Curtis PMC 1209B/1221B/1221C/1231C Manual
37
GLOSSARY
6
GLOSSARY:
FEATURES and FUNCTIONS
Acceleration rate
A built-in acceleration rate circuit maintains a maximum rate of power increase
to the motor. If the throttle is applied full on at start-up, the acceleration rate
setting determines how quickly the controller output increases. The standard
setting is such that with the throttle full on, the controller requires approximately
one second to reach full output. This feature contributes to smooth, gentle starts.
The acceleration rate is adjustable via an externally accessible trimpot; see
Section 4 for adjustment instructions. The deceleration rate is
fi
xed, and cannot
be adjusted.
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.
The current limit feature also protects the rest of the system. Because high
current surges during vehicle acceleration are eliminated, stress on the motor and
batteries is reduced and their ef
fi
ciency and service life are improved. 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 maximum motor current can be factory-set to a lower value than the
standard maximum, if requested. In addition, the current limit is
fi
eld adjustable;
see Section 4 for adjustment instructions.
Current multiplication
During acceleration and during reduced speed operation, the Curtis PMC
controller allows more current to
fl
ow into the motor than
fl
ows 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
by a conventional controller (in which the battery current and motor current are
always equal). The current multiplication feature gives vehicles using Curtis PMC
controllers dramatically greater driving range per battery charge.
Environmental protection
Curtis PMC 1209B/1221B/1221C/1231C controllers are housed in rugged
anodized aluminum extrusions that provide environmental protection. Control-
lers must be kept clean and dry, however, to ensure long life.