| 摘要 |
<p>The watt-hour meter has two measurement modules (13,19) which are both connected to phase (L,L') and neutral (N) lines to perform measurements which are stored in separate memories (7,8) and compared by a microcontroller (1). The difference is stored in a ring memory (9). Either measurement may be displayed (4) and another display (5) is activated by any discrepancy attributable to ageing or a fault in either module. One module (13) may be a Ferraris counter with voltage and current coils (14,15) inducing short-circuit currents in an aluminium rotor (16). The other module (19) may be a purely electronic device contg. a Hall effect transducer (19') and a voltage-to-pulse frequency convertor (21).</p> |
