Welcome to The Hoist Guy's Blog, where our resident Hoist Guy Andrew T. Litecky shares his knowledge and experience of many years in the overhead material handling industry.
How are overhead cranes powered?
Electric overhead cranes, also known as bridge cranes, are typically powered by conductor bar, festooning or a cable reel. There are pros and cons of each type of electrification. In certain situations, overhead cranes are powered manually by push or hand geared options or with air power.
For overhead cranes powered by electricity, a device such as conductor bar, a festoon system or a cable reel will transfer the facility’s electrical power supply from a dedicated disconnect to the bridge, allowing it “travel” or move back and forth down the length of the runways. Meanwhile, the same electrification device provides power to the hoist for lifting and lowering. An operator controls both movements through either a pedant control that is wired into the system, or a radio remote control. To determine the best method for a crane system’s electrification, consider the supply of available power, the capacity of the system and the operating environment.
Conductor bar delivers power through an insulated system of four bars (L1, L2, L3, Ground) installed along the runway. It is cost-effective, easy to install and provides the best choice for electrifying long or low-headroom systems. This safe and durable method of electrification can operate on multiple crane systems, and it is easily expanded with more components when necessary. However, a disadvantage of conductor bar system is the sometimes frequent need to replace wear items like collector shoes. Also, a conductor bar system should never be used for hazardous location applications.
Cable festooning systems provide electricity through a system of lightweight flat or round cable connected to trolleys that carry it along a track or beam. They are reliable and safe for a variety of applications, including outdoor and high heat environments. Cable festooning is sometimes available in DIY “plug and play” configuration for easy installation on kit cranes, however, on the downside, cable festooning is not practical for systems with more than one bridge or runway.
Manually powered cranes operate by either pushing the load or by pulling a hand chain that drives a hand wheel. This method is typically for smaller cranes or for infrequently used maintenance cranes. A hand-geared crane generally maxes out at 5-tons capacity and about a 30 ft span.
In facilities that operate equipment with air-power, usually due to the combustible nature of production, air-powered overhead cranes are maintained. Air-powered cranes require 90 PSIG, 80- 10D SFand are available in capacities up to 30 Tons in short spans. Usually cable reels or festoon air hoses provide air-power to this type of overhead crane.
To determine the best power source for your crane system, consider factors such as the availability of power and safety considerations for your environment. When in doubt, contact a professional overhead crane installer.
Shupper-Brickle Equipment has provided bridge cranes, hoists, and engineering services since 1969. Contact us for more information on custom-built overhead cranes, comprehensive services and engineered solutions.