JPH09312224A - 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, current transformer for monitoring the current of the transformer TR1, a 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 by using a contactless 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 load equipment by switching a tap of a transformer using a non-contact switch and adjusting an output voltage of the transformer is shown in FIG. 3, for example. It was The power saving device 11 connects the transformer TR2 to the single-phase three-wire type electric circuit and is provided with four taps. Contactless switches SW11, SW12, SW13, SW14 are connected to the respective taps as switches for selecting the tap closest to the preset value while monitoring the voltage of the primary side or the secondary side of the transformer TR2. , 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 problems of the conventional power saving device described above, an object of the present invention is to keep the transformer open even at a light load when a current equal to or lower than the minimum load current at which the contactless switch does not turn on completely flows. The present invention provides a power saving device that does not damage the non-contact switch, monitors the voltage on the primary or secondary side of the transformer, and switches the tap of the transformer using the non-contact switch. In a power-saving device that regulates the output voltage of the device to suppress the power consumption of the load device, 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 the current to flow to the electric path. When the current does not reach the set value, normal operation is performed without adjusting the output voltage of the transformer, and when it exceeds the set value, the output voltage of the transformer is adjusted to reduce the power consumption of the load equipment. It is to perform a power-saving operation to win.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The voltage on the primary side or secondary side of a transformer is constantly monitored and a tap closest to a set value is automatically selected by a contactless switch. The current on the primary side of the transformer is detected by the current detector, and the current control circuit connected to this current detector allows normal operation without adjusting the output voltage of the transformer when the current flowing in the circuit does not reach the set value. If it exceeds the set value, the output voltage of the transformer is adjusted to perform the power saving operation to suppress the power consumption of the load equipment.

[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, 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, The load device L is connected to the secondary side of the transformer TR1. The current control circuit 2 includes a current transformer C
A current flowing through the primary side of the transformer TR1 is detected by T, and is composed of a current-voltage conversion circuit 3, a rectifying / smoothing circuit 4, an integrating circuit 5, a level detector 6, and a relay RY.

The voltage on the primary side or secondary side of the transformer TR1 is constantly monitored, and the contactless switches SW1, SW2, SW
3, SW4 automatically selects the tap closest to the set value. The current on the primary side of the transformer TR1 is detected by the current transformer CT which is a current detector, and the current control circuit 2 connected to the current transformer CT turns on the relay RY when the current flowing in the electric path does not reach the set value. Then, the normal operation is performed without adjusting the output voltage of the transformer TR1, and when the set value is exceeded, the output voltage of the transformer TR1 is adjusted to perform the power saving operation of suppressing the power consumption of the load device L.

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 determined that the load is light, the relay RY of the current control circuit 2 is turned off, and the output voltage of the transformer TR1 is not adjusted and normal operation is performed.

In normal operation, the magnet contactor MC
3 is turned on, the magnet contactor MC1 is turned off, the magnet contactor MC2 is turned on, and the magnet contactor MC3 is turned off, so that it is judged as a light load until the current flowing in the X phase becomes 1 A or more, and the output voltage of the transformer TR1. Does not adjust and performs normal operation.

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
Output voltage is adjusted to perform power saving operation for suppressing the power consumption of the load device L.

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.

[0013]

As described above, the power saving device according to the present invention is
In a power-saving device that monitors the voltage of the primary side or secondary side of the transformer, switches the tap of the transformer using a non-contact switch, and adjusts the output voltage of the transformer to suppress the power consumption of the load device. The current on the primary side is detected by the current detector, and the current control circuit connected to the current detector performs normal operation without adjusting the output voltage of the transformer when the current flowing in the electric circuit does not reach the set value. ,
When the value exceeds the set value, the output voltage of the transformer is adjusted to perform the power saving operation that suppresses the power consumption of the load device, so that the transformer does not turn on completely. There is an effect that there is no risk of breaking the non-contact switch without opening.

[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 non-contact switch, and adjusts the output voltage of the transformer to suppress the power consumption of load equipment. In, the primary side current of the transformer is detected by the current detector, and the current control circuit connected to the current detector does not adjust the output voltage of the transformer when the current flowing in the electric circuit does not reach the set value. The power-saving device is characterized by performing normal operation during the normal operation and adjusting the output voltage of the transformer when exceeding a set value to suppress the power consumption of the load device.