What are common bridge crane problems and how to solve your bridge crane prob...

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Bridge crane basic questions and solutions to ensure your bridge crane work more efficiently, safely and durably. 15 common problems on bridge crane control, hoisting system, crane braking, installation and braking, etc., and suggested solutions are presented for you.

Question 1: Why does Dongqi Crane use PLC on bridge crane?

Answer: PLC is the abbreviation of programmable logic controller. Its basic structure are composed of power, CPU, memory, input/output interface circuit, function module and communication module. PLC can change the form of relay-contacts control, and can make it adjustable for electric motors’ speed of every file, acceleration time and braking time according to practical conditions. PLC functions include calculating, controlling, programming, communicating, diagnosing, processing.

Because PLC has various advantages and can make heavy duty bridge overhead cranes more safety and convenient, Dongqi Enterprise apply PLC in bridge crane system. Its advantages are following.

• Convenient use, simple program
• Strong function, highly cost-effective
• Complete hardware, convenient use for customers, strong adaptability
• High reliability, strong anti-interference capability
• Little work for system’s design, installation and test
• Little work for maintenance and convenient maintenance.
  

Question 2: What’s the system of hoist bridge crane?

Answer: Electric hoist bridge crane mainly includes lifting mechanism, travelling mechanism (trolley travelling mechanism and bridge crane travelling mechanism) and rotating mechanism.

• First is lifting mechanism, it refers to electric hoist. It is composed of driving device (electric motor), braking device (brake), transmission device (reducer) and fetching rotating device (hook, grab, magnetic disc, and wire rope, chain, trolley, drum, sprocket and rope-guiding device).
• Second is horizontal travelling mechanism, it is trolley travelling mechanism. Travelling trolley is composed of electric motor, braking device (brake), transmission device (reducer) and trolley wheel device.
• Third is vertical travelling mechanism, it is bridge crane travelling mechanism. This mechanism includes driving mechanism (electric motor), braking device (brake), and transmission device (reducer) and bridge crane wheel device. The advantage of electric hoist bridge crane is that it adopts three-in-one driving device. It combines driving device (electric motor), braking device (brake) and transmission device (reducer) together. It is a compact and light driving device without shaft.
  

Question 3 : How do bridge cranes supply power ?

Answer: First is through flexible cable. The power of the lifting bridge crane is supplied by AC power system. Because the work of the bridge cranes is movable, the bridge crane and the power can’t be connected in fixed way. In general, the flexible cable is used to supply the power. When the bridge crane system and the trolley move on the tack, flexible cable can stretch and roll along the track. Second is through slide wire and electric brush. Three phase AC power is transported into cabin’s protection box through three main slide wires and electric brush, then transported to bridge crane system’s motor, electromagnet and AC control station through wire way. Third is through auxiliary slide wire and electric brush. This refers to the power supply of magnetic brake, trolley’s hoisting mechanism and trolley’s motor.

Double grider bridge crane main girder

Question 4 : What to do when the bridge crane trolley line is out of power ?

Answer: The reason is that electric brush climbs in the conductor, the brush wears seriously, conductor joint is not smooth, single connector is used, rail joint becomes loose. The correct way is to check whether the brush wears seriously, change electric brush, adjust the connecting joint, and adopt double-brush connector.

Question 5: What to do when the guiding rail is deformation, the collector doesn’t work?

Answer: The main reason is the temperature is too high, the distance between lifting racks is too long or loose. It is useful to adopt anti-heat plate partially, add sun shield outdoors, increase the number of trolley line lifting racks, correct the conductor and screw down the screws.

Question10: Why bridge crane system need buffers?

Answer: Three kinds of buffers are used widely, spring buffer, rubber buffer and hydraulic buffer. Spring buffer is reliable and convenient to maintain. Rubber buffer has simple structure. Hydraulic buffer can absorb large hitting energy and has no rebound effect. When limiting stopper of travelling extreme position or brake is in trouble, due to the inertia, the bridge crane system moving in the end or the trolley on the main girder, will hit against the stopper set in the position. But bridge crane buffer can absorb the travelling energy of bridge crane system or trolley and reduce impulsion. Buffers should be set between the bridge cranes travelling on the same track, or between the double trolleys on the same girder.

Question11: What is the anti-collision device on bridge cranes?

Answer: It mainly includes laser type, ultrasonic type, infrared type, electromagnetic type, all use the principle that light or radio wave travels, reflects and the distance can be measured. When two bridge cranes travels to pointed position, the bridge crane mechanism rings alarm bell and gives the stop command at the same time.

Question12: How does anti-deflection device protect bridge cranes?

It includes wire-rope type, cam type, chain wheel type and skew indicator and other automatic adjustable devices. When the bridge frame deflects to some degree, it can give signal to the operator and adjust itself automatically. When the bridge crane frame deflects seriously, it can cut the power automatically, stop the travelling mechanism and protect the safety.

Question13: What is the function of safety hook of bridge crane?

Answer: Safe hook is an important part of bridge crane. What are functions and types of safe hook?

Safety hook is mainly used for single girder bridge crane. Lifting material at one side of main girder, the material has a tilting torque against trolley, anti-tilting torque from vertical gauge wheel or horizontal gauge wheel can keep the trolley balance. But this kind of way can’t ensure the safety under the condition of cyclone, outside impact, wheel broken, crane maintenance and repair. Thus this bridge crane should be installed with safe hook. According to trolley and wheel, safe hook has different structures.

10 ton overhead crane for sale

What are common bridge crane problems and how to solve your bridge crane problems?