KEB COMBIVERT F5 Instruction Manual page 77

Initial Start Up
LF.33 provides an offset to the gain value at low speeds. Again this parameter provides two
adjustments; one for acceleration and one for deceleration. During starting and stopping
it is necessary to have higher gain values to overcome friction as well as maintain good
control. The total integral gain value is the sum of LF.32 and LF.33 at low speeds.
US.20 and US.21 defi ne the corner speeds where the gain begins to ramp up and where
the gain reaches the maximum value. For gearless application it may be necessary to
increase US.21 to around 100 ft/min and decrease US.20 to 3 ft/min
Common problems during starting and their solutions
Speed
Speed
Speed
LF.33 = 1000
Speed lags the command on take off. This is typical with
worm gear machines when trying to break free. The
start feels very hard or abrupt. Raise in steps of 500.
t
LF.33 = 3000
Higher KI Offset value aids the torque build during
starting. Helps to over come break away torque of
machine. Actual speed tracks the command.
t
LF.33 = 6000
High KI Offset value causing vibration or audible noise
in the motor at take off. Lower in steps of 500.
t
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