SU1472842A1 - Low-frequency phase-meter - Google Patents

Abstract

The invention makes it possible to reduce energy consumption and simplify the design of the phase meter. Parametric stabilizer is made on resistor 1 and zener diode 2 to the level of 7V. The keys 8 and 9 are controlled by the signal taken from the current sensor on diodes 12 and 13. The positive half-wave signal current sensors turn on the keys 8 and 9 and connect microammeter 3 to the voltage sensor. If the phase deviates from 90 °, the device becomes unbalanced. In the case of small deviations from 90 ° COS ϕ, the circuit and the current of the device are linearly connected, which is convenient for a direct reading of COS ϕ on the order of 0.1 ... 0.2. The use of the device eliminates the dependence of the phase meter reading on the duration of the fronts of the current and voltage signals. 1 il.

Description

The invention relates to an electrical measurement technique, is intended for measuring phase, active power factor and can be used in particular to determine active losses in coils with steel, in stators of electrical machines, etc.

The purpose of the invention is to reduce energy consumption and simplify the device, which is achieved by eliminating the input pulse shapers and power supply and depending on the phase meter readings on the duration of the current and voltage signals.

The drawing shows a circuit diagram of a low-frequency phase meter.

The device contains a limiting resistor 1 of a two-pole parametric stabilizer, a two-pole zener diode 2, which is part of the same stabilizer, a microammeter 3, a current limiting resistor 4, dividing diodes 5-7, keys 8 and 9, made in the form of np-p and p - n - p transistors, the base resistors 10 and 11, two parallel and counter-coupled diode 12 and. 13. At the same time, the first input-output of the phase meter through the limiting resistor 1 and the two-pole Zener diode 2 is connected to the common input of the phase meter, forming a parametric two-pole voltage regulator, the output of which is connected through a series-limiting resistor 4, microammeter 3, the output of which is connected with the collector of the pnp transistor 8, the emitter of which is connected to the common input of the phase meter and through dividing diodes 6. and 7 - to the collector of the pnpn of the transistor 9, the emitter of which is connected to the common output th phase meter, the base p-n-p transistor 9 through the resistor 10 is connected to the common input of the phase meter, the base of n-p-n transistor 8 through the resistor 11 - overall yield phasemeter. Two parallel and counter-connected separating diodes 12 and 13 are interconnected and connected by one common terminal to the common input of the phase meter, and the second to the common output of the phase meter, forming a current sensor.

The device works as follows

AC voltage of 100-300 V is limited parametrically

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five

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five

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five

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five

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five

by a stabilizer, made on resistor 1 and zener diode 2 (KS-175), to the level of 7 V. Electronic (transistor) switches 8 and 9 and a measuring device with a current-limiting resistor are connected via dividing diodes 5 and 6 to this 2-pole voltage 4. Switches 8 and 9 are controlled (switched on) by a signal taken from the current sensor on diodes 12 and 13 through resistors 10 and 11. Diode 7 compensates for the voltage drop on diodes 12 and 13 (0.6 V). The positive half-waves of the current sensor signal include the keys 8 and 9 and connect the microammeter 3 to the voltage sensor о If the positive half-waves of the current and voltage coincide, the readings of the device are maximum.

Claims (2)

If the phase shift between current and voltage is 90, then the device is alternately connected to the positive and negative half-waves of the voltage, the device reads in this case equal to 0. The device unbalance occurs when the phase deviates from the value 90. With small deviations, the cos Q circuit and the current of the measuring device are linearly coupled, which is convenient for a direct reference cos if of the order of 0.1 - 0, 2. The formula of the invention A low-frequency phase meter containing two keys with two resistors connected to the bases, a current-limiting resistor connected in series with a microammeter, which, in order to reduce energy consumption and simplify the device, introduced a two-pole parametric voltage regulator and separators odes, with the output of a two-pole parametric voltage regulator through a current-limiting resistor and a microammeter connected to the separation diodes, and the keys are made on sources with opposite conductivities, the transistor collectors are connected to the outputs of the separation diodes, the emitter of the pnp transistor is directly, and the base of the pnpp transistor is connected to the common input of the phase meter through parallel and counter-connected via the first base resistor dividing diodes with a common phase meter output.