January 2012 6.18 Spindles 1043
Settings to drive a motor with a U/f component:
Settings in the configuration editor:
MP_posEncoderType = NO_ENCODER
Set a small value for MP_maxAccSpeedCtrl (permissible axis acceleration).
As a general rule:
Select a suitable acceleration and braking ramp to ensure that the maximum
drive current (the lesser of maximum motor current and maximum power
stage current) is not exceeded. If the maximum current is exceeded, the
drives shut down. Controlled braking is not possible in this case.
Entries in the motor table:
During volts-per-hertz (U/f) control mode, no speed encoder is used.
Therefore: Actual speed value = Nominal speed value
Use Module 9164 to determine the speed while the spindle is running, but
not during the acceleration and braking phases.
Column Input Explanation
TYPE UASM Motor model
STR 0 Line count of rotary
encoder
SYS 0 Type of encoder
T-MAX 255 Maximum winding
temperature in °C
R1 Increase the value until the
utilization at standstill or at low
shaft speeds is about 40 %.
Stator resistance cold
If you enter a value of 0 into the STR column of the motor table, the motor
is speed-controlled in an open loop. The machine parameters for current
controller and speed controller have no effect.
Because of the non-linear characteristic of the inverters the spindle should
be operated with a utilization of approx. 40 %. You can attain this value by
adjusting the R1 column in the motor table:
The voltage that is output at standstill results from the product of I0 and R1
in the motor table. R1 should be modified depending on the inverter being
used.
If the utilization at standstill is insufficient, the motor lacks power at
standstill and at low shaft speeds.
If the utilization is too high, the motor overheats.
The oscilloscope shows the actual current instead of the nominal current
(I NOML), since there is no nominal current with U/f components.
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