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Drum Vacuum System Over-current

Applies to
  • ThermoFlex

Description

 The drum vacuum shuts down due to an over-current error condition in the drum vacuum drive unit.

Causes

 Faulty drum vacuum drive

Solutions

 The drum vacuum system maintains a constant plate hold down force on the drum by varying the speed of the pump for different sizes of media. The greater the area of drum coverage, the lower the required pump speed. The current draw of the drum vacuum drive unit is fairly linear and increases with pump speed. Check the current draw behavior of the system by performing the following steps:
  1. Turn off power switch to inverter and remove the cover.
  2. CAUTION: HIGH VOLTAGE! - Use pliers to turn the switch to the ON position (90 degrees clockwise).
  3. The inverter should be in Stop mode (LED on STOP/RESET is lit), if not, press STOP/RESET button.
  4. Press LOCAL/REMOTE button such that the SEQ & REF LEDs are off (top right corner of display).
  5. Display should show "Frequency Ref" with a value in Hz below. If not, press the DSPL button until it does.
  6. Using the up/down arrow keys, change the Frequency Ref to the desired value.
  7. Press RUN.
  8. Press the DSPL button 2 times to get to "Output Amps" and record the value.
  9. Press the DSPL button 14 times to get back to "Frequency Ref".
  10. Using the up/down arrow keys, change the Frequency Ref to another value in the table below.
  11. Repeat steps 8-10 until all readings are taken.
  12. Press the STOP/RESET button to stop drive operation.
  13. Press the LOCAL/REMOTE button such that the SEQ & REF LEDs are on.
  14. Turn off the inverter using pliers to rotate the switch shaft 90 degrees counterclockwise and replace the cover.

Frequency Ref (equivalent RPM)

Output Amps

17 Hz  (1000)

 

33 Hz  (2000)

 

50 Hz  (3000)

 

67 Hz  (4000)

 

83 Hz  (5000)

 

100 Hz (6000)

 

 

Note: The Frequency Ref is the value to be set to get each Output Amps reading.

The current should increase linearly with the speed of the pump and the maximum current draw at 100Hz (6000rpm) should be 16-17Amps. If the system does not behave as described, the drum vacuum drive unit is faulty and should be replaced.

See also

 Drum vacuum drive parameter settings:Programming the Drum Vacuum Drive

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