Friday, 30 January 2015

Common Causes Of Heavy Motor Fault

The motor as the equipment transfer the electrical energy into mechanical energy, playing an important role in the working process of the electric crane in normal operation. Then, what are the common causes of motor failures?

Motor consists of a stator frame, winding and insulation material, rotor, bearings on the both ends, end cover and other components, which is relatively simple. The causes of motor failures mainly include following ones. First, power off phase, voltage or frequency is wrong. Second is the problem of winding short circuit, open circuit and grounding. Third may be that bearings are dysfunctional. Fourth, bad heat dissipation caused by the dirty internal and external parts or the thick external paint may lead to the motor failure. In addition, bad mechanical equipment, long-term high load operation and the high ambient temperature also have influence on the motor’s performance.

In fact, if we regularly check carefully whether the motor condition is good or not, the vast majority of failure can be prevented and avoided. This is not only conducive to the protection of the normal operation of the motor, but also advantageous to reduce the loss of the company spare parts and repair costs.

Wednesday, 7 January 2015

Three Requirements For Motor Of Bridge Crane

Bridge crane follows the work rule of "start, brake, start, brake” in the work process for a long time, at the same time the power is in on and off state. And the lifting motor will carry different weight in the continuous reversal process. Therefore, for bridge crane motor, there are several requirements.

First, the bridge crane equipment must comply with the requirement of big starting torque and small lifting current. The reason is that the lifting motor usually starts with carrying heavy objects, and the starting torque has a certain effect on the hoisting performance.

Second, when loading and unloading, bridge crane should ensure the accurate placement. At present, we can use the electrical speed regulation method, through adjustment of the work speed for many times, to achieve the accurate placement of goods.

Third, the outer packing of bridge crane motor should be strengthened. The main idea is to strengthen mechanical structure and use high-grade heat insulation material on the outer packing. Because in the continuous operation of motor, it will be influenced by external mechanical impact, and meanwhile it will generate high energy, which requires good heat dissipation function of packaging.