1050 HEIDENHAIN Technical Manual MANUALplus 620
6.19.4 PWM frequency with INDRAMAT "POWER DRIVE" inverters
In MP_ampPwmFreq, enter the PWM frequency 4.166 kHz.
6.19.5 PWM frequency with SIEMENS "SIMODRIVE" inverters
The MANUALplus 620 operates with a PWM frequency of 5 kHz. SIEMENS
power modules are normally driven with a PWM frequency of 3.2 kHz
(spindle) and 4 kHz (axes).
The rated current values I
N
are defined for these frequencies. If power
modules are operated with a higher PWM frequency (e.g. 5 kHz), high
temperatures can be caused in these modules in some cases.
This applies particularly to these SIEMENS power modules:
6SN1123-1AA00-0CA0 (as axis module)
6SN1123-1AB00-0CA0 (as axis module)
Machines that are not under full load do not exceed the maximum permissible
temperature.
There are two ways to prevent the undesired heating:
In MP_ampPwmFreq, enter the required PWM frequency (3.333 kHz or
4.166 kHz).
or
Reduce the factor for I
2
t monitoring
or
Reduce rated current I
N
in the table of power modules.
When a new machine is put into service, HEIDENHAIN recommends the
PWM frequency fitting for the axis modules (normally 4 kHz, see the
SIEMENS documentation). If the power module of the spindle gets too warm
in spite of a reduction of the PWM frequency from 5 kHz to 4 kHz, then the
reference value for the I
2
t monitoring or the rated current I
N
must be reduced
in the table of power modules.
A reduction of the PWM frequency has no effect on the maximum
rotational speed, but it means that the axes and the spindle(s) must be
commissioned again.
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