| 摘要 |
PURPOSE:To set a frequency division ratio automatically when a pulse having frequency proportional to the power of a circuit to be measured is divided into pulses having countable frequency. CONSTITUTION:The electronic watthour meter comprises a V/F converting section 10 generating a frequency proportional to a power being inputted through a VT (instrument transformer) 4 and a CT (current transformer) 5 connected with a circuit 1 to be measured, a frequency dividing section 11 for diving an output pulse from the V/F converting section 10 into pulse having countable frequency, a section 12 for counting the output pulse from the frequency dividing section 11 and displaying power consumption of the circuit 1 to be measured, a VT ratio CT ratio setting section 16 receiving a VT ratio and a CT ratio in the form of a code through a switch, and a section 21 for setting a frequency division ratio at the frequency dividing section 11 at a constant time interval based on an input from the setting section 16. A frequency division ratio can be set by simply turning a switch to a code representative of a VT ratio and CT ratio. |
