Specifications

Curtis PMC 1223/33, 1225/35, 1227/37 Manual
A-3
APPENDIX A: GLOSSARY
Current limiting
Curtis PMC controllers limit the motor current to a preset maximum. This feature
protects the controller from damage that might result if the current were limited
only by motor demand. PWM output to the power section is reduced until the
motor current falls below the set limit level.
In addition to protecting the controller, the current limit feature also
protects the rest of the system. By eliminating high current surges during vehicle
acceleration, stress on the motor and batteries is reduced and their efficiency
enhanced. Similarly, there is less wear and tear on the vehicle drivetrain, as well
as on the ground on which the vehicle rides (an important consideration with
golf courses and tennis courts, for example).
The current limit is programmable—see Section 3, page 40.
Current multiplication
During acceleration and during reduced speed operation, the Curtis PMC
controller allows more current to flow into the motor than flows out of the
battery. The controller acts like a dc transformer, taking in low current and high
voltage (the full battery voltage) and putting out high current and low voltage.
The battery needs to supply only a fraction of the current that would be required
if a resistive controller were used. The current multiplication feature gives vehicles
using Curtis PMC controllers dramatically greater driving range per battery
charge.
Deceleration rate
The deceleration rate is the time required for the controller to decrease from 100%
duty factor to zero. The deceleration rate and reverse deceleration rate can be
defined separately. The deceleration rate controls how quickly the vehicle slows to
a stop when it is moving forward. The reverse deceleration rate controls how
quickly the vehicle slows to a stop when it is moving in reverse. The two
deceleration rates are independent because it may be desirable to define a faster
deceleration rate in the reverse direction.
The deceleration curve is controlled by the dynamic throttle response,
which is linear. The deceleration rates are programmable—see Section 3, page 29.
Emergency reverse
The emergency reverse feature is available only on 123X controllers (1233/1235/
1237). Emergency reverse is activated when the keyswitch is On and the
emergency reverse switch (the BB, or “belly button” switch) is pressed. After the
BB switch is released, normal controller operation is not resumed until zero