On schematic page W7V6JEC, we apply voltage to the A-D card at 1MTA82 pin 4 is DC common, Pin 5 is -12vdc, pin 6 is +12vdc, and pin 3 is +5 vdc. On MTA83 pins 1 to 4 we measure the voltage from the accelerometer. It is important that the resting voltage be 2.50 vdc.

If the voltage is not in the expected range of the accelerometer, we turn on output K0 on the A-D card. This output is wired between MTA85 pins 1 to 4. If this is true, we limit the inverter to a minimum extract speed. This is done by turning on an output on the inverter as soon as the minimum extract speed is reached on the inverter frequency. This coupled with the output for the accelerometer being out of specification causes an input to M6-6 to be made and it will stop the inverter from any further speed advance by turning on CRATM at M3-1. This energizes CRATL which makes an input to the inverter at S7 that the out of balance is too large.

If the voltage off the accelerometer exceeds the threshold (set by jumpers J1, J2, J3 or J4 or some combination of those at MTA84 pins 1, 2, 3, or 4), we turn on output K3 on the A-D card. This output is wired across MTA85 pins 8 to 9. This makes an input at M6-6. The processor turns on CRATM at M3-1, which energizes CRATL. This makes an input at S7 on the inverter to stop any further acceleration of the machine.

When setting the Threshold voltage you want the machine to reach threshold till the machine is a close as possible to max extract speed. If the max frequency is 153 hertz, you would want it to reach threshold prior to 153, but as close as possible to 153 hertz. The test weight is the maximum out of balance the machine can have and still close to max extract. Anything greater than this would trip the threshold voltage sooner and the machine would stop acceleration at a lower frequency.


CSH 12 Apr 13