It is easy to ignore the problem when using the motor
What problems are easy to ignore when using the motor
Why can't General Motors be used in plateau areas?
Altitude will have adverse effects on motor temperature, motor corona (high voltage motor) and DC motor commutation. Attention should be paid to the following three aspects:
(1) The higher the altitude, the greater the temperature rise of the motor, the smaller the output power. However, when the temperature decreases as the altitude increases to compensate for the effect of altitude on the temperature rise, the rated output power of the motor may remain unchanged.
(2) Anti corona measures should be taken when high voltage motors are used in plateau areas;
(3) The altitude is not conducive to the commutation of DC motor, so the carbon brush material should be selected.
Why does the motor produce shaft current?
The current in the motor's shaft bearing basic circuit is called shaft current.
Reason:
(1) Asymmetry of magnetic field;
(2) There are harmonics in the power supply current;
(3) Poor manufacturing and installation, uneven air gap due to eccentricity of rotor;
(4) There is a gap between two semicircles of the detachable stator core;
(5) There is no correct selection of the number of bricks to stack the stator core into a fan.
Adventure:
The surface of the motor bearing or ball is corroded to form a dot like micropore, which will reduce the operation performance of the bearing, increase the friction loss and heat generation, and eventually lead to the combustion of the bearing.
Prevention:
(1) Eliminate the pulsating flux and power harmonic (for example, add an AC reactor at the output side of the inverter);
(2) In the design of motor, the base of bearing box and sliding bearing is insulated, and the outer ring and end cover of rolling bearing are insulated.
3. Why should the motor not operate under light load?
When the motor operates under light load, it will cause:
(1) Low power factor of motor;
(2) Motor efficiency is low.
This will lead to waste of equipment and uneconomical operation.
Why can't the motor start in cold environment?
If the motor is too long in low temperature environment, it will:
(1) Motor insulation cracking;
(2) Bearing grease is frozen;
(3) Solder wire powder.
The motor shall be stored in a cold environment and the windings and bearings shall be checked before operation.
Why can't 60Hz motor use 50Hz power supply?
In the design of motor, silicon steel plate usually works in the saturation region of magnetization curve. When the power supply voltage is constant, reducing the frequency will increase the flux, and the excitation current will increase, which will lead to the increase of motor current and copper consumption, and ultimately lead to the increase of temperature. Engine. In severe cases, the motor may burn due to overheating of the coil.
Click soft launch. Can we save energy?
Soft start has limited energy-saving effect, but it can reduce the impact on the power grid, and can realize smooth start to protect the motor unit. According to the theory of energy saving, soft start not only does not save energy, but also increases energy consumption, and can reduce the starting current of the circuit and play a protective role.
Why is the leakage circuit breaker easy to trip when using frequency converter?
This is because the output waveform of the inverter contains high harmonics, and leakage current will be generated between the cable between the motor and the inverter and the motor. The leakage current is much greater than that of the converter, so this phenomenon will occur.