YOKOGAWA 2042, User Manual

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2. 測定レンジの切換
(1) 測定に際し，いずれの場合でも電圧端子は，回路電圧に近いレン
ジを用い，負荷大電流が未知の場合，最初電流測定端子に接続し
電源スイッチを入れます。
電圧，電流レンジとも端子切換で電圧レンジは，2 倍定格比 (2:1)，
電流レンジは，5 倍定格比 (5:1) です。
(2) 電流回路が変流器の二次側に接続されている状態でレンジ切換を
行う場合，
変流器の二次が開路にならぬようご注意ください。
変流器に二次巻線短絡鍵があれば，これをまず閉路してレンジ
切換えを行ってください。
二次巻線短絡鍵がない場合には，電源を切るとか，電流端子の接
続を換えるときにとりはずされるべき電流端子の配線をそのまま
にしておいて，その配線の一端を必要とする電流端子に接続して
それから不要の電流端子の配線をはずすようにしてください。
2. Range Selection
(1) For an accurate measurement, use the voltage terminal whose rated
value is closer to the circuit voltage. If the load current is unknown,
connect the circuit to the current terminal rated largest initially.
Then apply power to the circuit.
Both voltage and current ranges are changed by selecting terminals.
The ratio of the voltage ranges is 2:1.
The ratio of current ranges is 5:1.
(2) When using a current transformer, be sure not to open the secondary
circuit of the CT when changing the current range.
If the CT is provided with a switch to short the secondary circuit,
close the circuit using the switch before changing the measuring
range. If such a switch is not provided, you can either switch off the
power source before proceeding with the change or you can follow the
alternative wiring method for changing the range.
In this method, you use another leadwire to connect between the circuit
terminal to which the existing leadwire is connected and the CT current
terminal to be used for the new measuring range. Leave the existing
leadwire connected all during this procedure. Once the new terminal is
connected, you can disconnect the existing leadwire from the original
CT current terminal that will no longer be used.