Setting up Compax3
Optimize
motor reference point and switching frequency of the power output stage
38
I11 T11 192-120101 N6 - March 2004
4.1.2.
Optimize motor reference point and switching frequency of the
power output stage
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 power output stage 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 power output stage switching frequency depends on the performance
variant of the Compax3 device.
The respective Compax3 devices can be set as follows:
Resulting nominal and peak currents depending on the switching
frequency of the power output stage
Optimization of the
motor reference
point
Optimizing the
switching frequency
of the power output
stage
