Precautions for Lifting and Operation of Electric Hoist

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When the electric hoist is hoisted, the lifting and operating methods are improper, and the electric hoist will cause the hanging object to swing and cause an accident. When the electric hoist is hoisted, the electric hoist should stop when the wire rope or chain is tightened.

The electric hoist should find the hook again according to the direction of the hook shaking. At the same time, the lifting worker should check whether the hoist is fastened; do not go too far when the electric hoist is hoisted. Severely, the lifting speed can be increased only after the hanging object is free from the obstacle; the hanging object raised by the electric hoist is not easy to be too high, and it is generally better to exceed the highest object of the safe passage by 0.5m.

When the electric hoist is operating. When conditions permit, it is best to hoist about 0.5m away from the ground, and the crane should stabilize the object behind the electric hoist, and run around the obstacle under the direction of the crane. When the electric hoist is running, do not intermittently. When running for a long distance, it is better to run the electric hoist for a long time.

When the electric hoist is running, the hoist should be stable. If the hoist swings or shakes, the hook should be stabilized while the hoist is running, and it should not be allowed to shake or swing.

Common Faults and Solutions of Electric Chain Hoist

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Electric Chain Hoist is a very common tool. Many customers improperly operate during use, which will cause many problems. The solutions are as follows:

1. The phase of the electrical line is connected incorrectly, which causes the phase protection function to start, so it cannot be operated.

Solution: swap the power cords of the two phases with each other.

2. The fuse of the power supply has blown or the non-fuse switch has tripped.

Solution: Check whether the current demand is met, replace a suitable fuse or restart the no-fuse switch.

3. The fuse of the control circuit is burned out.

Solution: Check and replace the correct fuse.

4. The power cord or control circuit wire is broken or not connected properly.

Solution: Repair or replace the broken or poorly contacted wire.

5. The voltage of the power supply is too low.

Solution: Measure whether the voltage value is lower than 10% of the standard power supply voltage.

6. The motor makes a sound, but it does not rotate.

Solution: Check whether the motor phase is correct-repair and perform insulation actions.

7. The emergency switch is pressed.

Solution: Confirm the reason for pressing the emergency switch.

8. Bad contactor.

Solution: Manually operate the hoist. If the electric chain hoist operates normally, it means that the control coil or wire has poor contact-find out the position of the poor contact and repair it; if the electric chain hoist still cannot be operated by manual operation, then It is necessary to check whether the main power supply is normal. If the main power supply does not have a title, the contactor is defective and cannot output normally, and the contactor needs to be replaced.

9. The coil of the contactor is short-circuited.

Solution: Replace the contactor.

Correct Connection of Crane Sling

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When hoisting, use the sling connection method correctly. The sling should be correctly placed and connected to the load in a safe way. The sling must be placed on the load so that the load can be balanced. The width of the sling should never be knotted or tied. The stitched part of the twisted sling can not be placed on the hook or lifting equipment, and always placed on the upright part of the sling, to prevent tag damage by staying away from the load, hook and locking angle.

Precautions for the use of multiple combination slings The evaluation of the ultimate working force of multiple combination slings is determined by the symmetry of the combined slings to bear the load, that is, when lifting, the branches of the slings are distributed symmetrically and evenly according to the design, with the same vertical angle . 3 Combination sling, if the branch cannot be uniformly loaded according to the design, and the maximum strength is on a branch, it will be the sum of the maximum bearing capacity of the adjacent branch at the design angle.

The same result is in the 4 combination sling, if it is not a rigid load , Will also be counted. Note: For rigid loads, most of the gravity may be borne by three or even two of them, and the remaining one only protects the balance of the load. When hoisting, the protective sling of the sling should be kept away from sharp edges, friction and wear, regardless of Whether it is away from the load or lifting equipment, the appropriate part of the sling should be strengthened and protected from sharp edges and wear. The necessary additional strengthening protection supplement is necessary.

Working Principle of Crane Electronic Scale

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Crane electronic scales use special-shaped resistive sensors. According to the principle of safety first and accuracy second, the sensors are installed through some mechanical parts processed. When the crane lifts heavy objects, all the pressure will be pressed to the sensor. Above, the sensor is deformed, and then the data is transmitted to the meter to display the data.

Safety Technical Requirements for Overload Limiter

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  1. The combined error of the mechanical overload limiter should not be greater than 8%, and the combined error of the electronic overload limiter should not be greater than 5%.
  2. When the load reaches 90% of the rated lifting capacity, a reminder alarm signal should be sent out.
  3. After the overload limiter is installed on the lifting machinery, it should be adjusted or calibrated according to its performance and accuracy. When the lifting capacity exceeds the rated lifting capacity, the lifting power source can be automatically cut off and a prohibitive alarm signal will be issued.
  4. Overload limiters should be installed for bridge type cranes, railway cranes and portal cranes; tower cranes, elevators and electric hoists can also be installed according to actual needs.

The Difference of Crane, Overhead crane and Trolley

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What is an overhead crane?
A crane is a complex machine that lifts, lowers and moves heavy or bulky loads. Cranes are equipped with components that provide the crane’s multi-directional mobility. A combination of the hoist, trolley and bridge motions provide full coverage of your factory floor.
What is a Hoist?
A hoist is a machine that performs a single task very well: lifting and lowering a load on a vertical plane. Hoists are situated on the primary horizontal beam of the crane, called the bridge girder. The hoist, when connected to the trolley, moves back and forth across the bridge girder. Chain hoists are excellent at lifting loads below 5 tons with little maintenance required, while Wire Rope Hoists are the optimal choice for 5 tons and above. Single-reeved hoists use a single piece of rope on the rope drum, while double-reeved hoists provide true vertical lift through the use of two ropes on a single drum. With wider diameter rope drums, minimum hook drift, or lateral movement of the hook, on a single-rived hoist can be achieved.
What is a Trolley?
The trolley is the mechanism that moves the hoist along the bridge girder of a crane. The hoist is moved horizontally along the top or underside of the bridge girder to position it above a load. There are three types of trolleys: low headroom, normal headroom and double girder trolley.

If you wanna the lifting equipment, but you do not know how to choose, welcome to contact us @ judy@cncranefactory.com

Winches vs Hoists

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For heavy-duty and demanding lifting applications, a strong case could be made for either a heavy lifting winch or a Wire Rope Hoist. Both pieces of equipment are able to lift high-capacity loads and are designed with consistently rigorous lifts in mind.

But as always, the day in and day out uses of your lifting equipment should drive which is the right-sized option for your application.

Today, we look at the different capabilities of winches and wire rope hoists to help you decide the right equipment for your next project.

When Should I Use A Winch Or A Wire Rope Hoist?

Both winches and wire rope hoists can suit heavy-lifting applications across many industries. But where a wire rope hoist can nimbly maneuver with a smaller footprint, winches are better suited for heavy lifting in process duty applications.

To better understand which lifting equipment is right for you, we’ll provide areas of consideration: capacity, duty cycle and lift application.

Capacity

Standard wire rope hoists will start to lose product range in terms of lift and capacity as they approach the maximum 80-ton capacity, due to the larger reeving and drum length needed for those capacities.

Yuantai Crane can provide hoists for that capacity. But if you also need an H4 duty cycle, we recommend using the winch product for your application. If the needs of your application reach into higher capacity ranges (80-160 tons), it will require a wire rope winch.

Not only do winch hoists include larger drums, but the reeving of the winch is also optimized for heavy use with a more condensed profile. Additionally, the orientation of the sheaves helps protect the wire rope from heavier use.

Duty Cycle

At lower capacities, however, the wire rope hoists are smaller and often less costly than winches. It’s at capacities of over 80 tons where the wire rope hoist cannot achieve the lift and duty cycle needed for the application. At capacities over 60 tons, the product lines overlap and the combination of capacity, lift and duty cycle often determine which product is best suited.

Winches offer a broader product portfolio in the higher capacity range, and they’re typically associated with higher duty cycle applications. This means that winches are prepared to function optimally even in applications like scrap yards, cement mills, paper mills, steel mills and other equally demanding lifting jobs.

As you can read in our article covering the classifications of duty cycles, selecting the right equipment for your duty cycle has a huge impact on the longevity of your equipment.

Lift Application

In the “Duty Cycle” section, we listed some applications that require high performance in harsh conditions. We often refer to these types of applications as “process duty.”

For process duty applications, we can compare what we know about wire rope hoists and winches to decide the best option – both pieces of lifting equipment can lift heavy loads. However, because of the higher duty cycle rating, the winch will require fewer part replacements and fewer opportunities for unexpected maintenance.

Where a wire rope hoist might perform well in this environment but at the wrong duty cycle for a few years, a winch at the right duty cycle may have a lifetime of 10 years or more. Additionally, winches often come with more standard features than wire rope hoists, where the needed features may be optional given the broader application range for wire rope hoists.

This discrepancy in the overall lifetime cost of ownership is a key consideration for facility managers looking to select new equipment.

A winch may also be combined with smaller wire rope hoists into a main and auxiliary hoist configuration on a single crane. This is advantageous for applications where the winch can be used for the highest capacity loads, and the lighter and faster wire rope hoists can accomplish the everyday lifting needed on the work floor. Additionally, having an auxiliary hoist means that you may have a back-up hoist to completely eliminate downtime.

For your next project, select a manufacturer who can create all the equipment you need in one package – this not only saves you on overhead and creates inroads for faster installation, but also service costs.

The Importance of Lubrication for Crane Wheel

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Even if you have perfectly aligned wheels and runway rails, the friction of crane flanges on runway rail eventually wears out the wheels and the rail.  Unfortunately, perfectly aligned wheels and rail rarely happens in real life; crane runway rail attached to steel building structures expands and contracts with temperature fluctuations causing alignment issues.

Crane wheels and crane rail replacement are two of the most expensive wearing components of a crane system.  In addition to the expense of replacement, rail and wheel replacement require that the crane and/or entire runway be placed out of commission during the work, which also creates the added expense of production loss if the work cannot be completed during a planned outage.

Spring-loaded lubrication sticks are mounted on each crane wheel with the lubrication applied to the wearing surfaces of the wheel flange.  A crane with 4 wheels will require 4 to 8 lube stick systems depending on the wear characteristics of the crane wheels.  The lubrication sticks are replaced approximately monthly on heavily used cranes during routine maintenance.   There is no worry about the lubrication getting on the railhead running surface and causing skidding as the lube is only on the flanges.

After installation of the dry lubrication systems, noticeable changes, visible by an inspectors’ eye, will occur on the existing wheel flanges in as little as a couple weeks on high use cranes.  The dull gray and gouged finish of the flanges transforms into one with a very smooth with a shiny “chrome-like finish”.  The measured rate of wear of the flange slows dramatically with the smoother and repaired mirror-like finish on the flange assisting to maintain a strong flange thickness. The flanges are not getting noticeably thinner. The matching side of the railhead is also being polished.

Before the lube sticks were installed the cranes generated a high-pitched sound due to abrasive and adhesive contact between the wheels and the rails as the crane bridges down the runway. This sound is often an intense screeching that is penetrating and distracting to workers.  The presence, and at other times absence, of some of the sounds make it apparent that there is some direct relationship of noise with outside climatic temperatures. The installation of dry lubrication significantly lessens this type of noise.

If you have problems with crane wheel or rail wear, Yuantai Crane can assist you in determining the cause and provide services including wheel or rail alignment as well as the installation of dry lubrication systems to help improve the performance of your cranes and hoists.

Why Hoist Wire Rope Failures

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A hoist wire rope is a machine in and of itself that requires proper selection, installation, and maintenance.  As a wire rope is used in a hoisting application, the individual wires move and allow the rope to bend around the drum and sheaves.  This movement causes friction and abrasive forces that require proper lubrication.  If selection, installation, operation, or maintenance is improper, the rope life will be shortened dramatically.  Even under the optimum conditions and usage, every wire rope used in a hoisting application will eventually fail. Therefore, routine periodic inspections, by a trained and qualified inspector must be employed to determine the condition of the wire rope so that replacement made before the rope fails.

When we look at wire rope wear and failure, there are numerous possible causes.   Possible causes include:

  • Abrasion Caused Failure
  • Core Protrusion
  • Corrosion Caused Failure
  • Cut or Shear Caused Failure
  • Fatigue Caused Failure
  • Tension Caused Failure (Overloading of Rope)