The motor is equipment exchanging electrical energy into mechanical energy. It uses the coil to produce a rotating magnetic field, and then function in the formation of magneto electric dynamic rotary torque. According to the using power the motor can be divided into DC motor and AC motor. And the direction of the force movement of the electrical wire in the magnetic field is relating to the direction of the current and the magnetic induction wire.
The use and control of the motor is very convenient, so it can meet various operation requirements. It can work with high work efficiency with no smoke, smell, pollution to the environment, and the noise is small. Generally, the output power of the motor can change with the speed, and there are many speed control methods, which also makes it possible for the motor to meet the different speed requirements of the different production machinery. From the point of energy consumption, there are two ways to control the speed. The first is to keep the constant input power and adjust the speed by changing energy consumption of the speed regulating device. The second is to adjust the speed by controlling the input power of the motor.
Tuesday, 25 November 2014
As a kind of commonly used machinery, crane plays an important role in industrial production. And nowadays the application of professional technology can greatly promote the development of crane.
Along with China's economic development, constantly updated modern science and technology, the expansion of industrial production scale and the raise of industry automaticity level, cranes are used in modern production process more and more widely, playing more and more important role and also facing increasingly high requirements. In the recent years, the extensive application of computer technology prompted many advanced design and interdisciplinary methods, and also prompted the modern manufacturing technology and testing technology to improve. The fierce international market competition is more and more dependent on technology competition, too. And all of these urge the technical performance of the crane to enter a brand-new development phase, and the crane is experiencing a great change. Chinese crane is entering the international market with an unprecedented speed and Chinese manufacturing industry faces opportunities and challenges of the new situation where the continuous development and innovation is very important.
Wednesday, 19 November 2014
After long-time use, each part of the crane will appear aging and wear conditions in different degree, including the crane engine. So, how to protect the engine of crane?
First, for the new crane or the crane after an overhaul, it is required to have a relatively long time as "running-in period", which is appropriate to be one to two months. During this critical period, the standard and suitable running in can make the various parts of the engine have a process of full contact, friction, accommodation and final finalization, so as to improve the ability of engine to adapt to the working conditions.
Second, pay much attention to the engine oil and cooling water. Not only ensure the supply, but also ensure the quality and performance of the engine oil and cooling water is in line with the requirements of the engine use. You should know that unqualified oil and cooling water will be easy to damage to various parts inside the engine.
Third, for each engine components, you should grasp each link of inspection, cleaning, and maintenance, so as to ensure that each part reaches clean, no loose, no defect, no dirt, and no shift phenomenon. If it is found that there are some faults of engine, you should excludes them at once, which is also one of the prerequisite of ensuring the safe operation of cranes.
Tuesday, 28 October 2014
During normal operation, there should be a certain gap between wheel flange and orbit of bridge crane, maximum clearance for the 30-40mm. But in exceptional circumstances, flange and rail side will be under the mutual extrusion and friction, which causes the occurrence of rail biting fault and then affect the safe operation of crane.
The harm of rail gnawing can be mainly in the following three aspects. The first is to reduce the service life of the wheel and rail. For the bridge crane with serious rail gnawing, the service life of the wheel is less than 1 year, or even only a few months, while the use time of track can be only 3-5 years, much shorter than that in the normal case.
The second is to increase the running resistance. According to the determination, the bridge crane with serious rail gnawing has much larger running resistance, which can reach 1.5-3.5 times bigger than the normal running resistance. And this may cause that the load of motor and transmission mechanism increase and even overload. Bridge crane with very serious rail gnawing may has the problem that wheel rim has deformation by extrusion, which may cause a derailment accident.
The third is to do an adverse effect on the building structure. Crane with rail gnawing can easily produce lateral load, which will lead to lateral displacement of rail and looseness of the rail fixing bolt. In addition, the lateral force to the roof truss by rail can seriously affect the tray and plant stress conditions, making the roof slab bridge local loosening or fracture.
Thursday, 9 October 2014
Before the use of electric hoist, you should do the following pre inspection work. First you should ensure that there are no obstacles or float in the operator’s walking range, line of sight, or the route of heavy things. Then you should test the conditions of every part. Hand control button should be accurate and sensitive. The motor and reducer should be with no abnormal noise. The brake should be sensitive and reliable. The upper and lower limit for action should be accurate and sensitive. The hook stop nut should be tightened securely. The hook should be flexible when it rotates in the horizontal and vertical direction. The hook pulley should be with flexible rotation. The wire rope should be with no cracks, but good lubrication. And it should be arranged on the drum in neat rows, with no signs of disengaged from the pulley groove, twirl, or folding buckle. Hanging tools should be with no abnormal phenomenon.
When using the electric hoist, you should ensure it doesn’t lift or unload heavy at one side, and prohibit the use of overload. The working environment temperature of electric hoist is in the range of - 25 ~ +40 C. Electric hoist is not applicable to places with full of corrosive gas or relative humidity above 85%. It cannot replace the explosion-proof hoist, and should not be used to lift molten metal or toxic, flammable and explosive articles.
After using the electric hoist, you should make sure that the power has been cut off. And daily maintenance of it is very important.
Wednesday, 24 September 2014
With the wide use of the electric chain hoist, it plays an important role in many places. And now this article will introduce how to install the electric chain hoist.
First you should install the chain box. Secondly, connect the power line. When connecting the power line, you must cut off the power in advance. At the same time, the ground wire should be well grounded, or when you touch any part of the operator or hoist chain, you are likely to feel the feeling of a shock. And then, lubricate the load chain of electric chain hoist. Lubrication of chain is one of the important factors affecting the service life of the load chain. Timely and effective lubrication of the load chain will ensure the effectively service life of the chain. Next, you should check the chain arrangement. For the electric chain with hoist multi row chain, you should ensure that the lower hook rack is not overturned. If there is turnover, you should restore the chain to the normal state, and ensure that welding mouth of the chain is arranged in rows. Do not hang load in the electric chain hoist whose chain is twisted. Finally, check the working voltage. Because the electric chain hoist leave factory with specified voltage the buyer requires or the higher voltage (only for dual voltage) like 230/460V, you need to check the wiring and confirm whether it meets the requirements of power supply voltage. If not, please refer to the manual corrections and ensure that it meets the working voltage.