SU396634A1 - Phase meter - Google Patents

Description

one

iB of the proposed phase meter for measuring the angle of the phase shift between two periodic voltages, one of which is a reference calibrated in amplitude, connected to a serial depy containing a resistor, an astatic milliammeter and a thyristor, and the second to the cathode-control electrode of the thyristor, protected by a diode from the negative half cycle of this voltage. In addition, the reference voltage is calibrated with the same milliammeter using a resistor and a toggle switch switching the milliammeter terminal, which has a common point with the thyristor anode, to the second pole of the source of voltage being calibrated.

This increases the reliability of the phase meter.

The drawing shows a schematic diagram of a phase meter.

The phase meter contains a resistor 1, an astatic milliammeter 2, a toggle switch 3, a thyristor 4, a diode 5, a resistor 6, terminals 7, 8 and 9. The positions 10 and // indicate the sources of periodic voltages, the phase relationships of which are measured.

To measure the phase shift angle, one of the voltages is applied to terminals 7, 8, and the second to terminals 8, 9. The resistance of the resistor 6 before measurement must be such that the thyristor is closed.

Using a milliammeter using a resistor / when the toggle switch 3 is turned on, the position “Calibration is set to the current value corresponding to a fixed voltage applied to the thyristor. After that, the toggle switch 3 is switched to the Phase Measurement position, and the thyristor 4 is opened by decreasing the resistance value of the resistor 6.

Through a milliammeter with an open thyristor flows a periodic pulsed current. The duration of the pulses in each positive field depends on the angle: the phase shift between the voltage sources 10 vi 11. In this connection, the average current flowing through the milliammeter also depends on and is proportional to this shift. The maximum amount of current is pr and shear angle equal to

zero (the thyristor is open, and the current in the circuit flows through a full half-period), and the current is minimal (the thyristor is closed and there is no current in the circuit during the entire half-period) - at 180. For direct reading of the scale angle}

The milliammeter is graded in angular units (degrees).

, At the time of measurement, sources 10 and 11 are united by one pole at terminal 8. If such a combination is unacceptable for any reason, then one of the voltages

must be connected to a phase meter via a transformer.

To measure the phase relationship between voltage and current in one circuit, as a source voltage, it is necessary to take the voltage drop across the resistance connected in series to this circuit.

Item of Contents

Phase meter, thyristor, astatic, thyristor, milliampere meter with - scale, graded in angular units, toggle switch and resistors, characterized in that, in order to increase reliability, one of the sources of periodic voltage, which is on-line, is connected through a series-connected resistor , an astatic milliamp meter, a tumbler to the anode of the thyristor, and a second source through a resistor, a diode to the cathode junction - the control electrode of the thyristor.

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