2. Why can't general motors be used in highland areas?
Altitude has an adverse effect on motor temperature rise, motor corona (high voltage motor) and DC motor commutation. The following three aspects should be noted:
(1) The altitude is high, the greater the temperature rise of the motor, the smaller the output power. But when the temperature rises with altitude, it is enough to compensate for the effect of altitude on temperature rise.
The rated output power of the motor can be unchanged;
(2) Anti-corona measures should be taken when the high-voltage motor is used in the plateau;
(3) Altitude is unfavorable for DC motor commutation, and attention should be paid to the selection of carbon brush materials.
3. Why should the motor not run at light load?
When the motor is running at light load, it will cause:
(1) The motor power factor is low;
(2) The motor efficiency is low.
It will cause equipment waste and uneconomical operation.
(1) The load is too large;
(2) lack of phase;
(3) blocked air ducts;
(4) The low speed running time is too long;
(5) The power supply harmonics are too large.
4. Why can't I start the motor in a cold environment at will?
The motor is too long in a low temperature environment and will:
(1) Motor insulation cracking;
(2) bearing grease freezing;
(3) Wire joint solder powder.
Therefore, the motor should be stored in a cold environment and the windings and bearings should be inspected before operation.
5. What are the reasons for the motor three-phase current imbalance?
(1) Three-phase voltage imbalance;
(2) The welding of a certain phase branch inside the motor is poor or the contact is not good;
(3) Short circuit between motor windings or short circuit to ground and phase;
(4) Wiring error.
6. Why can't a 60Hz motor be connected to a 50Hz power supply?
When designing the motor, the silicon steel sheet is generally operated in the saturation region of the magnetization curve. When the power supply voltage is constant, lowering the frequency will increase the magnetic flux, and the excitation current
The increase in flow leads to an increase in motor current and an increase in copper consumption, which ultimately leads to an increase in the temperature rise of the motor. In severe cases, the motor may be burnt due to overheating of the coil.
