Is the cast iron motor strong or not

The influence of contact resistance of cast aluminum rotor on motor performance

The aluminum conductor and iron core of the cast aluminum rotor are tightly attached together, and the low contact resistance generates a considerable lateral current, especially when the rotor is skewed, which has a significant impact on the stray losses and operating performance of the motor. Ms., today we will have a brief discussion on the contact resistance of cast aluminum rotors.

Measurement of Contact Resistance

The contact between the cage bars of the cast aluminum rotor and the rotor slot wall is very tight. When the rotor surface is precision machined, the cutting pressure of the tool further compresses the aluminum conductor and iron core in the slot, and the contact resistance between them is very small.

Measurement of contact resistance between rotor core and squirrel cage: Introduce direct current between the end ring of the squirrel cage and the shaft, and measure the average voltage drop between the squirrel cage and the core. At this point, the contact resistance can be calculated using the following formula:

Rc=c l Q2Uav/I………………(1)

In equation (1):

Rc - Contact resistance (Ω· mm2);

I - Direct current through the rotor (A);

Uav - average voltage drop between rotor cage and iron core (V);

Q2- Number of rotor slots;

L - length of rotor iron core (mm);

C - The circumference of the rotor cage section, i.e. the circumference of the rotor slot (mm).