JP3261015B2 - Power supply circuit for water tank appliances - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit for an electric appliance for an aquarium, and more particularly to a power supply circuit for an electric appliance for an aquarium that detects a leakage and stops the power supply.

[0002]

2. Description of the Related Art In addition to water tanks, water tank appliances such as pumps, heaters, fluorescent lamps, and the like are often used for breeding appreciation fish, which has become a boom in recent years. Among them, pumps, heaters, and the like used in water are waterproofed with resin or the like. In addition, when a fluorescent lamp is set on the water tank, there is a danger of electric leakage if the fluorescent lamp falls into the water tank due to feeding, cleaning, hitting, or earthquake of the appreciation fish. In particular, when an electric leakage occurs in a water tank for breeding saltwater fish or the like, when a person touches the seawater, the earth becomes ground, and a large current of about 50 mA flows to the person, which is extremely dangerous.

In order to use such aquarium appliances safely, it is necessary to connect these aquarium appliances to a commercial power supply via an earth leakage breaker and to obtain ground from the aquarium. However, it is extremely rare in today's Japanese houses that the ground can be installed in places where water tanks are installed, such as entrances and living rooms. Even if you use only the earth leakage breaker without connecting the ground,
Unless human beings are grounded and electricity flows through the water, the power of appliances cannot be shut off, and eventually power can not be shut off unless electricity flows to humans, which is very dangerous. was there.

[0004] On the other hand, home electric appliances around water such as a washing machine are provided with various types of leakage prevention measures, but none of appreciation fish appliances have been provided with such leakage prevention measures.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional apparatus, and when the electric appliance for a water tank leaks in the water tank, the power supply for the water tank is automatically cut off. It is intended to provide a power supply circuit of a product.

[0006]

Means for Solving the Problems In order to achieve the above object, in a power supply circuit of an aquarium appliance according to the present invention, a heater to be supplied to an aquarium is connected to a power supply circuit of the aquarium appliance and provided. A relay having a contact in the power supply circuit;
A switching element with a control electrode for controlling the excitation of the relay; and an input terminal connected to a control electrode of the switching element and an electric leakage detection circuit connected to the water tank, and electric leakage from the heater in the water tank. At the input end through the water.

[0007] With the above configuration, when a leakage of the heater occurs in the water tank, the leakage is detected via the water in the water tank at the input end put into the water tank, and the switching element is turned on to turn on the switching element. The trip coil can be excited to stop supplying power to the aquarium appliance. The aquarium appliance can be used safely even in places where grounding cannot be obtained.

[0008]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing one embodiment of a power supply circuit of an electric appliance for aquarium according to the present invention.
Is a water tank, 2 is a heater, 3 is a power supply circuit, 4 is a relay, 5 is a switching element with a control electrode, and 6 is a leakage detection circuit.

The water tank 1 is filled with fresh water, seawater, or the like. The water tank 1 is provided with a heater 2 for keeping fresh water or seawater at a predetermined temperature. The heater 2 is composed of, for example, a ceramic heater in which a heating element made of tungsten (W) or molybdenum / manganese (MoMn) is embedded in a plate-like or rod-like ceramic body, and is supplied with electric power from a commercial power supply 7 through a power supply circuit 3. Is done.

The power supply circuit 3 includes a contact 4a of the relay 4
Are interposed. A rectifier circuit 8 is provided in the feeder circuit 3 behind the contact 4a of the relay 4 in a branched manner. This rectifier circuit 8 includes four diodes D ₁ , D
₂ , D ₃ and D ₄ are connected in a bridge form. That is, the power supply circuit 3 is connected between the diodes D ₁ and D _{4 and} between the diodes D ₂ and D ₃ . The trip coil 4 of the relay 4 is provided between the rectifier circuit 8 and the power supply circuit 3.
b is provided.

The diodes D ₁ and D ₃ and the diode D
_2, between D _4, a control electrode with the switching element 5 consisting of a thyristor or the like is connected. The switching element 5 with a control pole is not limited to a thyristor, and may be a transistor or the like. Between the anode A and the cathode K of the control electrode with the switching element 5, resistor R ₁ and capacitor C ₁
Are connected in series. With this a resistor R ₁ and capacitor C ₁ in series between the anode A and the cathode K of the switching element 5, to suppress a voltage increase rate due to surge (dv / dt), the switching element 5 consisting of a thyristor Malfunction can be prevented.

An earth leakage detection circuit 6 is connected to the control pole G of the switching element 5. The input terminal 6a of the electric leakage detection circuit 6 is provided immersed in the water of the water tank 1, and the other end is connected to the control pole G of the switching element 5. The electric current I ₀ flowing through the electric leakage detection circuit 6 is provided to the electric leakage detection circuit 6.
By limiting a resistance R ₂ for determining the sensitivity it is provided.

A resistor R ₃ and a capacitor C are connected between the leakage detecting circuit 6 and the cathode K of the switching element 5.
₂ are connected in parallel. The capacitor C ₂ is provided in order to prevent a malfunction of the switching element 5 by delaying by a time constant with respect to the resistance R ₂ provided in the leakage detecting circuit 6. Resistor R ₃ serves as a discharge resistor for the capacitor C _2.

In the circuit configuration as described above, when the insulation of the heater 2 is maintained, the leakage current I ₀ does not flow, so that the switching element 5 is off and the contact 4a of the power supply circuit 3 is closed. Up to. On the other hand, when the heater 2 deteriorates and dielectric breakdown occurs, the leakage current I ₀ flows. When the leakage current reaches the gate trigger voltage of the switching element 5, the switching element 5 is turned on, and the exciting current I _{1 is} supplied to the trip coil 4b. Flows, and the contact 4 of the power supply circuit 3 opens. As a result, the power supply to the heater 2 in the water tank 1 is immediately stopped.

When a bridge diode composed of diodes D _{1 to} D ₄ is used as the rectifier circuit 8 as in the above-described example, the current of the power supply circuit 3 is full-wave rectified. This is suitable because insulation deterioration can be detected. If such an effect is not expected, a half-wave rectifier circuit can be used.

[0016]

Further, the power supply circuit of the present invention is housed and provided in one housing 9, and a plug (not shown) is provided at one end of the power supply circuit 3.
When the power cord 10 having the above-described configuration is provided and an outlet 11 is provided at the other end of the power supply circuit 3, the plug of the conventional water tank heater can be inserted into this outlet and used as it is.

As described above, in the power supply circuit of the electric appliance for aquarium according to the present invention, the heater supplied to the aquarium is connected to the electric supply circuit of the electric appliance for the aquarium, and the contact is interposed in the electric supply circuit. A relay and a switching element with a control electrode for controlling the excitation of the relay are provided, and an input terminal is connected to a control electrode of the switching element and an input terminal is connected to the leakage detection circuit provided in the water tank, and the leakage from the heater is provided. Since the input end is detected through the water in the water tank at the input end, when a leak occurs in the heater of the water tank, the switching element is turned on by detecting at the input end put into the water tank through the water. By doing so, it is possible to excite the trip coil of the relay and stop supplying power to the heater. The heater can be used safely even in a place where the ground cannot be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a power supply circuit of an aquarium appliance according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water tank, 2 ... Heater, 3 ... Power supply circuit, 4
... Relay, 5 ... Switching element with control pole,
6 ... Leakage detection circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A01K 63/00-63/06 H02H 3/08-3/253 H05B 3/00-3/86

Claims (2)

(57) [Claims] 1. An electric power supply circuit for an aquarium electric appliance is supplied to the aquarium.
Provided by connecting the heater to be a relay which is interposed contacts power feeding circuit is provided and a control Kiwametsuki switching element for controlling the excitation of該継collector, to the input end to the control electrode of the switching element is the water tub The supplied leakage detection circuit is connected and provided , and the leakage from the heater is conducted through the water in the water tank.
And a power supply circuit of the appliance for the aquarium , which is detected at the input terminal . 2. A power supply circuit for an aquarium appliance according to claim 1, wherein a bridge diode connected to the power supply circuit is provided between the relay and the switching element with a control electrode.