Crane & Hoist Electrification and Conductors
CRANE 1 realizes the importance of every crane system meeting the production needs of the customer while minimizing overall maintenance costs. We understand that every project has unique challenges that require special considerations for the components to ensure both proper functionality and longevity.
The electrification system is one of the most important elements of a crane and hoisting system. The electrification system at a minimum will provide a single or three-phase power supply required by the traveling crane and hoist equipment, but may also carry control signals that operate contactors, limit switches, and other functions. With the many different types and brands of electrification being available, it can be difficult for a user to determine which electrification system is best is a specific application.
Mainline – Bridge Crane Runway or Monorail Electrification
The mainline runway or monorail electrification systems consists of rigid construction conductor bars, cable festoon system, or cable reel that are mounted on the runway and deliver the mainline power along the length of the runway or monorail track.
Conductor Bar
Conductor bars consist of a rigid conductor bar constructed from formed galvanized steel, copper, or stainless steel depending on the application and amperage requirement. The conductor bar is generally covered with a nonconductive plastic cover on three sides with an opening for the collector shoe that carries the power from the mainline to the bridge or trolley.
The conductor bar is generally suspended on the runway structure or bridge from brackets, but there are also conductor bars styles that can be mounted flush to the web of the runway or bridge beam. Conductor bar arrangements for three-phase power consist of 3 individual conductors for phased power and one for a ground. The ground bar must be installed with a different color cover, (generally green) than the power conductors.
When conductor bar is used in longer systems, expansion assemblies must be used to keep the bar straight when temperature changes dramatically and multiple power feeds may be required to reduce amperage drop. The main areas of maintenance on conductor bar systems are the collector assemblies and shoes as they are the normal wear and tear item.
CRANE 1 most commonly supplies conductor bar from Insul-8, Wampler/Conductix, and Magnetek
Advantages:
- No length restrictions
- Low cost in standard applications
- Low maintenance.
- Can be used on monorail systems on both curves and switches
Disadvantages:
- The opening at the bottom allows for a potential shock hazard
- Cannot be used in an explosive environment
Festoon System
Festoon systems consist of a c-track suspended from brackets mounted on the bridge or runway structure. The c-track system runs parallel to the crane bridge beam, monorail or crane runway. Small trolleys running on the c-track carry looped festoon conductors that provide power and control functions. Generally, the festoon cables are flat cables with multiple conductors to match the number of conductors required of the application.
Multiple cables are stacked so that power and control currents do not run in the same cable jacket. The limitation to the ultimate length of a festoon system is the loop depth used, required wire size, and space limitation of the festoon trolley stack-up on the fixed end. Festoon systems are economical, can be very heavy duty, and are ideal for carrying many control signals at the same time.
Festoons are the standard electrification system used across the girder of a bridge crane and are often used for monorails and jib crane applications. Festoon systems are a good solution for runways in hazardous environments where open conductors are not an option.
When specifying a c-track system,, you can upgrade the standard galvanized track and trolleys to stainless steel as well as upgrade trolley wheels from plastic to steel wheels. Additionally, the flat cables can be furnished with different jacket materials for high heat or difficult environments.
Advantages:
- Relative low cost
- Use in corrosive and explosion proof applications
Disadvantage:
- Ultimate length is limited by wire size and festoon stack-up capability.
Cable Reel
A cable reel is essentially an electrical cord that pays-out and retracts into a spring-loaded reel. They can be used for shorter power and control applications when the use of a festoon system is precluded due to potential interferences with the equipment by the cable loops or rigid supporting c track of a festoon system. Cable reels may also be the best option where open conductors are not allowed, and the hoist trolley travels around a short monorail system with curves and switches provided that the cord has free access to travel with the hoist without encountering obstructions.
Advantages:
- Can be used in horizontal and vertical applications to provide both power and control to cranes, hoists, and devices suspended on the hoist hook.
- Totally closed conductor limiting risk of shock.
- Hazardous or wet environments
Disadvantages
- Limited travel length
- Maintenance issues with the high use
- Relative high cost per vs festoon and conductor bar
If you are considering a new crane system, or are looking to upgrade or replace an existing conductor system on your crane or runway; contact one of our experts at your local CRANE l for helpful advice and competitive pricing on both materials and installation.
