| 摘要 |
<p>PURPOSE:To enable safe and rapid measurement of each value only by manipulating switches, by incorporating a voltmeter, an ammeter and a phase-difference meter in a portable case body and by making them conduct simultaneous digital display of measured values for an arbitrary phase. CONSTITUTION:A voltmeter 4, an ammeter 7 and a phase-difference meter 8 all of which made digital display, three-phase four-wire type voltage input terminals R, S, T and N, a current input terminal I, and switches 3 and 5 for each phase of voltage and current inputs are arranged on the same panel of a portable case body, while a current range shifting switch 6 designed so that a current circuit to be measured is not opened even when shifting is made during measurement of the current is provided. In addition, an end resistance on the secondary side of a current transformer for meters is made to be of a very small value, while a resistance attenuator on the secondary side of the current transformer for meters is made to have a resistance value of about 200kilohm, and thereby the shifting by the shifting switch is made possible without opening or short-circuiting the circuit to be measured.</p> |
