JPS6313524Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply circuit for an electric heater of an electrical device in which either a single-phase or three-phase power source is selectively used.

Conventionally, single-phase 200V or three-phase 200V AC power sources have been selectively used in heating electrical equipment such as air conditioners, and in this case, the electric heater's power supply circuit is connected to a terminal board as shown in Figure 1. Two 350W electric heaters 2,
3 and 200W electric heaters 4 are connected in delta via relay switches 51 and 52. Reference numeral 6 denotes a phase changeover switch provided in the wiring connecting both ends of the electric heater 4, which is closed when a single-phase 200V power source is used, and opened when a three-phase 200V power source is used. or,
Connection terminal D is connected to connection terminal B on the load side,
A primary winding 71 of the step-down transformer 7 is connected between connection terminals A and D. Further, the secondary winding 72 of the step-down transformer 7 is connected to an electric heater control circuit 9 via an operation switch 8, and the control circuit 9 controls energization of the heater relay 5 of the relay switches 51, 52. The single-phase 200V power supply 10 is connected to connection terminals A and B at the shipping destination as shown in Figure 2, and the three-phase 200V power supply 11 is connected to connection terminals A and B at the shipping destination as shown in Figure 3. and C are connected.

Therefore, when a single-phase 200V power supply 10 is used,
Phase changeover switch 6 is closed. When the operation switch 8 is closed, the heater relay 5 is energized by a command from the control circuit 9, and the relay switches 51, 5 are energized.
2 is closed. At this time, the electric equipment is electric heater 4.
is short-circuited by the phase changeover switch 6, so the electric heaters 2 and 3 perform a heating operation of 700W.
In addition, when the three-phase 200V power supply 11 is used, the phase changeover switch 6 is opened and used, and when the operation switch 8 is closed, the electric heaters 2, 3, and 4 are used.
A heating operation of 900W is performed. Single phase like this
Three-phase has smaller heating capacity when using 200V power supply
This is because the operating cost per unit W is higher than when using a 200V power supply, and to prevent the amount of current from increasing and to standardize the wiring capacity.

In the conventional power supply circuit described above, it is necessary to switch the phase changeover switch 6 according to the power supply, and if the switch 6 is forgotten to switch, there is a risk that the specified heating capacity will not be obtained or a short circuit between phases will occur. . or,
The connection of the power supply line to the terminal board 1 was also easy to make a mistake, and there was a risk of incorrect wiring.

The present invention was developed in view of the above-mentioned facts, and it is possible to use a simple circuit connection using a terminal board in the power supply circuit of an electric heater of an electric device in which a single-phase or three-phase AC power source is selectively used. The purpose of the present invention is to enable common use with any AC power source, to improve safety by omitting a phase changeover switch, and to provide a power supply circuit for an electric heater that is free from incorrect wiring of the power source. .

Hereinafter, one embodiment of the present invention will be described based on the drawings. The difference in Figure 4 from Figure 1 is terminal board 1.
The power supply sides of connection terminals C and D are short-circuited in advance. This short circuit is performed using a short circuit plate 12 as shown in FIG. is the connection terminal C,
It is installed so as to block the power supply insertion port of (d). The dial 13 is silk-printed on a black insulating material, for example, so that connection terminals A and B are connected to a single-phase power supply, and connection terminals A and B are connected to a single-phase power supply.
It clearly states that B and C are connected to a three-phase power supply, and it is required to remove the shorting plate 12 when using a three-phase power supply.

Therefore, as shown in Figure 7, the single-phase 200V power supply 1
When in use, it is impossible to attach the power line to the connection terminals C and D unless the shorting plate 12 is removed, and the power line is securely attached to the connection terminals A and B while looking at the dial plate 13. The electric heater 4 is reliably short-circuited by the wiring between the connecting terminals B and D, the short circuit plate 12, and the wiring between the connecting terminal C and the electric heaters 3 and 4, and a heating operation of 700 W is performed.

On the other hand, as shown in Figure 8, the three-phase 200V power supply 11
When in use, the shorting plate 12 must be removed before connecting the power wires to the connection terminals A, B, and C. At this time, the display on the dial 13 is easily visible to the construction worker, and there is no risk of incorrect wiring. . and electric heaters 2 and 3
Since the short circuit plate 12 and 4 are removed, the heating operation of 900W is ensured.

In the above-described embodiment, the other end of the electric heater 4, which is connected to the three-phase power supply connection terminal C, is connected to the non-power supply connection terminal D through the relay switch 51 and the connection terminal B. It may also be connected directly to connection terminal D. Further, the other end of the electric heater 3 may be connected to the connection terminal D so that the electric heater 3 is short-circuited instead of the electric heater 4, and the present invention has many modified embodiments.

As mentioned above, the present invention eliminates the problem of forgetting to turn off the switch compared to the conventional phase changeover switch that changes the capacity of the electric heater, and provides an appropriate heater regardless of whether a single-phase or three-phase AC power source is used. Capacity and current capacity can be selected, circuits can be shared, and safety is high, and the number of contact connection points is reduced, making it possible to reduce costs. Furthermore, if the dial plate is attached using a short circuit board as in the embodiment, correct wiring can be indicated and required at the same time.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing an example of a conventional circuit, Figs. 2 and 3 are explanatory diagrams showing an example of use of the conventional circuit, Fig. 4 is an electric circuit diagram showing an example of the proposed circuit, and Fig. 5 is a perspective view illustrating how the shorting plate is attached to the terminal board used in this example, Figure 6 is a front view of the dial plate used in this example, and Figures 7 and 8 show examples of how the proposed circuit is used. It is an explanatory diagram. 1...Terminal board, i~d...connection terminals, 2~4...
...Electric heater, 10...Single-phase 200V power supply, 11...
...Three-phase 200V power supply, 12...Short circuit board, 13...Dial board.

Claims (1)

[Scope of claim for utility model registration] (1) Three electric heaters are connected in delta to three of the four connection terminals provided on the terminal board,
Two of the three connection terminals are shared with the single-phase three-phase power supply, and the other one is dedicated to the three-phase power supply, and two electric heaters are connected at one end to the connection terminal dedicated to the three-phase power supply. An electric heater characterized in that the other end of one of the terminals is connected to the remaining non-power supply connection terminal to short-circuit the three-phase power supply exclusive connection terminal and the non-power supply connection terminal when using a single-phase power supply. Power supply circuit. (2) Connect a shorting plate to the connection terminal for three-phase power supply and the connection terminal for non-power supply on the terminal board, attach a dial plate that closes the power supply side insertion part of both connection terminals with the shorting plate, and connect the three-phase power supply. A power supply circuit for an electric heater according to claim 1, characterized in that the shorting plate and the dial plate are removed during use.