Grasp the special matters in the motor vibration test and judgment
The national standard number for measurement, evaluation and limit of motor vibration is GB10068. This standard is applicable to three-phase AC and DC motors with rated output power below 50MW and rated speed of 600-3600r/min. For vertical motors and flange mounted motors, this standard is only applicable to motors that can be measured in a free-floating state. However, this standard does not apply to motors installed at the operating site, three-phase commutator motors, vertical hydro-generators, permanent magnet generators, and series-excited DC motors. Ms. Participate in sharing this content with you.
Special emphasis on vibration measurement
● The regulation of the measured value. The vibration measurement value is the vibration displacement (double vibration) at the motor bearing, the effective value of the vibration speed, and the vibration acceleration.
● Measurement method. For rigid installations, the motor should be fastened to the unit and avoid additional vibration due to uneven tightening forces and uneven mounting planes. For V1 vertical motors, the motor should be mounted on a dedicated gantry; for B5 horizontal motors, when the motor is small, it can be placed directly on the sponge pad. When the motor is large, it should be placed in a suitable V-type. On the bracket, a sponge or rubber should be added between the bracket and the motor to reduce additional vibration.
● Half key installation. Insert the appropriate half key into the keyway. When using the "full height half length" half key, place the half key in the axial middle position of the keyway. The half key is then tightened onto the shaft with a special nylon or steel sleeve. The fixing must be reliable to prevent the high-speed rotation and the safety accident.
● Motor running status. Unless otherwise specified, the motor should be operated under no-load, no-load conditions. (1) For AC motors, the rated frequency and rated voltage shall be applied. (2) For DC motors, the rated armature voltage and the appropriate field current should be applied to bring the motor to the rated speed. (3) For multi-speed motors, they should be operated and measured at each speed. (4) For the speed-regulating motor, the measurement should be made within the entire speed regulation range or the speed at which the maximum vibration value is found by the test. (5) For the generator, it can be operated at no-load under the rated speed by the motor; if it cannot be operated by the motor, the speed should reach the rated value and run at no load under the drag of other power.
