How to predict the risk resistance of a motor

In the actual operation of the motor, the stability of different operating conditions is not the same, some motors in the process of operation may encounter overload, voltage instability and other unexpected conditions, in order to ensure the safety of the motor operation, in the design process of the motor will be part of the parameters to retain a certain margin, and in the test phase of the motor to carry out the necessary verification.

The ability of the motor to resist abnormal conditions needs to be verified and evaluated by some specific test items. Such as resistance to short-time over-voltage, occasional over-current and short-time over-torque on the electrical performance of the windings, short-time overspeed on the mechanical properties of the motor.

For the capability test items for abnormal operating conditions, they will be specified in the general standard requirements of the motor, and the specific test items needed will be clearly required or described in the corresponding technical conditions of the motor.

Occasional overcurrent test is to evaluate whether there is any bad phenomenon of insulation aging in the windings of the motor after the specified size of current in the specified time. For different types of motors, the test conditions are different, the size of the test current is selected according to 1.5 times the rated current, but the overcurrent experience time varies, specifically in accordance with the provisions of the technical conditions of the motor product.

In the actual application, can also be in accordance with the specific operating conditions of the product, the test conditions put forward special requirements, these may go through the process, need to be guaranteed in the design program and manufacturing process of the motor.

Short-time over-torque test is under the condition of rated voltage and rated frequency of the motor, let the motor withstand the rated torque of a certain number of times the actual torque, the time in accordance with the 15-second control, the motor speed should not appear in the process of the test suddenly decelerated, for synchronous motors should not appear to be out of step, the test should not appear after the motor of the key components of the distortion of the deformation of the undesirable phenomena. The test should be in accordance with different motor categories, combined with the motor’s technical conditions and reasonable choice of parameters to prevent the motor from causing adverse consequences.

Short-time over-voltage test in the no-load state of the motor, most of the motor in the no-load test when the test, generally apply 1.3 times the rated voltage, lasted 1 minute, the motor should not appear after the test insulation aging, turn-to-turn, phase-to-phase and ground and other poor quality problems.