Load testing your overhead crane. How to load test your overheadcrane? Generally, load testing of is required by safety regulation and standards to make sure the overhead crane is installed right according the designing specifications. The owners and operators of overhead cranes should be pay attention to the following:
1> All overhead cranes, gantry cranes, suspension cranes, and jib cranes should be installed on designing specifications. 2> All overhead cranes, gantry cranes, suspension cranes and jib cranes should be proof tested once every four years after original proof testing. 3> All overhead cranes, gantry cranes, suspension cranes and jib cranes should be proof tested and operationally tested after modifications and repairs. 4> All the new and altered overhead cranes should be checked and tested with the following functions:
Hoisting and lowering.
Crane running or bridge travel.
Limit switches, locking and safety devices.
Overhead crane load testing project video
Before talking about the overhead crane load testing procedures, let’s see how the 10 ton overhead crane load testing video.
If you want to know more about the 10 ton overhead crane project, please check our crane project case study by clicking at Overhead Cranes Serving in Steel Coil Plant.
Overhead crane load testing
As for the load testing of overhead cranes, it should be bear in mind that the test loads shall not be more than the 125 % of the rated lifting capacity. And also all the load testing reports should be filed which can be accessed by the personnel who is in charge.
Pre-test procedures of overhead crane load testing
Check the overhead crane operator’s manual for the dos and don’ts, and the operational limitations.
Make sure the lifting gear to be used with the overhead crane in normal duties.
Make sure all lifting attachments are marketed with rating load visually.
Check the previous and periodic test and inspection notes, deficiency reports to make sure all the necessary corrections and repairs have been made.
Make sure all the safe working load of the overhead crane is clearly marked on the crane or on the tag on it.
Make sure the crane runway and runway structure were designed to support the cranes and loads in all authorized operation configurations.
Proper loads for the testing should be selected. A 25% rated load for minimum partial load testing, rated load testing, and a proof load around but not exceeding 125% of the rated load shall be used.
Check the overhead crane manufacturer’s instructions and limitation on load testing. The reeving configuration have to be bear in mind.
Proper ringing should be used for the load testing which must conforms to good rigging practice for lifting safety.
Safety measures should be used to prevent personnel or vehicles to intrude into the overhead crane operating region.
All the persons related to the overhead crane load testing including the overhead crane operator, the riggers and the hand signal man have to know the load testing procedures and how the overhead crane load testing conducted.
Inspect the overhead crane thoroughly, especially to the structural elements of the overhead cranes where the will be subjected to stress during the overhead crane load testing.
A visual inspection to the crane runway, track, powder conductors, collectors and switch gear should be conducted before the load testing.
Overhead crane Load testing
The overhead crane should be positioned on a stanchion or column of the runway with the trolley or electric hoist placed adjacent to the end of truck at the beginning of the overhead crane load testing to measure the deflection of the crane main girders and the runway girders at center span.
Lift the rated load up to a sufficient height to make sure each and every tooth of the lifting gear train is subjected to the rated load.
Lower the load to a height of 4 to 8 inches above the ground.
Measure the deflection. Traverse the bridge to mid span of the runway girder and measure the deflection. Traverse the trolley with rated load to mid span of the bridge and measure the deflection. Comparing the date you get with the specifications given by the overhead crane manufacturer.
With the holding brake in the released positon, start the load down slowly and then return the controller to the off position as the test load is lowering. The load controlling device should prevent the load from accelerating.
For overhead cranes with primary and secondary holding brakes and/ or eddy current or hoist eddy current or hoist dynamic load brakes visually observe that correct operation ensures control of the rated load.
For overhead cranes equipped with a hoist dynamic brake, eddy current brake, or regenerative brake, check lowering speeds against manufacturer’s specifications to ensure correct brake operation.
To ensure the safety of electric hoist unit in case of power failure during material handling operation of the overhead crane and electric hoist, lift the rated load to a convenient distance above the ground. Lower the load at high speed and, with the controller in the lowering position, disconnect the main power source and the load tested should stop lowering.
Test the overhead crane with 125% of rated load to achiever the proof load. Repeat items 2-1 through 2-7 and determine that during these operations all crane functions operate effectively.
The overhead crane should be operated at appropriate seeds to ensure the safety and the control of the load while handling the proof load.
Separate tests should be conducted for overhead cranes with double trolleys or hoists or more.
Operate the trolley or electric hoist with the proof load suspended from the hook trough the maximum operational range on the bridge. Observe that the trolley brakes are operating properly if appropriate and allow for load swing and coasting.
Operate the bridge with the proof load suspended from the hook as near as possible to the runway rail on each side through the maximum operational rang on the runway system to observe for any binding of bridge trucks and proper brake operation etc.
Test the brakes of bridge and trolley separately to make sure they can effectively stop in a distanced equal to 10 % of full load speed in feet per minute when traveling at full speed with full rated load.
The overhead crane runway with two or more cranes should be tested with all overhead cranes loaded with full capacity at same time. The crane runway deflection should be measured with the loads suspended as close as possible to the runway with the overhead cranes moving across the span between runway supports and compare the data to appropriate specifications.
Post overhead crane load testing
A thorough examination is needed to make sure the overhead crane has went through the tests satisfactorily.
Park the crane at the proper location for the convenience of use and relax all rigging and reeving to allow for inspection of the wire rope and reeving components.
Disconnect power and install a safety lock-out device before mounting the overhead crane.
Examine the overhead crane runway for structural damage or distortion, loose or damage fasteners, track alignment and secure attachment to the structural support.
Check the Electrical components of the overhead crane runway for deterioration and proper condition. Make sure the electric codes, wires, connections and enclosures in neatness, security.
Check and make sure all the sheaves, drums and wire rope from damage or excessive wear. Pay attention to the end fittings and anchor points for potential damage.
Check and make sure all the necessary guards and crane safety measures are installed. Make sure all shafts, couplings, an open gears that can be contacted by persons are properly guarded.
Make sure all the damages, deficiencies or corrections are marked accordingly.
Hoist the load blocks clear of personnel or obstructions. Make sure the wire rope is wound properly on the hoist drums. Open the main disconnect and leave the pendant, if any, in the designated location.
Fill in the report form and conduct an exit briefing if appropriate.