1. Why can't general motors be used in plateau areas?
Altitude has adverse effects on motor temperature rise, motor corona (high voltage motor), and commutation of DC motor. The following three aspects should be noted:
(1) The higher the altitude, the higher the temperature rise of the motor, the lower the output power. However, when the temperature decreases with the increase of altitude enough to compensate for the influence of altitude on the temperature rise, the rated output power of the motor can remain unchanged;
(2) Anti-corona measures should be taken when the high-voltage motor is used in the plateau;
(3) The altitude is not good for the commutation of the DC motor, so pay attention to the selection of carbon brush materials.
2. Why is the motor not suitable for light load operation?
When the motor runs at light load, it will cause:
(1) The power factor of the motor is low;
(2) The motor efficiency is low.
(3) It will cause equipment waste and uneconomical operation.
3. Why can't the motor start in a cold environment?
Excessive use of the motor in a low-temperature environment will cause:
(1) Motor insulation cracks;
(2) Bearing grease freezes;
(3) The solder powder of the wire joint is powdered.
Therefore, the motor should be heated and stored in a cold environment, and the windings and bearings should be checked before running.
4. Why can't a 60Hz motor use a 50Hz power supply?
When the motor is designed, the silicon steel sheet generally works in the saturation region of the magnetization curve. When the power supply voltage is constant, reducing the frequency will increase the magnetic flux and the excitation current, resulting in an increase in the motor current and copper consumption, which will eventually lead to an increase in the temperature rise of the motor. In severe cases, the motor may be burned due to overheating of the coil.
5. Motor soft start
The soft-start has a limited energy-saving effect, but it can reduce the impact of start-up on the power grid, and can also achieve a smooth start to protect the motor unit. According to the theory of energy conservation, due to the addition of a relatively complex control circuit, a soft start not only does not save energy, and also increases energy consumption. But it can reduce the starting current of the circuit and play a protective role.