Trial Weight Calculator

Calculation of trial weight mass for rotor balancing

M_t = M_r × K_supp × K_vib / (R_t × (N/100)²)

where:
M_t - trial weight mass, g
M_r - rotor mass
K_supp - support stiffness coefficient (1-5)
K_vib - vibration level coefficient
R_t - trial weight installation radius
N - rotor speed, rpm

Rotor mass (M_r)

Trial weight installation radius (R_t)

Rotor speed (N), rpm

Support stiffness coefficient (K_supp)

1.0

Vibration level, mm/sec

Enter value

K_vib = 1.0

✓ Calculation Result

Calculator Description

This calculator is designed to calculate the trial weight mass required for the dynamic rotor balancing procedure. Proper selection of trial weight mass is critical for successful balancing.

How it works

The calculator uses an empirical formula that takes into account rotor mass, weight installation radius, rotation speed, support stiffness, and vibration level.

Support stiffness coefficient (K_supp)

1.0 - Very soft supports (rubber dampers)
2.0-3.0 - Medium stiffness (standard bearings)
4.0-5.0 - Rigid supports (massive foundation)

Vibration levels and coefficients

Low (up to 5 mm/sec) - K_vib = 0.5
Normal (5-10 mm/sec) - K_vib = 1.0
Elevated (10-20 mm/sec) - K_vib = 1.5
High (20-40 mm/sec) - K_vib = 2.0
Very high (>40 mm/sec) - K_vib = 2.5

Important! The trial weight mass is selected so that its installation causes a noticeable change (>20-30 degrees) in phase and (20-30%) in vibration amplitude.

Two-plane balancing procedure

First run (without weights) - initial vibration is measured
Second run - trial weight is installed in the first plane
Third run - trial weight is removed from the first plane and installed in the second plane

Critical!

Correction weights must be installed at the same radius as trial weights!
After each trial run, trial weights are removed!
Correction weight is installed at the calculated angle from the trial weight position in the direction of rotor rotation!