KB Electronics KBWD-15 - Manual (Page 7)

B. Maximum Speed (MAX) — The MAX trimpot is used to set the maximum voltage of the drive. Adjust
the MAX trimpot as follows:
1. Rotate Main Potentiometer to maximum speed position (full clockwise).
2. Adjust MAX trimpot setting to desired setting of motor speed. (Caution: Do not exceed rated RPM
of motor.)
C. Acceleration (ACCEL) — The ACCEL trimpot sets the amount of time it takes the control to reach full
output. The trimpot is factory set to one (1) second. If more rapid acceleration is desired, rotate the
trimpot counterclockwise.
Note: Rapid ACCEL setting may cause the current limit circuit to activate which will extend the
acceleration time.
For a longer acceleration time, rotate ACCEL trimpot clockwise. 50% rotation represents approximately
seven (7) seconds and full rotation is approximately fifteen (15) seconds.
D. Current Limit (CL) — This trimpot is used to set the maximum amount of DC current that the motor can
draw. The amount of DC current is directly proportional to the motor torque. The CL trimpot is factory
set at 150% of the current established by the Plug-in Horsepower Resistor ® selection. (See table 2, p.
5.) Readjust the CL trimpot as follows: (Note: The "OL" indicator will light when the control is in
CL.)
1. Turn CL trimpot to minimum (CCW) position. Be sure proper value Plug-in Horsepower Resistor
®
is installed.
2. Wire in a DC ammeter in series with armature lead. Lock shaft of motor.
3. Apply power. Rotate CL trimpot CW until desired CL setting is reached (factory setting is 1.5 times
rated motor current).
CAUTION
1. Adjusting the CL above 150% of motor rating can cause overheating and demagnetization of
some PM motors. Consult motor manufacturer.
2. Do not leave the motor in a locked condition for more than a few seconds since armature
damage may occur.
E. IR Compensation (IR) — The IR comp circuit is used to stabilize motor speed under varying loads.
Note: If control is in Tach Feedback mode, the IR trimpot should be set to minimum - CCW.
Readjust the IR trimpot as follows:
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1. Run the motor at approximately 30-50% of rated speed under no load and measure actual speed.
2. Load the motor to rated current. Rotate IR trimpot so that the loaded speed is the same as the
unloaded speed measured in E1.
Control is now compensated so that minimal speed change will occur over a wide range of motor
load.
Note: Too much IR Comp will cause unstable (oscillatory) operation.
F. Timed Current Limit (TCL) – This trimpot determines the approximate amount of time the drive will stay
in Current Limit before “timing out.” The trimpot has an adjustment range of 1 – 7 seconds and is factory
set for three (3) seconds. The trimpot can be reset according to the desired trip time. Rotating the
trimpot clockwise increases the trip time. This function provides motor overload protection.
IX. FUNCTION INDICATOR LAMPS
The control contains two LED indicator lamps that reflect operational status.
A. Power On Indicator (ON) – This lamp will glow GREEN when the AC line is connected to the control.
B. Overload Indicator (OL) – When the motor is loaded to the current limit setpoint (CL setpoint is
established by the value of the Plug-in Horsepower Resistor ® and the CL trimpot) this lamp will glow RED.
If the control is allowed to stay in CL and then “times out” in Timed Current Limit, the CL LED will remain
illuminated, until the control is restarted with the On/Off or Inhibit Switch. If the OL LED remains
illuminated during control operation, a fault condition may exist. Possible causes for this condition are
as follows:
1. Motor is overloaded - check motor amps with DC ammeter in series with armature. (If motor is shunt
type, field may be open or not receiving proper voltage.)
2. Motor may be defective - check motor for shorts or grounds.
3. The CL may be set too low - check value of Plug-in Horsepower Resistor
® and CL trimpot.
Note: The horsepower ranges marked on the Plug-in Horsepower Resistor ® are marked for SCR
controls (See table 2 p. 5).
NOTE: In some applications, especially those requiring the motor to cycle on and off or to be changed
from one speed to another, the OL indicator may blink indicating a transient overload. This may be a
normal condition for the application.
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