User Manual

Curtis 1268 Manual, Rev. D 37

step 6. Set

NEG FIELD MAX at or below the FIELD MAX setting.

If the controller is tuned such that the system is operating

outside the motor’s safe commutation region, there will be au

dible and visual indications. Under normal operation, the mo

tor will emit a whine with a pitch that increases with increasing

rotation speed. If a “scratchy” sound is also heard, this is usually

an indication that pin arcing is occurring in the motor and it is

operating outside its safe commutation region. This operation is

normally accompanied by a strong smell from the motor. If the

brushes and commutator bars are visible, arcing may be visible.

The further outside the safe commutation region the motor is

operating, the worse the arcing will be. Operation outside the

safe commutation region is very detrimental to the motor.

The FIELD MIN and possibly also the FIELD RAMP should be increased

until the indications of arcing stop. Decreasing

FIELD MAP START

will also help to move operation back into the safe commutation

region.

The typical default ﬁeld map settings are as follows.

5 — TUNING GUIDE

Further tuning of the ﬁeld maps is described in procedures

, and