Electronics AC - Manual (Page 3)

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1. PRODUCT DESCRIPTION
The Model AC Amperage Controller is used with wheel-type shot peening and blast cleaning
machines. It is designed to measure and control the rate of flow of steel shot passing through a
special normally closed magnetic valve called a MagnaValve. A digital display is provided for in-
dications of motor amps. A 0-10Vdc output signal is available for a remote indicator or a strip-
chart recorder. High and low alarms are set to bracket the requested amperage setting. The
alarm bandwidth is adjustable from the front panel. Either local (front panel) or remote 0-10Vdc
setpoint
commands may be used.
2. THEORY OF OPERATION
The AC Controller compares the motor current setpoint with the actual motor current sends a
power signal to the MagnaValve. If the desired amperage is not achieved within an adjustable
period, a high/low alarm relay will be triggered, outputting a signal that may be used to inhibit
further machine operations and signal the operator.
3. PRELIMINARY ADJUSTMENTS
Refer to Figures 1 & 2..
a. Apply power to the AC controller.
b. The digital display (1-4) should read 0.0 when the motor is off.
c. Verify that the controller full-scale range matches the current transformer. Push and hold
the display toggle switch (1-10) to the right and turn the setpoint knob (1-9) fully clockwise.
The typical factory setting is 100.0A. To change this value, see section 6. MOTOR CUR-
RENT CALIBRATION (Span)
.
d. For automatic machine cycle, place the mode switch (1-11) to the left for the “Ready
“mode. When an enable signal is received, the "ENABLE" LED indicator (1-2) on the front
panel will light and activate the valve output. The red LED (1-3) for "valve" will blink. Adjust
the motor amps setpoint to desired motor amperage level.
e. Adjust the alarm bandwidth (2-7), typically 5A. By pushing the display switch (1-10) to
the left to exhibit the alarm bandwidth in the display, and turning the adjustment Pot to the
desired setting.
f. Adjust the alarm delay time (2-6) from 0-10 seconds. Typically 5 seconds.
Caution: The length of the motor amps current transformer wiring to the 50 mV
current shunt at terminals #16 and #18 must be less than 10 feet (3 M) of
16AWG wire, otherwise the digital display reading will show lower than actual
amps. Terminal #17 can be used to receive an input signal from motors with
variable-speed drives equipped with a 0-5Vdc output. This signal is used for
current/load monitoring. See section 14 for additional wiring information.