Wed Oct 27 2021

Imbalance alarm

The customer is experiencing an unbalanced condition. They have ran the same process for a long time and says the centrifuge is running steady. Is there a sensor adjustment for sensitivity? The customer is experiencing an unbalanced condition. They have ran the same process for a long time and says the centrifuge is running steady. Is there a sensor adjustment for sensitivity?

   RE: Centrifuge Report Post
Fri Oct 29 2021Reply from Chris S
Chris S

I am not familiar with this particular model, but looking through the manual there have been 3 different styles of imbalance detectors; a mechanical arm, a vibration detecting device, and a trip arm.  The adjustment is different depending on which style of detector your centrifuge has.  Assuming you have checked the usual suspects that the centrifuge is level, rotor is tight, no debris in the buckets, etc.

Vibration Detector

1. Remove the lower front panel. The imbalance detector is located in the upper left corner of the centrifuge, attached to the frame.

2. Remove the cover plate from the imbalance detector.

3. Install an H-6000A Rotor (or equivalent) with buckets onto the drive spindle. Make sure all buckets swing freely.

4. Place a 150 gram weight into one bucket and accelerate to 1000 ~~~~ the imbalance detector should trip and shut the centrifuge down. If adjustment is needed, turn the adjust~ng screw. Next, remove the 150 gram weight and place a 65 gram weight into one bucket. Accelerate to 1000 rpm. The imbalance detector should not trip. Adjust the adjusting screw if necessary. Repeat this step until the imbalance detector does not trip with the 65 gram weight in place.

5. Reinstall the imbalance detector cover plate removed in step 2.

6. Reinstall the lower front panel.

Mechanical Arm

Remove the lower front panel and verify that there is a 2.4 mm (3/32 inch) gap between the imbalance detector and the motor housing. If not, adjust by bending the detector arm as needed. Reinstall the lower front panel.

Microswitch/Trip Arm

1. Set the POWER switch to OFF and unplug the centrifuge power cord.

2. Remove the gyro cover seal to gain access to the imbalance trip arm mounted to the gyro drive housing.

3. Loosen the locknut on the adjusting screw located at the tip of the imbalance trip arm.

4. Slowly turn the adjusting screw clockwise until the sw~tch contacts are closed. (Listen for the switch to click.)

5. Note the position of the screw slot. then turn the adjusting screw 2-1/2 turns counterclockwise. Tighten the locknut on the adjusting screw.

6. Replace the gyro cover seal.

Assuming you have checked the usual suspects that the centrifuge is level, rotor is tight, no debris in the buckets, etc.


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Fri Oct 29 2021Reply from EGPLUS
avatar placemark

Chris, I appreciate this info. I will let you know what I find


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