Archive for November, 2016

The overheating of the press motor is a common and complex problem

Monday, November 14th, 2016

Motor is the power of the motor, punch if damaged, will affect the work, but also in extreme cases lead to injury to workers. The most common faults in the use of the motor are fever and burning.

Motor overheating is a common and complex problems, including overheating winding, rotor core and bearing overheating, overheating. Overheating for many reasons, each part of the treatment were resolved and eliminated.

Cause A stator, stator winding overheat winding resistance, current will heat, motor, performance is basically the same, only the current heating. The current does not exceed the rated current, the motor winding is not overheated, the current exceeds the rated current, winding overheating, resulting in increased current winding overheating reasons. In the motor winding overheating, cause analysis from the power supply, motor and load these three aspects.

1 power supply

The voltage is too low.

The voltage is too high.

Phase integration, resulting in single-phase operation.

Knife switches, fuses, connectors in the false contact, resulting in single-phase intermittent operation.

2 motor

The phase winding wire, resulting in single-phase operation.

Winding short circuit fault.

Reduce the motor rotor speed caused by mechanical failure, cage induced current and stator current increases.

Wrong wiring, such as connecting to a star angle connection error, the motor idling is not overheating, overheating when full load. If the angular error of the star is connected, even the air may overheat. The reverse of a phase winding will overheat. Noise at the same time.

3 load

The equipment is not complete, a small horse-drawn cart.

Increased load operation, such as thresher, grinding machine feed too much, centrifugal pump flow level increase or decrease the water level, axial flow pump, lift increase.

It is a mechanical failure that raises the motor traction or sticks to a fixed electric engine overheating.

Two core, the core motor overheating is a composite pressure of silicon steel sheet insulation from each other, resulting in core overheating:

Incorrect installation of the rotor or serious bearing wear, so that the rotor and the stator core. This phenomenon is known as the “sweep chamber” or “rub the core” of rural electricians in general.

The voltage is so high that the magnetic flux, the loss of energy and the heat generated increase at the core.

Silicon steel sheet between the insulation damage, the short circuit between the chip, eddy current loss increases.

Stator winding short-circuit fault or incorrect wiring.

Bearing three, bearing at high temperature overheating is due to friction ball and outer ring generation, overheating reasons:

Lack of oil.

The excess oil or oil is too thick.

The oil is too dirty, the other small particles or oil quality is not good.

Bearing bending.

Bearing wear or other problems.

Motor shaft correction is not good or the belt is too tight, so that bearing pressure increases, friction.

The end cap and bearing are not properly installed. In addition to causing overheating of the above, we should also note that the thermal conditions do not cause the motor to overheat.

The following reasons heat is not good:

Ambient temperature is too high.
Motor internal dust too much, affecting heat dissipation.

Fan damage or volume reduction reaction of the fans.

In the long-term punch motor, often there will be a variety of failures: between the connector and the reducer transmission torque, connecting the flange surface serious wear and tear, gap connection transmission torque increases, resulting in a smooth; motor shaft bearing damage caused by wear and tear , Keyway shaft bearings such as wear. The problem of occurrence, repair of machine repair or gold-plated traditional methods, but they have certain shortcomings. High temperature thermal stress, can not completely eliminate welding repair, easy bending or fracture; and brushing coating thickness limit, easy to peel, and the two methods used in the metal, can not change the “hard hard”, all stress Of the combined effect, will cause wear and tear. In response to the above problems, the contemporary Western countries, polymer composite materials repair methods, and more applications Meijia technology products, with strong adhesion, compressive strength and excellent comprehensive performance. Polymer materials in repair applications, not only the thickness of the welding heat stress layer, repair is not restricted, the franchise of metal materials and products are not, can absorb shock and vibration equipment, to avoid the possibility of wear and extend the service life of parts , For enterprises to save a lot of time and create enormous economic value.