Electrical Systems & Power Distribution
Conductor bars, festoon systems, grounding, electrical enclosures, lockout/tagout, and electrified runway safety.
- Identify conductor bar and festoon cable systems used to power overhead cranes
- Explain proper grounding requirements and electrical enclosure safety
- Describe lockout/tagout procedures for crane maintenance
- Identify pendant cable damage response and festoon tow trolley function
Lesson 1
Conductor Bars & Festoon Cable Systems
How Overhead Cranes Get Power
Overhead cranes need electrical power delivered to the bridge as it travels along the runway and to the trolley as it travels along the bridge. Two primary systems deliver this power: conductor bars and festoon cable systems.
Conductor Bars
The main runway conductor type is a conductor bar/festoon cable system. Conductor bars (also called bus bars) are rigid metal rails mounted along the runway. A collector shoe attached to the crane bridge slides along the conductor bar to maintain electrical contact as the crane moves.
Conductor Bars
Rigid metal rails along runway
Collector shoes maintain contact
Common on longer runways
Enclosed or open designs
Festoon Systems
Flexible cables on carrier trolleys
Cable loop travels with crane
Common on bridge trolley power
Also used on shorter runways
Festoon Systems
The function of a festoon system is to carry power/control cables along the bridge or trolley. Festoon cables are flexible electrical cables suspended from trolleys that ride on a rail or track. As the crane or trolley moves, the festoon cables extend and retract in loops.
Festoon Tow Trolley
A festoon tow trolley is a device that carries festoon cable along the bridge/trolley. These small trolleys ride on a dedicated track and are connected to the moving crane or trolley. As the crane moves, it pulls the tow trolley, which in turn carries the festoon cable loops along the span.
Exam Distinction
A festoon system carries power/control cables. A festoon tow trolley is the device that carries those cables along the bridge or trolley track.
The main runway conductor types are conductor bar and festoon cable systems. The festoon system carries power/control cables along the bridge/trolley. A festoon tow trolley carries the festoon cable along the track.