First, why does the Nanyang AC motor generate shaft current?
The current in the shaft-bearing-basic circuit of a motor is called the shaft current.
Causes of shaft current:
(1) the asymmetry of the magnetic field;
(2) There are harmonics in the power supply current;
(3) The manufacturing and installation are not good, and the air gap is uneven due to the eccentricity of the rotor;
(4) There is a gap between the two semicircles of the removable stator core;
(5) The wattage of the fan-shaped stator core is incorrectly selected.
The surface of the Nanyang AC motor bearing or ball is corroded, forming formed micro-holes, which will reduce the running performance of the bearing, increase friction loss and heat, and eventually cause the bearing to burn.
(1) Eliminate pulsating magnetic flux and power harmonics (such as adding an Nanyang AC reactor to the output side of the inverter);
(2) When designing an Nanyang AC motor, the base of the bearing housing and sliding bearing are insulated, and the outer ring and end cover of the rolling bearing are insulated.
Second, why can't ordinary Nanyang AC motors be used in plateau areas?
Altitude can adversely affect motor temperature rise and motor corona (high voltage motor). The following three aspects should be noted:
(1) The higher the altitude, the greater the temperature rise of the motor and the smaller the output power. However, when temperature rises with altitude, it is sufficient to compensate for the effect of altitude on temperature rise.
The rated output power of the Nanyang AC motor can remain unchanged;
(2) When high voltage motors are used in plateau areas, anti-corona measures should be taken;
(3) Altitude is not conducive to AC Direction Motor commutation. Pay attention to the choice of carbon brush material.