JPH09312223A - Power saving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power saving apparatus having a transformer which is never be open and hence does not break a contactless switch even at a low load state with a current below the min. load current which will not perfectly turn on this switch. SOLUTION: The power saving apparatus 1 comprises a transformer TR1 connected to a single-phase three-wire power line, contactless switches SW1-SW4 for changing four prim. taps of the transformer TR1, contact switches of relays RY1-RY4 parallel connected to the switches SW1-SW4, current transformer for monitoring the current of the transformer TR1, current control circuit 2 connected to the current transformer, magnet contactors MC1-MC3, and circuit breaker NFB. A load apparatus L is connected to the sec. of the transformer TR1. The current control circuit 2 detects the current flowing in the prim. of the transformer TR1, using the current transformer, and is composed of a current-voltage converter, a rectifier-smoother, an integrator, a level detector and a relay.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a power saving device that suppresses power consumption of load equipment by switching a tap of a transformer using a switch and adjusting an output voltage of the transformer.

[0002]

2. Description of the Related Art Conventionally, a power saving device for suppressing power consumption of a load device by switching a tap of a transformer by using a switch and adjusting an output voltage of the transformer is shown in FIG.
It was as shown in The power saving device 11 connects the transformer TR2 to the single-phase three-wire type electric circuit and is provided with four taps. Each tap has a contactless switch S as a switch for selecting the tap closest to a preset value while monitoring the voltage of the primary side or the secondary side of the transformer TR2.
W11, SW12, SW13, and SW14 are connected, and the taps are switched by making them conductive.

[0003]

However, the contactless switch does not turn on completely unless a current exceeding the minimum load current flows, and all the contactless switches turn on during a light load in which a current below the minimum load current flows. Therefore, the primary side of the transformer TR2 is opened, and accordingly the non-contact switches SW11, SW12, SW13, S.
There is a drawback in that a high voltage is generated at both ends of W14 and these contactless switches may be destroyed.

[0004]

SUMMARY OF THE INVENTION In view of the above problems of the conventional power saving device, an object of the present invention is to keep an open state of a transformer even under a light load in which a current below a minimum load current at which a contactless switch does not turn on completely flows. The present invention provides a power-saving device that does not damage the switch, monitors the voltage on the primary or secondary side of the transformer, and switches the tap of the transformer using the switch to change the output voltage of the transformer. In the power saving device that adjusts to reduce the power consumption of load equipment,
The current on the primary side of the transformer is detected by a current detector, and a current control circuit connected to the current detector causes a contact switch to switch the tap of the transformer when the current flowing in the circuit does not reach a set value. When the set value is exceeded, the tap of the transformer is switched by the non-contact switch.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The current on the primary side of a transformer is detected by a current transformer, which is a current detector. The contact switch switches the taps, and when the set value is exceeded, the contactless switch switches the taps.

[0006]

1 and 2 show an embodiment of a power saving device according to the present invention. Hereinafter, the present invention will be described with reference to the drawings.

The power saving device 1 includes a transformer TR1 connected to a single-phase three-wire type electric circuit and contactless switches SW1, SW2, SW for switching four taps on the primary side of the transformer TR1.
3, SW4 and relays RY1, RY2, RY3, RY4 which are contact switches in parallel with the respective non-contact switches
, A current transformer CT for monitoring the current of the transformer TR1, a current control circuit 2 connected to this current transformer, magnet contactors MC1, MC2, MC3, and a circuit breaker NFB.
And a load device L on the secondary side of the transformer TR1.
Is connected. The current control circuit 2 detects the current flowing through the primary side of the transformer TR1 by the current transformer CT, and includes a current / voltage conversion circuit 3, a rectifying / smoothing circuit 4, an integrating circuit 5, a level detector 6, and a relay RY. .

The current on the primary side of the transformer TR1 is detected by a current transformer CT which is a current detector. The current control circuit 2 connected to the current transformer CT indicates that the current flowing in the electric path does not reach a set value. Relays RY1 and R that are contact switches
The taps are switched by Y2, RY3, RY4, and when the set value is exceeded, the contactless switches SW1, SW2, SW
Taps are switched by SW3 and SW4.

Now, assuming that the transformer tap current flowing in the X phase is 0.5 A and the current set value is 1 A, the set value is 1 A.
Since the transformer tap current is smaller than that, it is judged as a light load, the relay 7 of the current control circuit 2 is turned off, and the transformer T
R1 is a relay RY1, RY2, R which is a contact switch
The taps are switched by Y3 and RY4.

When the current flowing in the X phase exceeds 1 A,
The relay RY of the current control circuit 2 is turned on, and the transformer TR1
The taps are switched by the contact switches SW1, SW2, SW3 and SW4.

It should be noted that the current control circuit 2 is not limited to this embodiment, and can be changed as appropriate without departing from the gist of the present invention.

Further, although the relay is used as the contact switch in the present embodiment, the contact switch is not limited to this, and it is possible to appropriately change the magnet contactor and the like without departing from the gist of the present invention.

[0013]

As described above, the power saving device according to the present invention is
In a power saving device that monitors the voltage on the primary side or secondary side of a transformer, switches the tap of the transformer using a switch, and adjusts the output voltage of the transformer to suppress the power consumption of load equipment, the primary side of the transformer. Current is detected by the current detector, and when the current flowing in the electric circuit does not reach the set value by the current control circuit connected to the current detector, the tap of the transformer is switched by the contact switch to set the set value. When it exceeds, by switching the tap of the transformer with a contactless switch, the transformer does not turn on even when the load is light and a current below the minimum load current flows, and the contactless switch is destroyed. There is no fear, and since the reed switch is turned on and off only when the load is light, the contact capacity can be reduced and the manufacturing cost can be reduced. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a power saving device according to the present invention.

FIG. 2 is a block diagram of a current control circuit of a power saving device according to the present invention.

FIG. 3 is an explanatory diagram of a conventional power saving device.

[Explanation of symbols]

1 ... Power saving device, 2 ... Current control circuit, 3 ... Current-voltage conversion circuit, 4 ... Rectifying / smoothing circuit, 5 ... Integrating circuit, 6 ... Level detector, RY ...・ Relay, TR
1 ... Transformer, SW1, SW2, SW3, SW4
..Solid state switches

Claims (1)

[Claims] 1. A power-saving device that monitors the voltage on the primary side or secondary side of a transformer, switches the tap of the transformer using a switch, and adjusts the output voltage of the transformer to suppress power consumption of load equipment. The current on the primary side of the transformer is detected by a current detector, and a current control circuit connected to the current detector causes a contact switch to switch the tap of the transformer when the current flowing in the circuit does not reach a set value. The power saving device is characterized in that the tap of the transformer is switched by a non-contact switch when the set value is exceeded.