KB Electronics KBPC-225D - Manual (Page 14)

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E. 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 determines the amount of maximum
motor torque in both the Speed Control Mode and Torque Mode. The CL trimpot is factory
set at 150% of the motor current (approx. 22 amps). Also see section IX C. Readjust the
CL trimpot as follows:
1. When jumper J1 is set to the Speed Control Mode, the main potentiometer should be
set at 50% rotation. When jumper J1 is set to the Torque Mode, the main
potentiometer should be set at 100% of full rotation.
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.
F. 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:
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 1.
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.]
G. Timed Current Limit (TCL) – Jumper J5 must be in the "TCL" position, in order for Timed
Current Limit to be operational. This trimpot determines the approximate amount of time
the drive will stay in Current Limit before trip out. The trimpot has an adjustment range
of .5-15 seconds and is factory set for seven (7) 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. (See p. 7, Section III, D 1, "Application
Note," for TCL operation.)
H. Jog Speed (JOG) – This trimpot is operational only when the optional RUN-STOP-JOG
Switch is installed (KB P/N 9340). In the JOG position the JOG trimpot can be adjusted
to set the JOG speed.
IX. FUNCTION INDICATOR LAMPS
The control contains three function LED Indicator Lamps that reflect its operational status.
A. Power On Indicator (ON) – This lamp will glow GREEN when the AC line is connected
to the control.
B. Stop Indicator (STOP) – This lamp will glow YELLOW when the control is placed in the
STOP mode with the Start/Stop Switch.
C. Overload Indicator (OL) – When the motor is loaded to the current limit setpoint (CL
setpoint is established by the setting and the CL trimpot), this lamp will glow RED. If the
control is allowed to stay in CL and then trips out in Timed Current Limit, the OL LED will
remain lighted until the control is restarted with the Start/Stop Switch. If the OL LED
remains lighted 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.)