Curtis 1243
GEN
2 Manual
64
5 — VEHICLE PERFORMANCE ADJUSTMENT
STEP
2. If the transition is too abrupt: increase the Taper Rate and/or set
the Variable Braking parameter to On. Secondary adjustments
can be made by increasing the Accel Rate.
STEP
3. If the transition is too slow: decrease the Taper Rate and set
Creep Speed to 5% or greater. Secondary adjustments can be
made by decreasing the Accel Rate, increasing the Current Ratio,
or increasing the Quick Start parameter value.
8
Ramp Climbing
The vehicle response to increased gradients such as loading ramps can be tuned
via the Field Map parameter. Decreasing the Field Map parameter allows faster
vehicle speeds while climbing ramps, but it also has the effect of reducing the
ability of the controller to generate torque in the vehicle
’
s mid range speeds.
STEP
1. If faster vehicle speed is desired when climbing ramps, decrease
the Field Map parameter value until the desired ramp climbing
speed is attained. It should be noted that if the motor
’
s torque
capability is exceeded under the conditions of load weight and
ramp gradient, vehicle speed will be limited by the motor
’
s
capability and the desired vehicle speed may not be attainable.
The system will
fi
nd a compromise point at which suf
fi
cient
motor torque is generated to climb the ramp at an acceptable
speed. If the Field Map parameter value is reduced to 0% and the
desired speed is still not attained, the system is being limited by
the motor
’
s torque capability under these operating conditions.
CAUTION:
be careful when reducing the Field Map parameter
since at low Field Map values it is possible that the motor could
be operated outside its safe commutation region.
STEP
2. If the drive system cannot produce suf
fi
cient torque for a fully
loaded vehicle to climb the desired ramp, try increasing the Field
Map, Field Max, and/or Drive Current Limit parameters. The
impact of increasing these parameter values on other driving
characteristics must be evaluated. Increasing the Field Max will
provide more
fi
eld current, and increasing the Drive Current
Limit will provide more armature current. If the Field Max is set
at the manufacturer
’
s speci
fi
ed limit and the Drive Current Limit
is set at the rated maximum, then vehicle speed up the ramp is
limited by the motor or the vehicle
’
s gearing and cannot be
increased by tuning the controller.
NOTE
: To determine if the
controller
’
s armature current is at its set value during ramp
climbing, read the
“
Arm Current
”
in the programmer
’
s Monitor
Menu.