For rigid parts such as the base and end cover, as long as their shape and position tolerances and dimensions meet the requirements, problems are unlikely to occur after the entire machine is assembled. However, for other components, some quality issues may occur to varying degrees, such as damage to the windings during the assembly and transportation process, possible casting defects during the aluminum casting process, non-dimensional errors during assembly, and various problems such as uneven air gap between the stator and rotor after assembly, and some parts not being properly assembled. The purpose of inspection and testing is to measure the key parameters of the motor, evaluate the insulation reliability, check the no-load operation status of the motor, adjust the product to the optimal usage state, and promptly detect any fluctuations in the overall machine quality to prevent substandard products from being manufactured.
The inspection and test items for three-phase asynchronous motors are specified in the technical conditions of the product.
They mainly include:
● Measurement of insulation resistance between the windings and the ground, as well as between the windings; This test is conducted before other test items of the motor and special attention should be paid to the matching of the test instrument with the rated voltage of the motor.
● Measurement of the DC resistance of the windings; This test is carried out under the cold state of the motor and the deviation of the resistance during the test process should be identified based on the ambient temperature. Special attention should be paid to the accuracy of the resistance testing instrument and its suitability for the motor.
● Measurement of the open-circuit voltage of the rotor of the wound-rotor motor; This test mainly checks the winding ratio between the rotor and the stator of the motor. Under precise pressure application, the test value is very stable and consistent with the design value.
as the no-load test; this test mainly checks the performance of the rotor. When there are abnormal data, the material of the rotor aluminum, casting defects, etc. will be evaluated based on data such as current size and unevenness.
● The inter-turn insulation test and the withstand voltage test between the winding and the ground, as well as between phases; this is a complete test for the insulation performance of the motor winding.
● Mechanical inspection. This project is inspected and evaluated during the no-load test of the motor, mainly including the flexibility of the motor rotation, vibration, noise, and other abnormal mechanical problems. At this time, it is particularly emphasized that for motors with external fans, some motor manufacturers do not bring the fans during the inspection and test, but the mechanical performance of the fan must be checked when the entire machine is released, including the consistency of the no-load data with the no-load data from the type test for judgment.
Post time: Oct-17-2026