自動車診断におけるクランプ流量計の応用

バッテリ交換後（バッテリ交換前に他の故障による異常起動の有無を確認するためにも使用できます）、正常な起動状態に達していない場合は、起動電流のピークをチェックして故障を分析することができます。クランプ電流計はバッテリの厚い正極端子線に挟まなければならない（一般的にバッテリの正極端子には2本の線があり、1本は起動装置用、もう1本は電源用）。クランプ電流計を直流電流に設定し、ピーク測定モードにします。エンジンを起動し、クランプメータに表示されるピーク値を読み取り、自動車メーカーが指定したピーク値と比較します（モデルによってモーターの始動電流が異なるため）。

If it is lower than normal, please check in this order: battery positive cable contact, starting switch SW, switch conduction spring, battery negative cable; pay special attention to potential poor contacts in these areas. First set your clamp ammeter function switch to DCA file. Clamp it onto a wire from alternator to battery while paying attention to aligning its arrow direction with that of current flow direction indicated on meter head. Start engine and observe LCD display showing charging current; after normal operation starts, this value will gradually decline which indicates normal functioning. To determine whether alternator is functioning properly: duty cycle refers to percentage of positive half cycle within a pulse signal during each complete cycle. In engine electronic control system testing, various electromagnetic valves operate using pulse currents such as electronic carburetor mixed ratio control solenoid valve, idle solenoid valve, EGR solenoid valve, activated carbon tank control valve and distributor hall sensor detection. By comparing measured duty cycle values with standard values provided by automobile manufacturers respectively for each component mentioned above，it becomes easy to determine their operational status.