CN86206606U

CN86206606U - Motor protector capable of protecting motor against reversal, phase failure and overload

Info

Publication number: CN86206606U
Application number: CN 86206606
Authority: CN
Inventors: 姬金富
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-12-11
Filing date: 1986-12-11
Publication date: 1988-04-20

Abstract

The utility model discloses a motor protector capable of protecting motor against reversal, phase failure and overload. Under the condition of without any triode, diode and resistor, the utility model adopts a novel circuit to solve the problems of the burning out of a motor caused by phase failure and overload while operating and the reversal of the motor caused by the changes of the phase order of a three-phase power supply. The utility model can solve the reversed orders of the wiring modification of an electric network and a motor caused by the phase failure and the overload of the motor, can adjust the phase orders in time, and can guarantee the motor to operate in a normal direction. The utility model has the advantages of advanced structure, low cost, convenient operation, simple production and fewer elements.

Description

Motor protector capable of protecting motor against reversal, phase failure and overload

This utility model is invented, and is used for direction operation, the phase shortage overload protection of motor.

At present motor stator is to open phase protector, use that element is many, volume greatly, complex manufacturing, cost be higher, especially the directed open phase protector of electronic type is subjected to Temperature Influence serious, therefore, its reliability is also poor.

At the defective of above motor stator to open-phase protection; through ruminating over and testing; the novel circuitry phase that selects is adopted in this utility model invention; it is simple in structure, element is less; be not subjected to Temperature Influence; good reliability, low cost of manufacture, it can solve the directed phase shortage of motor and the problem under the overload situations this utility model invention.

The utility model main feature is: do not adopt electronic component; choosing phase and open-phase protection circuit are by two resistance hole coils; be connected on respectively A mutually with C power supply mutually on; an electric capacity is connected on the B phase power supply; form a star circuit jointly by them; and cause serious neutral potential drift by this circuit, see central point drift degree result of calculation:

N=-214.8V

The voltage that A phase, C phase power supply and neutral potential stack afford the A phase relay:

A=20V

, the voltage that the C phase relay affords: C=386

, this shows that phase selector relay work principle is: the stack of phase voltage and central point drifting voltage greater than phase voltage for C mutually, less than phase voltage be the A phase, and have the relay tip that is chosen as the C phase to devote oneself to work.

Electromotive power source is once connection, select circuitry phase to analyze after, the relay that is chosen as the C phase enters operating state, and the positive sequence power supply is sent into motor, guarantees that motor is all the time towards a direction running; If because the change of electrical network phase sequence and motor change the phase sequence confusion that the end of a thread causes, protector is aligned phase sequence automatically.

In service, power fuse fusing or loose contact, motor when phase-deficient operation the phase sequence circuit also along with phase shortage, in this case, every of phase selector relay only bears≤voltage of 190V, and therefore, phase selector relay withdraws from two-phase work immediately from three phase mains, wherein one do not constitute the loop mutually, guaranteed that motor motor under the phase shortage situation is not burnt out.

In service, electromotor overload, electric current increases, the thermal relay action, working mutually selecting circuitry phase to withdraw from one immediately in the control point of thermal relay, causes automatically and select the circuitry phase phase shortage, makes phase selector relay withdraw from the power supply that motor is introduced in two-phase, wherein another does not constitute the loop mutually, allows motor stop operating.

Phase selector relay is specific (special) requirements, and two groups of AC coil are arranged in the relay, two pairs of normal opened contacts of every group of AC coil control, the normal working voltage 〉=320V of every group of coil, return voltage 〉=220V.Its volume is little, can be directly installed on the terminal box of motor (former connector cover is taken away) and have again that cost is low, power consumption is little and wiring, characteristics such as easy to use.

In order to further describe operation principle of the present invention, see figure (1)

Dotted line partly is the control part (disconnecting link or A.C. contactor contact) of motor among the figure (1), and dotted line the right to motor is a key wiring diagram of the present invention.

1ZJ and 2ZJ are connected on respectively in A, the C two-phase, and the B electric capacity that joins constitutes the circuit of an asymmetric star structure.C phase power supply and neutral potential are superimposed, greater than phase voltage, and 2ZJ starting, two pairs of normal opened contact closures of 2ZJ, connect motor circuit, another directly introduces motor mutually, if phase sequence changes over backward, 1ZJ is as the C phase, and 1ZJ starts, and two docking points of 1ZJ are aligned phase sequence automatically.

Under the phase shortage situation, 1ZJ or 2ZJ only bear the voltage about 190V respectively, therefore 1ZJ, 2ZJ two docking points discharge, one phase power supply motor does not constitute the loop, motor stops, motor transships under working order, thermal relay flows through the overload current of A, B phase respectively, make the RJ action, the RJ contact disconnects the 1ZJ loop, and electric capacity and 2ZJ divide voltage equally, the voltage that the 2ZJ relay coil affords is less than 190V, the 2ZJ contact disconnects motor two-phase power supply (1ZJ is same), and one does not constitute the loop mutually, and motor quits work.

The mounting means of motor is seen figure (2)

The connector cover of motor is taken down, and " motor orientation, phase shortage, overload protective device " is directly installed on the terminal box of motor.

Claims

1, a kind of " the directed phase shortage overload protective device of motor " is characterized in that:

A, two inductance coils and an electric capacity are connected on respectively forms asymmetric star circuit on A, B, the C three phase mains, realize the phasing open-phase protection,

B, control the wherein phase of asymmetric star circuit, realize overload protection by the contact of thermal relay.

2, by claim 1. described " the directed phase shortage overload protective device of motor ", it is characterized in that: assert that electric capacity is connected on the B phase, two groups of coils are connected on A, C phase respectively.

3, by claim 1. described " the directed phase shortage overload protective device of motor "; it is characterized in that: the thermal relay contact is controlled any phase of asymmetric star circuit; under overload situations, cause asymmetric star circuit phase shortage; utilize the phase shortage of asymmetric star circuit, 1ZJ or 2ZJ are deactivated down in working order.

4, it is characterized in that by claim 1. described " the directed phase shortage overload protective device of motor ": 1ZJ, 2ZJ and Я J relay are in an integral body, adopt the special reversible bidirectional relay of two-phase, can be directly installed on the motor.