LEESON NEMA 4X SCR Control: 174903.00 (Obsolete) - Manual (Page 5)

CONTROL FEATURES
4
MIN. SPEED (minimum speed) - Allows adjustment of the motor speed when the speedpot
is set at minimum (CCW). This permits the user to eliminate the “deadband” on the main speed
control permitting zero calibration. Clockwise rotation of “MIN” trimpot increases minimum
motor speed.
MAX. SPEED (maximum speed) - provides for adjustment of the motor speed when the
speedpot is set at maximum (CW). This permits the user to eliminate the top end “deadband”,
which will provide full speed at maximum rotation. Rotation of the “MAX” trimpot in the clockwise
direction increases the maximum motor speed.
ACCEL (acceleration) - allows adjustment of the motor acceleration from a minimum of 0.5
seconds to approximately 0.8 seconds. The deceleration time depends on the ACCEL setting.
I. R. COMP (speed regulation) - adjusts the control output to compensate for speed changes
caused by varying motor loads. As the motor load is increased, I.R. COMP increases the
voltage output of the control. Clockwise rotation of the “I.R. COMP” trimpot will increase
compensation.
CUR. LIM. (current limit) - provides protection from excessive armature current by limiting the
maximum armature current the control can provide. This enables adjustment of the maximum
torque the motor can deliver. Current limit adjustment (CUR LIM) is set at 125% of the rated
motor current (torque) based on horsepower. Clockwise rotation of the “CUR LIM” trimpot
increases the current (torque) the control will provide.
INHIBIT TERMINAL PIN (P2) - allows the user a choice of stopping and starting hard (fast) or
stopping hard with a soft start through an adjustable acceleration ramp, without breaking the
AC lines (see page 12).
TERMINAL STRIP - allows for connection of AC lines, motor leads, motor field (if needed), and
speed potentiometer.
WARNING
AT NO TIME SHOULD CIRCUIT CONTINUITY
BE CHECKED BY SHORTING TERMINALS WITH
A SCREWDRIVER OR OTHER METAL DEVICE