| 摘要 |
A constant voltage is applied across a variable capacitor (503) coupled to a rotating shaft (S). As the shaft (S) rotates, the capacitance of the variable capacitor (503) changes - causing a displacement current to flow into and out of the variable capacitor (503) in response to shaft (S) rotation. A current-to-voltage converter (501, 502, 504) converts the displacement current to a voltage level responsive to instantaneous shaft velocity. The resulting shaft rotation analyzer is so sensitive that it can detect ''signatures'' of shaft (S) rotation (e.g., shaft speed variations attributable to electric motor commutator contact, cogging variations, and the like). Various techniques and structures are used to reduce ''fringing effects'', increase the linearity of the capacitance change, and reduce variations in capacitance due to shaft axial movement. |
