Electronics AC-24 - Manual (Page 3)

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1. PRODUCT DESCRIPTION
The Model AC-24 Amperage Controller is used with wheel-type shot peening and blast clean-
ing machines 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 indica-
tions of motor amps. A 0-10 Volt dc output signal proportional to motor amps is available for
remote indication or strip-chart recorder. High and low alarms are set to bracket the re-
quested amperage setting. The alarm bandwidth is adjustable from the front panel. Either lo-
cal (front panel) or remote 0-10 Vdc setpoint commands may be used.
2. THEORY OF OPERATION
The desired motor amps setpoint is compared with the actual motor amperage and a servo
command signal is sent to the MagnaValve to permit shot to flow and to achieve desired mo-
tor amps. If the desired amperage is not achieved within an adjustable time period, then a
high/low alarm relay will be triggered. The MagnaValve uses permanent magnets to hold the
shot and electro-magnets to cancel the magnetic field. When power is applied to electro-
magnets the shot is free to flow.
3. LOCATION OF ADJUSTMENTS
For location of adjustments see Figures 1 and 2. Numbers in parenthesis (figure-balloon) rep-
resent figure number and balloon call-out number. For example, digital display is (1-3), mean-
ing figure 1 and balloon number 3. Notice that the yellow buttons also require you to use the
▼ or ▲ buttons to change the display readings. The black buttons act alone to change the
status of a function.
4. PRELIMINARY ADJUSTMENTS
A. Apply 24Vdc power to AC controller.
B. If the 24Vdc power is less than 23Vdc or greater than 26Vdc then the all of the front panel
LEDs will flash.
C. The digital display (1-1) should read 0.0 when the motor is off.
D. Verify that the Controller full-scale range matches the current transformer (or the range of
the motor speed control if using the 10Vdc input option). Push and hold the display range
button (2-21) to show the full-scale range. Typical factory setting is 100.0 amps for full
scale display. To change this value continue to hold (2-28 or 29) while you push (1-12) to
increase or (1-11) to decrease the full-scale range.
E. For automatic machine cycle, push the mode button (2-20) until the ready mode led (1-6)
is on.
F. When an “Enable” signal is received, the “ON” LED indicator (1-7) on the front panel will
light and activate the valve output. The red bar graph LED (2-13) will display the magni-
tude of the servo command signal sent to the MagnaValve.
G. Adjust the motor amps setpoint (1-8) and ▼ or ▲ to desired motor amperage level.
H. Select the alarm band mode, either percentage of setpoint (PT) or percentage of full-scale
(FS) by pushing (2-16)
Caution: The motor amps current transformer wiring to the 50 mOhm current
shunt at terminals #5 and #7 must be less than 10 feet (3 M) of 16AWG wire,
otherwise the digital display reading will show lower than actual amps.
Terminal #6 can be used for signal input for motors with variable- speed
drives that have a 0-5Vdc output for current or load monitor. See section 14
for additional wiring information.