
Optimization of the
switching frequency
