CN2373932Y

CN2373932Y - Sequential control power-off protector for electric motor

Info

Publication number: CN2373932Y
Application number: CN 98233146
Authority: CN
Inventors: 高文革
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-11-06
Filing date: 1998-11-06
Publication date: 2000-04-12
Anticipated expiration: 2008-11-06

Abstract

The utility model relates to a sequential control power-off protector for a motor, which comprises a stop button, a start button, an AC contactor and a thermal relay which are connected in series between the phase B and the phase C of a three-phase power supply. The utility model has the primary structure that an intermediate relay KA and a time relay KT are connected in series between the stop button and the start button, wherein, two coils of the KA and the KT are connected in parallel; one end of each of the two coils is connected to the normally open auxiliary contact of the AC contactor, and the other end is connected with the normally closed auxiliary contact of the thermal relay. The normally open contact of the KA and the time-delay normally closed contact of the KT are connected in parallel. The utility model has the advantages of simple structure and strong protection function on the motor.

Description

Sequence motor control power-off protection apparatus

The utility model relates to a kind of at sequence motor control power-off protection apparatus.

In industrial production, the sequential control of motor is used very extensive.Advantages such as the still relay control mode that present people generally use though it has the reliability height, moves directly, and is easy to maintenance.But the applicant finds in for many years the maintenance practice in this respect: there are the following problems for normally used sequencing circuit: the function imperfection, accidents such as device damage easily take place, and therefore annual and caused a large amount of economic losses.(said typically refer to that relevant handbook, teaching material provide here; and just at widely used circuit; it comprises B that series connection inserts three-phase alternating-current supply mutually and C between mutually, the protective circuit of being made up of following electric device: stop button, start button, A.C. contactor, thermal relay.) when my personal experience repeatedly after the maintenance of accident, thinking deeply the defective that how to overcome this respect.

The purpose of this utility model is, proposes a kind of sequence motor control power-off protection apparatus, in order to reduce the damage of motor.

The purpose of this utility model is to realize like this; it comprises stop button SB3; start button SB1 and SB2; A.C. contactor KM1 and KM2; thermal relay FR1 and FR2; their series connections are in the B of three phase mains phase; between the C phase; its architectural feature is; described sequence motor control power-off protection apparatus also includes auxiliary relay KA and time relay KT; wherein KA and KT two coils from parallel connection of coils; one of coil is terminated at the auxiliary contact that A.C. contactor KM2 often leaves; its other end is connected to the normally closed auxiliary contact of thermal relay FR2 one end; the normal opened contact of KA is in parallel with the time-delay normally closed contact of KT, and their series connection insert between stop button SB3 and the start button SB1

Good effect of the present utility model is that this sequence motor control power-off protection apparatus has multiple functions such as short-circuit protection, overload protection, under-voltage protection, o-volt protection and open circuit protection.In original sequencing circuit, when above-mentioned fault appearred in control loop, it can't cut off the control power supply, caused motor M 1 to switch on for a long time, was easy to damage motor, and influence is produced.And this device is few with respect to the electric device of the required increase of former protection system, but can improve the defencive function to motor greatly.

The utility model is described in further detail below in conjunction with accompanying drawing,

Fig. 1 is the electrical connection schematic diagram of the utility model embodiment 1,

Fig. 2 is the electrical connection schematic diagram of the utility model embodiment 2.

Implement side 1 (see figure 1)

Its sequence motor control circuit operation principle is as follows:

The QS that closes a switch earlier,

Press SB1 → KM1 coil and obtain the closed self-locking of electricity → KM1 auxiliary contact → KM1 main contact closure → M1 starting,

Pressing SB2 → KM2 coil obtains the closed self-locking of electricity → KM2 normally open contact → KM2 main contact closure → motor M 2 starting → KM2 normally open contact closure → KA coils and obtains electricity → KA normally open contact closure → kM2 normally open contact closure → KT coil and obtain the normally closed time-delay contact disconnection of electricity → KT

Press stop button SB3 → KM1 coil losing electricity → motor M 1 stall → KM2 coil losing electricity → motor M 2 stalls.

In service in motor M 1, M2, if control loop breaks down, when making KM2 coil losing electricity or KM2 coil burnout, then KA, KT coil losing electricity, the KA normally open contact disconnects, and the timing closing of the normally closed time-delay contact of KT is controlled power supply like this and cut off by the KA normally open contact, motor M 1, M2 cut off the power supply at once, stop operating.

This control circuit has short-circuit protection, overload protection, under-voltage protection, o-volt protection and open circuit protection; And original sequencing circuit has only the function of short-circuit protection, overload protection, under-voltage protection and o-volt protection.

In original sequencing circuit, when above-mentioned fault appearred in control loop, it can't cut off the control power supply, caused motor M 1 to switch on for a long time, was easy to damage motor, and influence is produced.

Embodiment 2 (see figure 2)s

Second kind of sequence motor control circuit operation principle is as follows:

The QS that closes a switch earlier,

Press SB1 → KM1 coil and obtain the closed self-locking of electricity → KM1 normally open contact → KM1 main contact closure → motor M 1 starting

Press SB2 → KM2 coil and obtain electricity → KM2 normally open contact closure and obtain electricity → KT normally open contact closure → KT time-delay normally closed interlock from trivial → KM2 main contact closure → motor M 2 starting → KM2 normally open contact closure → KT coils and disconnect,

Press stop button SB3 → KM1 coil losing electricity → motor M 1 stall, press stop button SB3 → KM2 coil losing electricity → motor M 1 stall.

In service in motor M 1, M2, if control loop breaks down, when making coil KM2 dead electricity or KM2 coil burnout, KT coil losing electricity then, the KT normally open contact disconnects, the timing closing of the normally closed time-delay contact of KT, the control power supply is cut off by the KT normally open contact like this, and motor M 1, M2 cut off the power supply at once, stop operating.

Claims

1, a kind of sequence motor control power-off protection apparatus, it comprises stop button SB3, start button SB1 and SB2, A.C. contactor KM1 and KM2, thermal relay FR1 and FR2, their series connections the B of three phase mains phase, C mutually between, it is characterized in that,

Described sequence motor control power-off protection apparatus also includes auxiliary relay KA and time relay KT; wherein KA and KT two coils from parallel connection of coils; one of coil is terminated at the auxiliary contact that A.C. contactor KM2 often leaves; its other end is connected to the normally closed auxiliary contact of thermal relay FR2 one end; the normal opened contact of KA is in parallel with the time-delay normally closed contact of KT, and their series connection insert between stop button SB3 and the start button SB1.