PUMP IMPELLER BALANCING SPEED - DYNAMIC 2-PLANE 1

[msaah]

Hi all,

We recently ran into issue where the impeller we are supposedly balancing is yielding different unbalance mass when we spun it at different speeds, which makes sense given the sensitivity threshold and vibration.

Although, it is a common knowledge on obtaining the tolerance for unbalance using the G standards from ISO, I am having hard time finding an equation that can provide me the optimal speed to spin the impeller on the rotor, to give the most accurate readings.

Any advice on this matter is greatly appreciated. FYI, We are using a Schenk CAB700H, H30 MODEL.

thank you

 

[BEMPE16524]

From my references:

To achieve accurate balance readings for your impeller, determining the optimal speed to spin it is crucial. The speed at which you spin the impeller should ideally be based on both the rotor's operational speed and the characteristics of your balancing machine.

Key Factors to Consider:
Resonant Frequency Avoidance: Avoid speeds near the rotor's natural frequencies, as resonance can amplify vibrations and distort the measurement. Your machine might already have sensors to detect resonance conditions, but manually verifying this is helpful.

Sensitivity and Accuracy: Higher speeds typically provide better sensitivity to unbalance because centrifugal forces increase. However, this also amplifies noise and may exceed the machine’s operational limits. The goal is to find a speed that balances sensitivity with stability.

ISO G-Standard: You can determine an optimal balancing speed by considering the G (balance quality) grade as per ISO standards. For rotors, this speed is often tied to the operational speed, but it doesn’t always need to match exactly.

Given that you are using a Schenk CAB700H, consulting the machine’s manual for its calibration constant would help. However, in practice, trial and error along with manufacturer guidelines will help fine-tune this speed.

Additional Tips:
Incremental Testing: Start at a lower speed, gradually increase it while observing the vibration and unbalance data. Look for a stable reading.
Multiple Runs: Compare results at different speeds. The most consistent results usually indicate the optimal speed.
By applying these principles, you can find a speed that gives reliable and repeatable results while balancing your impeller.

R.Efendy