Related Products:

EGMA-004, EGMA-005, EGMA-006, EGMA-007, EGMA-008, EGMA-013, EGMA-015, EGMA-016, EGMA-019

Related Documents:

EZDP-2020 and EZDP-2038


Technical information


Premium Monitoring System, Technical Specifications, Shaft Voltage, Cable Length


Descriptions of overall system performance with measurements and a graph to demonstrate the impact of signal cable length on shaft voltage in the Premium Monitoring System.

Overall System Performance

The measurements below show overall system performance with the Premium Monitoring System completely assembled for the following lengths of signal cable of the type referenced in Cable Gauge, Length, and Signal Quality:

  • 10 ft (3 m)

  • 20 ft (6 m)

  • 40 ft (12 m)

  • 60 ft (18 m)

The graph below does not account for interference caused by the installed environment, but it does represent what can be expected when adding together the variables in the system’s signal acquisition chain. The shortest cable length possible is always our strongest recommendation.

The scope AC coupling cutoff takes place between 10 and 20 Hz depending somewhat on the length of cable installed. The response curve is fairly flat through the vast majority of the spectrum of expected signals that will take place on your generator. Amplification does ramp up slightly on signals occurring at approximately 100 kHz. At 300 to 500 kHz, deviation begins to appear most dramatically depending on cable length. Here it is evident that best overall signal acquisition is obtained by planning a SGA-to-Premium Monitoring System conduit length of 20 ft or less. At 40 ft, the plant needs to decide if they will tolerate the loss that takes place at the upper spectrum . The 60 ft signal cable is not recommended, showing a rapid drop off starting at around 4 MHz.


Note that the ground current and shaft voltage sensing equipment can capture events that typical hand-held voltage and amperage meters would likely miss. This may result in initial readings appearing higher than the plant is used to seeing depending on the measurement tools and methods used in the past. Also, like an oscilloscope with a long lead, even when the generator is offline it is likely you will see readings above 0 due to environmental noise and sensor noise. 

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