How to Test Stepper Motor?

Quality Inspection of Stepper Motor:

First, under the condition of not connecting any equipment and wires, separate each wire of stepper motor, not touch the wires, turn the rotating shaft by hand, a good motor can rotate smoothly with a certain force and there is no jamming in the middle.

If there exists relatively jammed or completely unable to rotate in a certain position, it indicates that the motor is broken, which may be caused by bearing displacement, the grinding damage of the rotor and stator.

The damage should be caused by an excessive external force. A multimeter can be used to measure the impedance of two adjacent phases, which should be equal to the coil impedance given by the product.

If the equipment detects idling, it should be able to reach the specified speed. At the general speed, the noise emitted should be stable. Also, the load test is required. The specific test parameter needs to combine load torque and motor torque.

Second, Screw all the wires together. The larger the motor is, the greater the force required for screwing. In general, the stepper motor can not be screwed by manual at all. If invalid, the coil is broken.

For synchronous motor, in addition to the above methods, carefully observing its rotor is necessary. If there is a gap on the rotor which is not dislocated and small, the nail can not be embedded.

At this time, it is very easy to lose a step, so it is recommended to replace it. The fatal weakness of the servo motor is that it can not be knocked during loading and unloading because it is very easy to damage the encoder.

How to test stepper motor lose step:

In general, the stepper motor is divided into three-phase six-beat and five-phase ten beats.

Three Phase: three groups of windings, three lines. Six beats: three LEDs, cycle twice before returning to the starting status. Each time LED lights flash, the stepper motor will step by 0.1 wire.

Generally, the reason that the stepper motor’s step lose is the missing of one or two phases missing. That is to say, one of the lines is broken(as for the motor or the controller, it needs to be checked).

At this time, we can let the motor step by step, that is to say, each step moves forward with 0.1 wires. At each step, we shake the motor with our hands to see if it is in the locked status. If the LED is on but the motor is not in the locked status, there exist problems in this line.

Turn off all the power, disconnect the interface between the machine tool and the controller, find out the three lines, and then find out the 24V power line. Turn the multimeter to the resistance block, and measure the three lines one by one with a 24V line. Under normal conditions, there should be a resistance of about 8.5 ohms. If the resistance of any line is not the same as others, there may be a problem with that line.

If the testing result of the stepping motor is all right, we need to use the same method to detect the controller.