| 摘要 |
<p>In an active shaft ground system for maintaining a rotating shaft (4) of a machine substantially at ground potential, which system includes a circuit coupled to the shaft (4) for monitoring the voltage on the shaft (4) relative to ground and a brush (6) coupled to the circuit and contacting the shaft (4) for conducting to the shaft (4) a compensating current having an amplitude and polarity adjusted for maintaining the shaft voltage substantially at ground potential, there is provided shaft condition detection circuitry (18,20,24,26,28,34,36) coupled to the circuit for monitoring the voltage on the shaft (4) relative to ground and the current flowing between the brush (6) and the shaft (4) and for producing a fault indication when the voltage on the shaft (4) relative to ground is outside of a selected range at the same time that the current flowing through the brush (6) is substantially equal to zero. The detection circuitry permits reliable monitoring of brush bounce and distinguishes between that condition and brush rub.</p> |
