Wiring error protection device and method for single-phase AC three-speed motor

Abstract

The invention provides a wiring error prevention device and method for a single-phase AC three-speed motor. The device comprises a motor terminal block, a temperature controller terminal block, a first relay, a second relay and a third relay, wherein the motor terminal block is connected with the single-phase AC three-speed motor; the temperature controller terminal block is connected with an external single-phase AC power supply through a temperature controller; the first relay, the second relay and the third relay constitute a protective logic loop and are connected between the motor terminal block and the temperature controller terminal block; where a wiring error occurs, the protective logic loop can disconnect all the first relay, the second relay and the third relay, thereby avoiding motor erroneous operation which causes rise of voltage and damages the single-phase AC three-speed motor.The device can be used for protecting the motor and preventing the motor from being burnt out in the case of a wiring error. The device not only can be applied to the fan-coil unit of a central air conditioner but also can be widely used for wiring error prevention for the single-phase AC three-speed motor.

Description

technical field [0001] The invention relates to motor protection technology, in particular to a wiring error protection device and method for a single-phase AC three-speed motor, belonging to the field of electrical technology. technical background [0002] At present, many devices use single-phase AC three-speed motors (220V±10% / 50Hz). For example, most of the fan coil units of central air conditioners use single-phase AC three-speed motors. see figure 1 , the coil of the single-phase AC three-speed motor M is composed of a main coil L0 and three secondary coils L1, L2, and L3, and a three-speed tap is arranged between the three secondary coils L1, L2, and L3 to connect with the motor terminal block PM, and they are respectively Yes, connect to the high-speed terminal of the motor terminal block PM through the red line R, connect to the medium-speed terminal of the motor terminal block PM through the blue line BU, and connect to the low-speed terminal of the motor terminal...

AI Technical Summary

Problems solved by technology

The single-phase AC three-speed motor M has a rapid speed in a short period of time, and the coil temperature rises sharply. After a few minutes, it exceeds the temperature resistance level of the coil enameled wire, destroys the insulation of the enameled wire, and causes a short circuit of the coil, until the motor is burned, and even a fire is caused.

Therefore, the external zero line must be connected to the zero line terminal (yellow line Y) of the single-phase AC three-speed motor M. Therefore, once a wiring error occurs, the protection of the single-phase AC three-speed motor M becomes a major issue.

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