JPS6310536Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase sequence detection circuit. Conventionally, there is a rotary phase detector as a phase order detector, but it is impossible to incorporate this into a hardware circuit as a circuit to check the phase order, and further miniaturization is required. Can not.

The object of the present invention is to provide a phase sequence detection circuit that is small and inexpensive and can be easily used for on-site adjustment of three-phase electrical equipment, and can also be incorporated into other circuits as a phase sequence confirmation circuit.

FIG. 1 is a circuit diagram of a phase sequence detector according to the present invention. In the figure, F ₁ to _{F 3} are RS flip-flops,
F ₄ is a JK flip-flop, OR is an OR element,
AND is an AND element (however, the buffer described later is
When configured with a PNP transistor, it is a NAND element. ), B is a buffer that amplifies the input signal using a transistor etc. and outputs it, L is a light emitting diode, D ₁ to _{D 6} are diodes, I ₁ to _{I 3} are inverters,
_C1 to _C4 are capacitors, and _R1 to _R13 are resistors. In such a circuit configuration, a three-phase power supply RST is connected to the input sides of the resistors _R1 to _R3 , respectively. and,
When the R phase, S phase, and T phase are input in the correct phase order as shown in the diagram, 60Hz power flows to the light emitting diode L and it lights up, and conversely, the phase order of the R phase, S phase, and T phase is reversed. When input in phase, no current flows through the light emitting diode L, so it does not light up. Based on this result, it is possible to determine whether RST is in positive phase order or reverse phase order. The operation shown in FIG. 1 will be explained below with reference to FIG. First, when a three-phase power supply is connected to the circuit shown in Figure 1, it is rectified by diodes _D4 to _D6 , and the DC voltage
Vcc is obtained (C ₄ is for taking ripple)
It is applied to the anode side of the light emitting diode L.
On the other hand, the voltage of each phase is half-wave rectified by diodes D ₁ to _{D 3} and RS flip-flops F ₁ to F 3 .
It is input to the reset input terminal R via the set input terminal S of _F3 and the inverters _I1 to _I3 . (Here, C ₁ to C ₃ and R ₁₀ to R ₁₂ are inserted to remove noise.) Therefore, when connected to a three-phase power supply in positive phase order as shown in the figure, , the outputs from the output terminals Q of flip-flops _F1 to _F3 have the waveforms shown in FIG. 2A to C, respectively. or,
The JK flip-flop _F4 is reset when the output of the flip-flop _F1 is input to the reset input terminal in negative logic, that is, during the period when the low potential "L" is applied, so the period shown in FIG. It will be reset. With such conditions,
The outputs of flip-flops F _{2 and} F 3 are connected to the clock input terminal C of JK flip-flop F ₄ as an OR element.
Input via . Therefore, at the time when the output of _F2 rises, _F4 is inverted and outputs "H", but on the other hand, at the time when the output of _F3 rises, a low potential "L" is applied to the R terminal of the JK flip-flop _F4 . Therefore, even if the output of _F3 is input to the C terminal, flip-flop _F4 is not inverted, so the output of flip-flop _F4 remains "L". Therefore, the output of F ₄ has the waveform shown in FIG. 2 (E).

As a result, in the case of a positive phase input, the output of the AND element AND is made to flow to the light emitting diode L via the current buffer B as shown in FIG.
On the other hand, if the input is in a reverse phase state, there is no point at which the output "H" of _F4 and the output "H" of _F3 overlap, so there is no current in the light emitting diode L as shown in Figure 2. It will not flow. Therefore, in the case of a positive phase input, the light emitting diode L lights up with a current of 60 Hz, but in the case of a negative phase input, it does not light up at all, making it possible to detect the phase order.

The above example shows the case where detection is performed by lighting up a light emitting diode, but if this circuit is incorporated into another circuit, the presence or absence of the 60Hz waveform can be used as a phase sequential detection waveform in the other circuit. good. Therefore, the present invention is small, inexpensive, and
A phase sequence detection circuit that can be incorporated into other circuits is obtained.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of an embodiment of a phase sequence detection circuit according to the present invention, and FIG. 2 is a waveform diagram for explaining the operation of FIG. 1.

Claims (1)

[Scope of utility model registration request] Rectifying elements D ₁ , D ₂ , D ₃ to which the three-phase AC voltage is input for each phase; the output of the rectifying element of the corresponding phase is input to the set input terminal S, and the output of the same rectifying element is input to the inverter I. The R.
S flip-flops F ₁ , F ₂ , F ₃ ; OR elements OR that input the set outputs of flip-flops F ₂ and F ₃ for the second and third phases among the three R.S flip-flops; A JK flip-flop _F4 inputs the output of the element OR to the clock input terminal C, and also inputs the output of the R-phase RS flip-flop _F1 to the reset input terminal R in negative logic; the output of the JK flip-flop _F4 and the S A phase sequence detection circuit consisting of an AND element or a NAND element that inputs the output of the phase RS flip-flop _F2 .