| 摘要 |
PURPOSE:To enable a highly accurate measurement of current feedable to an object to be measured by proper addition of an equation of an ambient temperature to an equation of an effective value current. CONSTITUTION:A main circuit current is picked up from a shunt SH of a DC motor DCM and inputted into a computer CPU through an insulation amplifier AMP. An ambient temperature detector TH is provided on the side of the DC motor DCM and an output thereof is inputted into the computer CPU through a converter TRD. Then, when the running time is set at T, the temperature rise limit value of the motor TM, the ambient temperature TS and the rated ambient temperature of the motor 40 deg.C, the CPU calculates equivalent continuous current (RMS current) I0 thermally equivalent to a varying current by the equation and indicated on a display CRT. Thus, when the ambient temperature TS is below 40 deg.C of the rated ambient temperature of the motor, a small value is displayed while when it is above 40 deg.C, a large value is displayed. |
