| 摘要 |
<p>An analogue and numerical indication of rotational speed is obtained from a tachometric system utilising a three phase alternator to drive a three phase motor. Motor output provides a pointer drive and a numerical totaliser drive. A three phase alternator (1) coupled (2) to shaft under measurement drives three phase motor (3) autosynchronously. Motor drives measurement magnet (4) which in turn drives a non-magnetic disc (5) whose axle shaft (7) provides drive for a pointer (8) via a spiral spring (6). The pointer provides an indication against a dial (9) while gearing (10, 11) from a shaft (7) provides drive for counter drums (14) for numerical display.</p> |
