According to the requirement of rotor speed test during the dynamic balancing process
a computer assistant testing(CAT) method which utilizes PC and Hall sensor to test the rotor speed on-line is introduced.The hardware structure and software design of this system are discussed and the performance of the system is evaluated.At last the error and stability of system are verified at 1 000
1
2 000 r/min whitch is the common speed of motorcycle.Results show that the test system conform with the design requests.