JPS6155352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a timer for star-delta activation control that automatically switches between star connection and delta connection.

Conventionally, in this type of timer, when the power is turned on, a first timer that performs star connection (hereinafter referred to as Y connection) is excited, and after a certain period of time has passed from power on, a first timer is activated that performs delta connection (hereinafter referred to as Δ connection).
It is known that a second timer is excited to perform the following.

However, in this type of device, the delay time is set using a resistor and a capacitor, so if the setting time is long, the entire timer becomes large. I was not suited to do so. Furthermore, when switching from the Y connection to the Δ connection, there is a time when both the first and second timers are turned on, which increases power consumption and requires an increase in circuit capacity.

The present invention has been made in view of the above points, and is compact and allows for accurate adjustment of the switching setting time for switching from Y connection to Δ connection over a wide range. The present invention provides a timer for star-delta activation control in which both the first relay and the second relay are not driven.

Next, one embodiment of the present invention will be described based on the drawings.

1 is a power supply section as a power source. This power supply section 1
, a delay circuit (to be described later) generates a DC voltage by stepping down the commercial power supply 2 with a transformer _2a , rectifying it with a bridge 3, smoothing it with a capacitor 4 and a resistor 5, and further regulating the voltage with a Soener diode 6. 11
is being input.

11 is a delay circuit using a one-chip element. The delay circuit 11 is formed by organically connecting an oscillation circuit 12, a frequency dividing circuit 13, a counting circuit 14, an output circuit 15, an auto-reset circuit 16, and the like. First, this delay circuit 11 is connected to the terminal 17.
When voltage is input from _a , _17b , the auto-reset circuit 16 operates to activate the oscillation circuit 12 and the counting circuit 1.
As a result, the first output terminal _21a outputs an "H" signal and the second output terminal _21b outputs an "L" signal. After this, the oscillation circuit 12
starts oscillating. At this time, the oscillation frequency is adjusted by adjusting the variable resistor 19 of the frequency adjustment circuit 18 connected to the external terminal 12 _a of the delay circuit 11 . The oscillation frequency of this oscillation circuit 12 is counted by a frequency dividing circuit 13. The frequency division number of this frequency division circuit 13 is set by a switch 20 forming a frequency division number adjustment circuit connected to the external terminal _13a of the delay circuit 11. For example, when the count is 10.
It functions to output one pulse when it reaches .
The output of this frequency dividing circuit 13 is counted by a counting circuit 14, and when the count reaches 1024, for example, the output circuit 15 is driven to invert the output signals of the first and second output terminals 21 _a and 21 _b . do.

The first output terminal _21a of the delay circuit 11 is an NPN transistor (hereinafter referred to as Tr) 23 as a first switching element whose emitter is grounded.
is connected to the base of the circuit via a resistor 22. A coil portion of a first relay 24 is connected between the collector of this Tr 23 and the positive electrode side of the bridge 3. The contact portion of this first relay 24 has a Y connection portion 24 _a and _a Δ connection portion 24 _b as shown in FIG.
The connection portion 24 _b is turned off, and in the non-excited state, the Y connection portion 24 _a is turned off and the Δ connection portion 24 _b is turned on.

The second output terminal 21 _b of the delay circuit 11 is the resistor 3
1 and a capacitor 32.
The output of this integrating circuit 33 is used as a second switching element whose emitter is grounded.
It is input to the base of Tr 35 via a Zener diode 34. A second relay 36 is connected between the collector of this Tr35 and the positive side of the bridge 3.
The coil section is connected. The contact portion of this second relay 36 is connected to the Δ connection portion 24 of the first relay 24.
It has a Δ connection part 36 _a connected in series with _b , and this Δ connection part 36 _a is turned on in an excited state.

Next, the operation of this embodiment will be explained.

First, when the power supply section 1 is turned on, the delay circuit 11
is reset by the auto-reset circuit 16,
An "H" signal is output to the first output terminal 21 _a , and an "L" signal is output to the second output terminal 21 _b . Therefore, Tr23 is turned on and Tr35 is turned off, and as a result, only the first relay 24 is energized and Y-connection is performed. This Y-connection state continues for a predetermined set time T until the output of the delay circuit 11 is inverted.

Here, if the oscillation period of the oscillation circuit 12 set by the frequency adjustment circuit 18 is t ₁ and the frequency division number of the frequency dividing circuit 13 set by the switch 20 is n, then the count up of the counting circuit 14 is
1024, the above set time T is expressed by the formula: T=t ₁ ×n×1024.

Next, after turning on the power supply unit 1, the above set time T
Consider the behavior when .

After this set time T has elapsed, the output signals of the first and second output terminals 21 _a and 21 _b of the delay circuit 11 are inverted. At this time, Tr2 during switching time t ₀
3 and 35 are both turned off, and both the Y connection and the Δ connection are turned off. this is,
This is because the second output terminal 21 _b of the delay circuit 11 is input to the base of the Tr 35 via the integrating circuit 33 . That is, Tr23 is turned off at the same time as the output of the delay circuit 11 is inverted, but Tr35 is turned off for a time _t0 until the output of the integrating circuit 33 exceeds the threshold voltage of Tr35.
This is the reason for the switching time t ₀ .

After this switching time t ₀ has elapsed, Tr35
is turned on, the second relay 36 is excited, and the Δ connection portion 36a is turned on. Here, since the first relay 24 is in a non-excited state, the Δ connection portion 24 _b of the first relay 24 is turned on, and becomes a Δ connection state.

Note that in order to change the wiring to Y-connection again, it is sufficient to turn off the power supply section 1.

In this embodiment, transistors are used as the first and second switching elements, but the present invention is not limited to this, and other elements such as FETs may also be used.

According to the present invention, since a one-chip element is used in the delay circuit, it is possible to reduce the size and improve economical efficiency, and the setting time until the star connection is switched to the delta connection after the power is turned on can be reduced as described above. By adjusting the oscillation frequency inside the delay circuit and adjusting the frequency division number of the frequency divider circuit, it is possible to set the frequency over a very wide range with high precision.Furthermore, an integrating circuit is provided at the output of the delay circuit, so that when the output of the delay circuit is reversed, By turning off the Y connection and turning on the Δ connection with a time difference, it is possible to prevent both the first and second relays that perform the above connection from being driven at the same time, and reduce the power supply capacity and circuitry required for driving. Capacity can be reduced.

[Brief explanation of the drawing]

The figures show an embodiment of the star-delta start control timer of the present invention, and Fig. 1 is its electric circuit diagram, and Fig. 2 is a circuit showing the connection of the contact portions of the first and second relays. FIG. 3 is a time chart showing the on/off state of the power supply and the accompanying driving states of the first and second relays. DESCRIPTION OF SYMBOLS 1... Power supply part as a power supply, 11... Delay circuit, 12... Oscillation circuit, 13... Frequency division circuit, 18
... Frequency adjustment circuit, 20 ... Frequency division number adjustment circuit,
21 _a ...First output terminal, 21 _b ... Second output terminal, 23... Transistor as a first switching element, 24... First relay, 33...
Integrating circuit, 35...transistor as a second switching element, 36...second relay, T...
...Predetermined set time.

Claims (1)

[Claims] 1. A timer having a first relay that is driven to perform star connection when the first switching element is turned on, and a second relay that is driven to perform delta connection when the second switching element is turned on. When connected to this power supply and turned on, the "H" signal is output to the first output terminal and the "L" signal is output to the second output terminal.
a delay circuit configured with a one-chip element that outputs a signal and inverts the signals at the first and second output terminals after a predetermined set time has elapsed;
The delay circuit includes a frequency adjustment circuit and a frequency division number adjustment circuit externally connected to the oscillation circuit and the frequency division circuit inside the delay circuit, and an integration circuit connected to a second output terminal of the delay circuit. The first output terminal of the integrating circuit is connected to the first switching element, and the output of the integrating circuit is connected to the second switching element.
Timer for delta start control.