Reymsa HFC Series - Figure A-54: Motor Shaft Grounding Ring; Figure A-55: Motor Shaft Grounding Ring Path to Ground; Motor Shaft Grounding Ring

REYMSA COOLING TOWERS, INC.
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▪ Motor must be grounded to common earth ground with drive according to applicable standards.
▪ Rings should not operate over a keyway because the edges are very sharp.
CAUTION
▪ Care should be taken when handling the ring to prevent ber damage during installation.
▪ Do not use thread lock to secure the mounting screws as it may compromise the conductive
path to ground.
CAUTION
A.2.8.5. MOTOR SHAFT GROUNDING RING
Variable Frequency Drives can create stray currents that run along the shaft and discharge through the
motor bearings and bearings of coupled equipment — causing fusion craters, pitting, frosting and uting.
This problem can be solved grounding the motor shaft with the Shaft Grounding Ring (optional accessory,
see gure A-54) to provide a path of least resistance to ground and divert current away from the motor’s
bearings.
The Motor Shaft Grounding Ring conducts harmful shaft voltages away from the bearings to ground.
Voltage travels from the shaft, through the conductive microbers, through the housing of the ring, through
the hardware used to attach the ring to the motor, to ground (see gure A-55).
Path to Ground
Figure A-54: Motor Shaft Grounding Ring
Figure A-55: Motor Shaft Grounding Ring Path to Ground
Installation