High-frequency ground straps

Paul Boughton

AEGIS High-Frequency Ground Straps ensure a very low-impedance path to ground for the high-frequency currents generated by VFD-driven motors and systems.

Non-zero impedances within a ground system can give rise to transient voltages and ground system currents that can travel along motor shafts and damage motor bearings.

The high-frequency grounding straps bond the frames of motors and other system components to equalise their earth potential and eliminate ground loops.

AEGIS HF Ground Straps are engineered for the lowest possible impedance to the high-frequency currents generated by VFDs. These 12-inch long flat-braided, tinned copper straps are designed with a circular hole on one end for easy installation around the foot mounting screw of NEMA- or IEC-frame motors and a ring terminal on the opposite end.  Custom lengths and terminations are available upon request.

Variable frequency drives (also known as VFDs, variable speed drives, or inverters) can save 30% or more in energy costs, but they can also damage motors. VFDs induce high-frequency voltages on the shafts of the motors they control — voltages that can discharge through motor bearings, destroying them in as little as three months and damaging coupled equipment.

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