Polyphase electrical signal measuring apparatus
AssigneeRefac Electronics Corporation
InventorPhilip Danby
Life of this patent
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Abstract
Apparatus is provided for simultaneously measuring and displaying voltage, current and frequency in a polyphase alternating current system. The apparatus is operable in either a line-to-line or a line-to-neutral measuring mode without rewiring the apparatus to the measured system. A logic circuit is selectively operated to connect the appropriate voltage lines associated with each phase of the system to the apparatus and LEDs associated with each phase light to indicate the phase selected for measurement. Multi-digit seven segment LED displays are provided for simultaneously indicating the voltage, current and frequency measured.
Claims11
Apparatus for simulataneously measuring a magnitude and displaying a numerical representation of the measured magnitude for a voltage, current and frequency in a polyphase alternating current system, said apparatus comprising:
- means for coupling said polyphase alternating current system to said apparatus;
- means for selectively conditioning said apparatus to operate in either a line-to-line or a line-to-neutral measuring mode;
- means for selectively choosing for measurement any one phase of said polyphase system coupled to said apparatus;
- first display means for indication a magnitude of a measured voltage associated with a selected phase;
- second display means for indicating a magnitude of a measured current associated with a selected phase;
- third display means for indicating a measured frequency associated with a selected phase;
- first circuit means for sensing a voltage associated with a selected phase wherein said voltage is sensed line-to-line or line-to-neutral in accordance with said selected measuring mode, said first circuit means including first other circuit means for transforming said sensed voltage into a digital signal representative of the voltage magnitude of said sensed voltage to drive said first display means;
- second circuit means for sensing a current associated with a selected phase wherein said current is sensed line-to-line or line-to-neutral in accordance with said selected measuring mode, said second circuit meand including second other cirucit means for transforming said sensed current into a digital signal representative of the current magnitude of said sensed current to drive said second display means, and
- third circuit means for sensing a frequency associated with a selected phase, said third circuit means including other circuit means for transforming said sensed frequency signal into a digital signal representative of said sensed frequency signal to drive said third display means.
Apparatus for simultaneously measuring and displaying as defined in ciaim 1 further comprising indicator means for identifying one or the other of said line-to-line and line-to-neutral measuring mode selected.
Dependencies are inferred from the claim text.