JPS5819607Y2 - AC input switch - Google Patents

Description

[Detailed description of the invention] The present invention relates to an AC input switching device that supplies power to the electrical device at a predetermined voltage regardless of the voltage of the AC power source when connecting an AC power source to an electrical device. The present invention relates to a protection circuit that prevents overcurrent from being applied to electrical equipment due to failure or the like.

Generally, in factories, etc., 110
V and 220V are connected, but if you connect the power source of an electrical device such as a measuring instrument incorrectly, the device may burn out or malfunction.

Therefore, some devices are equipped with an AC input switch that automatically switches the input circuit of the electrical device according to the voltage of the connected AC power source.

FIG. 1 shows a conventional AC input switch.

The switching relay X1 has an excitation coil configuration that is activated or deactivated depending on the voltage when the AC power supply AC is connected, and switches the primary side tab of the power hole quadrance T that receives the AC power supply AC as an input.

The secondary side of the transformer T is connected to an electrical device to supply alternating current.

For example, the tap P1 of the transformer T is for 220V, and the tap P2 is 1
Pulled out for 10V.

With this configuration, the connected AC power supply AC is 22
If it is 0■, the switching relay X1 is activated, switching its movable contact from the illustrated state to the tag Pl side, and lowering the output voltage of the transformer T to 110V.

When the AC power source AC is 110V, the switching relay X1 is kept inactive, its contacts are kept in the illustrated state, and the output voltage of the transformer T is set to 110V.

By providing such an input switching device built into the electrical device or provided separately from the electrical device, accidents such as burnout of the electrical device due to overvoltage input due to incorrect connection of the AC power source can be prevented.

However, if the switching relay Xl has a failure such as a disconnection, the contacts will not be switched, and this poses the problem of causing an accident such as burnout of the device, similar to a connection error in a device that does not have a switching device.

The object of the present invention is to provide an AC input switching device that solves the above problems and also provides the effects described later.

FIG. 2 shows an embodiment of the present invention.

The difference between this figure and FIG. 1 is that the excitation coil is connected in series to the excitation coil of switching relay X1, and
The present invention is characterized in that it is provided with a protective relay X2 which is activated when energized and connects between the alternating current power supply AC and the transformer T.

By providing this protection relay X2, switching relay X1
However, if there is a failure such as a disconnection, relay X2 will not operate, and AC power supply A will
No connection is made between C and transformer T.

Therefore, it is possible to prevent an accident in which an overvoltage is applied to an electrical device even though it is connected to a high-voltage alternating current power source AC.

In addition, when the connected AC power supply AC is assumed to be 110V or 220V, the relay
It is sufficient to use a configuration that operates as described above and operates regardless of the AC voltage of 110V or 220V as long as there is no failure in the switching relay X1.

For example, the relay X1 is configured to operate at 170 mm or more and fall off at 120 mm.

In the past, the protective relay X2 had a contact structure that closed the contact after the switching operation of the switching relay X1 when the AC power supply was connected.

With this structure, when connecting an AC power source, the transformer T
It is possible to prevent the AC power supply from being connected and temporarily applying high voltage input before the tap reaches the desired switching state.

In addition, in the embodiment, the switching relay X1 is not limited to switching between two types of alternating current voltages, and the contacts can also be applied to those provided in the quadratic A law of a transformer.

According to the present invention, a protection relay is provided that is connected in series with a switching relay that switches the tap of the power hole quadrance according to the voltage of the AC power supply, and the operation of this relay, that is, the switching relay is normal. Since the AC power source and the transformer are connected by the operation under the condition that this is the case, it is possible to prevent overvoltage from being input to the electrical equipment due to failure of the switching relay.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional AC input switching device, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. Xl...Switching relay, Xl...Protection relay, T.
・・Power hole cadence, D・・Electrical device.

Claims (1)

[Scope of utility model registration request] A switching relay that sets the output of the input quadrance to a predetermined voltage by switching the tap of the power hole quadrance according to the voltage of the AC power source when an AC power source as a power source is connected, and the switching relay that connects the excitation coil to a predetermined voltage. A protection relay is connected in series with the excitation coil of the invention, is activated by the energization of the switching relay when the AC power source is connected, and connects between the AC power source and the input cadence after the switching operation of the switching relay. AC input switch.