Overhead travelling cranes

[Saut]

I would like to know what is the standard of the braking system on an overhead crane. Some suppliers tell me it's a standard to use electromagnetic braking instead of the conventional hydraulic type. Is this true? and what are the advantages of using the electromagnetic type?

 

[plasgears]

As in automation equipment, the electrical version is most preferred. Hydraulic is complicated and troubled with leakage, etc.

 

[kenvlach]

Check with Crane Manufacturers Association of America for standards on overhead bridge cranes:

http://www.mhia.org/psc/PSC_Products_Cranes.cfm

ISO has a big section on cranes:

http://www.iso.ch/iso/en/CatalogueListPage.CatalogueList?ICS1=53&ICS2=20&ICS3=20

ISO Catalogue
53.020.20
Cranes
Including mobile cranes, tower cranes, jib cranes, bridge cranes, etc.
ISO 4301-2:1985 Lifting appliances -- Classification -- Part 2: Mobile cranes
ISO 4301-3:1993 Cranes -- Classification -- Part 3: Tower cranes
ISO 4301-4:1989 Cranes and related equipment -- Classification -- Part 4: Jib cranes
ISO 4301-5:1991 Cranes -- Classification -- Part 5: Overhead travelling and portal bridge cranes
ISO 4302:1981 Cranes -- Wind load assessment
ISO 4304:1987 Cranes other than mobile and floating cranes -- General requirements for stability
ISO 4305:1991 Mobile cranes -- Determination of stability
ISO 4306-1:1990 Cranes -- Vocabulary -- Part 1: General
ISO 4306-2:1994 Cranes -- Vocabulary -- Part 2: Mobile cranes
ISO 4306-3:1991 Cranes -- Vocabulary -- Part 3: Tower cranes
ISO 4310:1981 Cranes -- Test code and procedures
ISO 7296-1:1991 Cranes -- Graphic symbols -- Part 1: General
ISO 7296-1:1991/ Amd 1:1996
ISO 7296-2:1996 Cranes -- Graphical symbols -- Part 2: Mobile cranes
ISO 7752-2:1985 Lifting appliances -- Controls -- Layout and characteristics -- Part 2: Basic arrangement and requirements for mobile cranes
ISO 7752-2:1985/Add 1:1986
ISO 7752-3:1993 Cranes -- Controls -- Layout and characteristics -- Part 3: Tower cranes
ISO 7752-4:1989 Cranes -- Controls -- Layout and characteristics -- Part 4: Jib cranes
ISO 7752-5:1985 Lifting appliances -- Controls -- Layout and characteristics -- Part 5: Overhead travelling cranes and portal bridge cranes
ISO 8087:1985 Mobile cranes -- Drum and sheave sizes
ISO 8306:1985 Cranes -- Overhead travelling cranes and portal bridge cranes -- Tolerances for cranes and tracks
ISO 8566-1:1992 Cranes -- Cabins -- Part 1: General
ISO 8566-2:1995 Cranes -- Cabins -- Part 2: Mobile cranes
ISO 8566-3:1992 Cranes -- Cabins -- Part 3: Tower cranes
ISO 8566-4:1998 Cranes -- Cabins -- Part 4: Jib cranes
ISO 8566-5:1992 Cranes -- Cabins -- Part 5: Overhead travelling and portal bridge cranes
ISO 8686-1:1989 Cranes -- Design principles for loads and load combinations -- Part 1: General
ISO 8686-3:1998 Cranes -- Design principles for loads and load combinations -- Part 3: Tower cranes
ISO 8686-5:1992 Cranes -- Design principles for loads and load combinations -- Part 5: Overhead travelling and portal bridge cranes
ISO 9373:1989 Cranes and related equipment -- Accuracy requirements for measuring parameters during testing
ISO 9374-1:1989 Cranes -- Information to be provided -- Part 1: General
ISO 9374-3:2002 Cranes -- Information to be provided for enquiries, orders, offers and supply -- Part 3: Tower cranes
ISO 9374-4:1989 Cranes -- Information to be provided -- Part 4: Jib cranes
ISO 9374-5:1991 Cranes -- Information to be provided -- Part 5: Overhead travelling cranes and portal bridge cranes
ISO 9926-1:1990 Cranes -- Training of drivers -- Part 1: General
ISO 9927-1:1994 Cranes -- Inspections -- Part 1: General
ISO 9928-1:1990 Cranes -- Crane driving manual -- Part 1: General
ISO 9942-1:1994 Cranes -- Information labels -- Part 1: General
ISO 9942-3:1999 Cranes -- Information labels -- Part 3: Tower cranes
ISO 10245-1:1994 Cranes -- Limiting and indicating devices -- Part 1: General
ISO 10245-2:1994 Cranes -- Limiting and indicating devices -- Part 2: Mobile cranes
ISO 10245-3:1999 Cranes -- Limiting and indicating devices -- Part 3: Tower cranes
ISO 10245-5:1995 Cranes -- Limiting and indicating devices -- Part 5: Overhead travelling and portal bridge cranes
ISO 10972-1:1998 Cranes -- Requirements for mechanisms -- Part 1: General
ISO 10973:1995 Cranes -- Spare parts manual
ISO 11630:1997 Cranes -- Measurement of wheel alignment
ISO 11660-1:1999 Cranes -- Access, guards and restraints -- Part 1: General
ISO 11660-2:1994 Cranes -- Access, guards and restraints -- Part 2: Mobile cranes
ISO 11660-3:1999 Cranes -- Access, guards and restraints -- Part 3: Tower cranes
ISO 11660-5:2001 Cranes -- Access, guards and restraints -- Part 5: Bridge and gantry cranes
ISO 11661:1998 Mobile cranes -- Presentation of rated capacity charts
ISO 11662-1:1995 Mobile cranes -- Experimental determination of crane performance -- Part 1: Tipping loads and radii
ISO 11994:1997 Cranes -- Availability -- Vocabulary
ISO 12210-1:1998 Cranes -- Anchoring devices for in-service and out-of-service conditions -- Part 1: General
ISO 12210-4:1998 Cranes -- Anchoring devices for in-service and out-of-service conditions -- Part 4: Jib cranes
ISO 12210-4:1998/Cor 1:2000
ISO 12478-1:1997 Cranes -- Maintenance manual -- Part 1: General
ISO 12480-1:1997 Cranes -- Safe use -- Part 1: General
ISO 12482-1:1995 Cranes -- Condition monitoring -- Part 1: General
ISO 12485:1998 Tower cranes -- Stability requirements
ISO 13200:1995 Cranes -- Safety signs and hazard pictorials -- General principles
ISO 15513:2000 Cranes -- Competency requirements for crane drivers (operators), slingers, signallers and assessors
ISO/TS 15696:2000 Cranes -- List of equivalent terms







Cranes
Including mobile cranes, tower cranes, jib cranes, bridge cranes, etc.

 

[Saut]

Thanks plasgears, but what if there's a loss of electrical supply, then wouldn't the electromagnetic type be more dangerous, and what if preventing the leak is not a problem, like minimise the use of joints? Is the industry moving away from hydraulic braking?

 

[birdstruck]

I would agree that an electric system is preferable due to the common power system lower cost. A typical top running system would have two clamps (attached to the end truck) which sandwich the rail from the sides. The brakes which I have seen most frequently are usually designed to be locked in the absense of electrical power and mechanically actuated to release the rail when the drive motor is energized. Therefore, safety is not dimenished. Incidentally, many cranes are geared so that the backdriving of the system is prohibited, reducing the need for any braking system at all.

 

[SERVOCAM]

I have worked on large overhead crane systems - 40 - 60 ton. Used servo motors on the system with electro-mechanical brakes. They machine is used in "Alternative Fuel" so the system needed to have a way to manually move everything, therefore the brakes had a manual disenguage as well.

So in this case, if there was a power failure, there was a cam switch on the brake that would override and unlock the brake.
Cameron Anderson - Sales & Applications Engineer
Aerotech, Inc. -

http://www.aerotech.com

"Dedicated to the Science of Motion"

 

[automatic2]

Electrical brake is standard on bridge style overhead cranes. When the motor is energized, the brake is released. The brake is adjustable to prevent sudden stops.

Mobile equipment use hydraulics almost exclusively with the exception of clutched direct drives found typically in larger excavating equipment. Anit fall valves (pilot operated checks) are used to prevent free fall/wheel conditions in hydraulics.

In a fixed location crane/hoist, electircal approach is less costly, both in capital and ongoing operations. Up to certian power requirements, where the size of motors may become prohibitively expensive compared to clutched systems. Hydraulics imply mobility.

I had worded in a steel mill years ago that had a large bridge crane hoist laddles of molten steel up to the pouring floor, about 8 stories high. On one occasion the operator had just taken a pour from the arc furnace and was up at the second story level when the hoist coupling sheared. The laddle free fell and sank neatly into the dirt floor without so much a splash.