| 摘要 |
A current measurement device comprises a current transformer 12 and a switch 16 that switches the output of the current sensor to either an energy storage device 18 such as a capacitor or to a current measurement circuit 20. When a measurement is not being made, the switch charges the capacitor to store energy to power the measurement circuit. The measurement circuit may include a wireless transmitter 22 and the current transformer may be of the type that clamps around a cable 32. In another aspect (figures 3 and 4 â not shown), the current sensor may be used in part of a monitoring system that measures energy consumption of appliances connected to a grid. If the appliance energy consumption is above a threshold then a control signal may switch off the appliance or alert the user. The monitoring system may be used to select the best tariff for a consumer.
|
