Shaft Grounding Assembly FAQ

How long do Cutsforth™ grounding ropes last?

The life expectancy of the grounding ropes is approximately 12 months, but this depends greatly on the environmental factors present. The main contributors to decreased rope life are mechanical wear and electrical wear. Mechanical wear increases with factors like shaft surface speed, shaft surface roughness, and contaminants present on the shaft. Electrical wear mainly occurs on the grounding rope, and less on the metering rope, as the grounding rope carries most of the electrical load. For this reason, we typically find the metering rope lasts slightly longer than the grounding rope.

Is there enough contact on Cutsforth™ braided ropes to properly ground the shaft?

Yes, as the braided ropes wear the copper or silver ropes create hundreds of very small contact points to assist in the grounding process.

Where should the shaft ground wire terminate?

The purpose of the Shaft Grounding System is to electrically bond the shaft to the unit case immediately adjacent to the shaft to provide a safe and desirable path for the flow of shaft current, and to prevent the flow of shaft current through destructive paths, such as through bearings. Cutsforth™ requires the shaft ground termination to be the lower half of the generator, turbine, or coupling case, in the immediate vicinity of the Shaft Grounding Assembly. Examples of unacceptable grounding locations are structural steel, plant AC ground, or an existing grounding pad that requires an extended wire run to reach.

Can I change Cutsforth™ Shaft Grounding or metering ropes while the generator is online?

Yes, the Cutsforth™ Shaft Grounding System is designed to allow safe and easy online rope changes.

What is the minimum shaft diameter for Shaft Grounding Assembly installation?

The minimum shaft diameter on which the Shaft Grounding Assembly can be installed is 5 inches.

What is the minimum width requirement at the shaft grounding location for the Shaft Grounding Assembly?

The Cutsforth™ Shaft Grounding Assembly features a narrow profile design which only requires 1.5 inches of shaft space.

What is the temperature rating of the Shaft Grounding Assembly?

The Shaft Grounding Assembly is rated to 300°F (150°C). All voltage and current monitoring equipment is rated to 158°F (70°C).

Does Cutsforth™ Shaft Grounding work on large synchronous and induction motors?

Provided enough space is available on the shaft, the Cutsforth™ system will provide grounding.