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In industrial and agricultural production, oil pump motors are widely used as power units. In the process of use, there will be various small faults. If it is not processed in time, it will cause the motor to run abnormally. Dalan Motor Xiaobian summarizes the oil pump motor faults that maintenance engineers often encounter, for your reference.
First, why does the motor have shaft current?
The shaft of the motor - the housing - the current in the base circuit is called the shaft current.
Reasons for the onset of shaft current:
(1) Asymmetry of the magnetic field;
(2) There are harmonics in the supply current;
(3) The production and installation are not good, because the rotor is deformed to form uneven air gap;
(4) There is a gap between the two semicircles of the detachable stator core;
(5) The number of tiles having the stator cores stacked in a fan shape is not suitable.
Damage: The surface of the motor bearing or the ball is eroded, and the shape of the micro-holes is made, which deteriorates the bearing operation function, and the collision loss and heat are added, and the bearing is burned after all.
Prevent: (1) Eliminate pulsating magnetic flux and power supply harmonics (such as installing an AC reactor on the output side of the inverter); (2) Insulate the bearing housing and base of the sliding bearing, the outer ring and end of the rolling bearing when designing the motor Cover insulation.
Second, why is the general motor not used in the plateau?
The degree of improvement has an effect on the temperature rise of the motor, the commutation of the motor corona (high voltage motor) and the DC motor.
The following three aspects should be noted:
(1) The sea is raised, the greater the temperature rise of the motor, the smaller the output power. However, when the temperature decreases with increasing altitude to compensate for the effect of altitude on temperature rise, the additional output power of the motor can be unchanged;
(2) The high-voltage motor should adopt the anti-corona method when it is used in the plateau;
(3) Sea height improvement For DC motor commutation, it is necessary to pay attention to the selection of carbon brush data.
Third, why should the motor not be lightly loaded?
When the motor is lightly loaded, it will form:
(1) The motor power factor is low;
(2) The motor efficiency is low.
Equipment will be formed and the operation will be uneconomical.
4. 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 punctured, the falling frequency will increase the magnetic flux, and the excitation current will be added, resulting in the addition of motor current and the addition of 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. What operations do you need to do before the motor is put into operation?
(1) Measure the insulation resistance between the stator and winding phases and the winding to ground. The insulation resistance R should be satisfactory as follows: R>Un/(1000+P/1000)(MΩ)Un: Motor winding extra voltage (V)P: Motor power (KW) About Un=380V motor, R>0.38MΩ. If the insulation resistance is low, it can be: a: the motor is dry for 2~3h during no-load operation; b: the low-voltage alternating current with 10% extra voltage is connected to the winding or the three-phase winding is connected in series and then dried by direct current, and the current is kept at 50%. Additional current; c: heated by a fan or heated by a heating element.
(2) Finishing the motor.
(3) Replace the bearing smooth grease.
6. Why can't I start the motor in an icy environment at will?
The motor is too long in a low temperature environment and will:
(1) Motor insulation cracking;
(2) The bearing is smooth and frozen;
(3) Wire joint solder powder.
Therefore, the motor should be heated and stored in an ice-cold environment, and the windings and bearings should be viewed before operation.
What do I need to do before starting the motor?
(1) Measure the insulation resistance (for low-voltage motors should not be lower than 0.5MΩ);
(2) Measure the power supply voltage. Check if the motor wiring is correct and the power supply voltage meets the requirements;
(3) Check if the starting equipment is outstanding;
(4) Check if the fuse is suitable;
(5) Check the grounding of the motor, whether the zero connection is outstanding;
(6) Check if the transmission equipment has shortcomings;
(7) Check if the motor environment is suitable, and remove flammable materials and other sundries.
----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant
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