24
Curtis 1268 Manual,
Rev. D
The field mapping parameters determine how much field current is applied for
a given armature current.
M1/M2 FWD FIELD MIN
The
forward minimum field current limit
parameter defines the minimum
allowed current in the motor’s field winding when the vehicle is traveling in
the forward direction. Its setting may affect the vehicle’s maximum speed and,
to some extent, the smoothness with which the vehicle starts and transitions
between drive and regen. If
FWD FIELD MIN
is set high, the vehicle’s top speed will
be reduced, but torque bumps may be evident when the vehicle is inched or
changes direction.
One of the greatest advantages of the
FIELD MIN
parameter is that it will
prevent uncontrolled acceleration when the vehicle goes down ramps or when
it is unloaded from trucks, etc.
REV FIELD MIN
The
reverse minimum field current limit
parameter defines the minimum
allowed current in the motor’s field winding when the vehicle is traveling in
the reverse direction.
FIELD MAX
The
maximum field current limit
parameter defines the maximum allowed
current in the motor’s field winding. Its setting will determine the motor’s
maximum torque during drive operation, and will limit the power dissipation
in the field winding itself.
NEG FIELD MAX
The
negative maximum field current limit
parameter defines maximum al-
lowed current in the motor’s field winding during regen braking.
FLD MAP START / NEG FLD MAP ST
The
field map start
parameter defines the armature current at which the field
current starts to increase from the
FIELD MIN
value (see current limit parameters).
The
negative field map start
parameter works similarly; it defines the negative
armature current at which the field current starts to increase from the
FIELD MIN
value.
Care should be taken to ensure that high
FIELD MAP START
values do not
move the motor’s operating characteristics outside its safe commutation area.
3 — PROGRAMMABLE PARAMETERS: Field Mapping Parameters
Field Mapping Parameters
