CN101764427A - Automatic power switching device - Google Patents

Abstract

A power supply automatic switching device, which includes a three-phase power supply circuit, the inner ends of the three-phase power supply circuit are respectively connected in parallel to the three wires of the transformer power switching circuit and the generator power switching circuit, and the three-phase wires are connected There is a contactor contact at each place, a transformer power supply control delay circuit is connected to the outside of the two live wires of the transformer power switching circuit, and a generator power supply is connected to the outside of the two live wires of the generator power switching circuit Control the delay circuit, which is also to install a fuse on the two loop wires respectively, and connect a circuit composed of a contactor coil and its contacts and a circuit composed of an indicator light and its switch in parallel between the two fuses . The device has the functions of automatic power switch, network power priority, safe and reliable use, and low cost, and is especially suitable for small electrical equipment.

Description

A power automatic switching device

Technical field:

The invention is an automatic power switching device suitable for safe switching between the power grid power supply of small electric equipment and the power supply of a self-provided generating set.

Background technique:

At present, township enterprises and kilns are equipped with backup power while using grid power. The general capacity is between 150KW-400KW. Some of them often have three-phase parallelism between generator and grid power due to unreasonable equipment installation or improper operation. The phenomenon of short-circuiting caused the generators to burn out continuously; some enterprises used generator sets to supply power when there was no electricity, and they did not know how to turn off the generators when the power grid came in, resulting in waste. In addition, there are certain risks in the operation of high-power power supply or electrical equipment. Some large enterprises use ring network cabinets, but due to the high price of ring network cabinets, most small enterprises do not use this automatic switching device.

Invention content:

The task of the present invention is to provide an automatic power switching device which is convenient to switch, safe and reliable to use, and low in cost.

The technical solution of the present invention is accomplished in the following manner, which includes a three-phase power supply circuit, which is characterized in that: the inner ends of the three-phase power supply circuit are respectively connected in parallel to the three phases of the variable voltage power supply switching circuit and the generator power supply switching circuit There is a contactor contact at the connection of each three-phase wire on the lead wire, and a transformer power supply control delay circuit is connected to the outside of the two live wires of the transformer power switching circuit, which is on the two loop wires Install a fuse separately, and connect the time relay coil, the intermediate relay coil, the indicator light and its switch and the circuit composed of the power control contactor coil and its control switch in parallel between the two fuses. There is a generator power supply control delay circuit connected to the outside of the two live wires. This circuit is also installed with a fuse on the two loop wires. The parallel connection between the two fuses is composed of a contactor coil and its contacts. A circuit and a circuit consisting of an indicator light and its switch. The device has the functions of automatic power switch, network power priority, safe and reliable use, and low cost, and is especially suitable for small electrical equipment.

Description of drawings:

Accompanying drawing is the electrical schematic diagram of the present invention.

Detailed ways:

Embodiment is further described in conjunction with accompanying drawing, as shown in accompanying drawing, it is on the three-phase wire that is respectively connected in parallel with a transformer power switching circuit 1 and a generator power switching circuit 4 at the inner end of a three-phase power supply circuit 5, A contactor contact J1 and J2 are respectively provided at the junction of each three-phase wire, and a transformer power supply control delay circuit 2 is connected to the outside of the two live wires of the transformer power switching circuit. A fuse FU1 and FU2 are respectively installed on the fuse, and the time relay coil SJ/J3, the intermediate relay coil ZJ/J4, the indicator light ZD1 and its switch J1-2 are connected in parallel between the two fuses, and the contactor coil is controlled by the power supply. A circuit composed of J1 and its control switches ZJ1-2, SJ3-4, and J2-1; a generator power control delay circuit 3 is connected to the outside of the two live wires of the generator power switching circuit. A fuse FU3 and FU4 are respectively installed on each of the two loop wires, and a circuit composed of a contactor coil J2 and its contacts 2J1-1 and J1-1 and a circuit composed of an indicator light ZD2 and its switch J2 are connected in parallel between the two fuses. -2 constitutes the circuit.

The working principle of this device is that the transformer power switching circuit is connected with the transformer power control delay circuit through a fuse, the generator power switching circuit is connected with the generator power control delay circuit through a fuse, and the grid power and generator power are respectively controlled by a 100-630A contactor J1 (transformer power supply) and J2 (generator power supply), in order to control the on-off of the two power supplies. When the generator is used for power supply, if the grid suddenly receives power, the generator power control circuit is disconnected through the transformer control contactor J1 contact, and the generator power control circuit is immediately cut off. The transformer power supply will automatically open the transformer power supply control circuit with a delay of a few seconds through the intermediate relay ZJ and the time relay SJ, thereby controlling the closing of the contactor J1, so that the transformer power supply is connected. The principle of grid power priority is realized for reliable automatic switching. At the same time, in order to prevent the large current from sparking when the dual power supply is switched instantaneously, the time relay SJ is used to delay for 2 seconds to complete the automatic switching device of the grid power supply and the generator power supply for the electrical equipment. Uninterrupted power supply. This device can be installed in a small distribution box or meter box, and the control capacity can be between 10KW-300KW.

Claims (1)

1. automatic power-supply switch, it includes a three phase supply circuit, it is characterized in that: be connected in parallel on respectively in the inner of three phase supply circuit on three leads of variable-voltage power supply switching circuit and generator power supply switching circuit, be respectively equipped with a contactor contact in each three-phase conducting wire junction, on two live wires of transformer frequency response switching circuit, control timing circuit to being externally connected with a transformer frequency response, this loop is that a fuse is installed respectively on two return wires, between two fuses, be connected in parallel to time relay coil, the auxiliary relay coil, indicator light and switch thereof and the circuit that constitutes by power supply control contactor coil and control switch thereof, on two live wires of generator power supply switching circuit, control timing circuit to being externally connected with a generator power supply, this loop also is that a fuse is installed respectively on two return wires, circuit and a circuit that is made of indicator light and switch thereof of being connected in parallel between two fuses and being made of contactor coil and contact thereof.

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