AEC Colortronic MSH Series 2039 - Manual (Page 29)

C Series Granulators Maintenance 29 of 53
5-7 Testing and Adjusting Zero Speed Sensor
The zero speed sensor detects the motion of the rotor assembly The sensor is interlocked to
the control circuits of the two machine jackscrews. If the rotor is turning, then the jackscrews
should not operate. If the jackscrews are able to operate before the rotor has come to a
complete stop, the zero speed sensor is not working.
The sensor has a green light, which is lit to indicate that the power to the sensor is on. There
is a red light on the sensor amplifier located in the control console. When the rotor is in
motion, the red light is lit. If the rotor is stopped, the red light is not lit.
Testing the Zero Speed Sensor
Use the following procedure to test the zero speed sensor:
1. Press the Start button to start the granulator.
2. When the machine reaches full speed, press the Stop button to stop the granulator.
3. Open the cutting chamber as directed in Section 3-6 on page 16.
4. Re-start the granulator.
5. When the machine reaches full speed, press the Stop button to stop the granulator.
6. Open the screen cradle as directed in Section 5-4 on page 23.
The jackscrews should NOT operate until the rotor has come to a complete stop. If the
jackscrews operate before the rotor stops, release the button on the selector switch and return
the switch to its Off position. Turn off and lock out the power and have a mechanic and
electrician adjust the sensor position.
Adjusting the Sensor Position
If the rotor is in motion and the red light is off, check the sensor position. If the green light is
off at all times, or if adjusting the sensor does not correct the sensor operation, then check the
control circuit logic between the jackscrews, the safety switches, the zero speed amplifier,
and the zero speed sensor. Refer the wiring diagram on page 50.
Use the following procedure to adjust the zero speed sensor position:
1. Disconnect and remove the sensor wire from the control console.
2. Remove the sensor from the bearing housing. Measure the length of the thread in the
tapped hole on the bearing housing where the sensor was mounted. Using this
dimension, measure from the end of the sensor and set the locknut at this point.
3. Thread the sensor into the hole and lock it in position. Turn the rotor assembly slowly
by hand to be sure that there is no interference between the sensor and the rotating
members. Complete the wiring between the sensor and the control console.