CN2265027Y - Starting arrangement of asynchronous motor - Google Patents

Abstract

The utility model discloses a starting device for a three-phase squirrel cage induction motor which requires star-shaped wire connection during starting and requires triangle wire connection during running. In the utility model, each phase inlet terminal of each winding of the motor is respectively connected with a three-phase power supply, the phase outlet terminal of each winding of the motor is respectively connected with two normally closed contacts which are controlled by one same contactor, the phase inlet and phase outlet of each winding are connected with the three normally open contacts which are controlled by the same contactor, and the contactor which is used for controlling the normally open contacts and the normally closed contacts is controlled by a time relay.

Description

The asynchronous motor starting device

The utility model relates to a kind of the need when being used to start need be converted to the starting device of the three-phase squirrel cage induction motor of triangle wiring with star-star connection when running well.

Need make star during starting---the asynchronous motor of triangle conversion is used the starting equipment of more complicated in actual use always.For example Chinese utility model patent 88208866.8 disclosed high power motor automatic control equipments, though have effect preferably, its structure is very complicated.

The purpose of this utility model provides a kind of prior art deficiency that overcomes, the more simple asynchronous motor starting device of structure.

The purpose of this utility model adopts following measure to realize: the line end that advances to join of each winding of motor is connected with three phase mains respectively, each winding of motor line end that goes out to join is connected by the normally-closed contacts of same contactor control in twos with two, alternate the using respectively of advancing mutually and go out of each winding connected by three normally opened contacts of aforesaid same contactor control, the contactor that is used to control described normal open and close contact is controlled with a time relay, and time relay institute preset time can be determined when starting to rated speed according to motor the required time.By described technical characterictic of the present utility model as seen, the wiring of power supply and motor is not star-star connection when described contactor is not worked, and power supply and motor are the triangle wiring when described contactor is worked.The utility model in use, behind motor connecting power, because the effect contactor of the time relay is not worked, normally opened contact in the utility model is opened a way at this moment, and the normally-closed contact closure, motor starts under the lower voltage under the star-star connection state, when motor speed is accelerated gradually, when reaching rated speed, the time relay has also reached the predefined time, promptly become another kind of operating state, and make and worked by the contactor of its control, at this moment be subjected to the normally opened contact of contactor control to become closure state, be subjected to the normally-closed contact of contactor control then to become open-circuit condition, thereby make the wiring triangular in shape of motor and power supply, motor is run well.

The used contactor of the utility model can promptly adopt its electric current allowable and be changed a social system by the identical A.C. contactor of controlled motor operating current with the existing A.C. contactor transformation of the way.The electric current that existing A.C. contactor normally-closed contact allows to pass through only is 1/2nd of its nominal current, for adapting to requirement of the present utility model, only needs that normally-closed contact is changed to sectional area and can allow greatly to get final product by the contact of its nominal current.Realize that best approach of the present utility model is to adopt the special A.C. contactor that meets aforementioned requirement.

The utility model has the advantages that: structure is very simple, whole device only uses a time relay and an A.C. contactor to get final product, its wiring is also very simple, available simple control circuit is realized the safe starting of motor, even can directly use the three-phase plug-in strip to cooperate the safe starting of realizing motor with the utility model; Secondly, overall dimension of the present utility model is very little, is example with the used starter of 75KW motor, and its overall dimension only is 200 * 180 * 160mm, can easily place in the motor and need not extra setting device; The 3rd is that work effect of the present utility model is very reliable, and the conversion of the star when can be completely achieved motor starting---delta connection reduces starting current, realizes the safe handling of motor.

Description of drawings

Fig. 1 is an embodiment of the present utility model

Motor power (output) is 22KW in the embodiment that Fig. 1 provides.Each winding of motor line end A that advances to join, B, C joins with each of three phase mains respectively, and the going out to join between line end X and Y and join in twos with normally-closed contact (1) and (2) between Y and Z of motor, advancing mutually and going out of each winding is alternate, promptly between A and X, use normally opened contact (3), (4), (5) to link to each other respectively between B and Y and between C and Z.Any two alternate, for example alternate with B mutually at A shown in the figure at power supply with lead relay turn-on time (6), and controlled A.C. contactor (7) with the time relay and worked.The time relay that present embodiment adopts is SJ 121 type electronic relays because the operating voltage of this relay only be 220V, so set up in the present embodiment one its elementaryly be the transformer of 380V (8).It is the B-27 type contactor that Shanghai produces that this reality is put A.C. contactor used in the example, and its normally-closed contact is replaced by the bigger contact of sectional area through repacking.Use in this example with three-phase plug-in strip (9) and control as power supply.Present embodiment is when work, the time relay (6) is under a kind of operating state after by plug-in strip (9) energized, the A.C. contactor (7) that is subjected to its control is not worked, at this moment normally opened contact (3), (4), (5) open circuit, and normally-closed contact (1), (2) closure, motor and power supply are star-star connection, and begin to start, when the rotating speed of motor during near rated speed, the time relay (6) is when reaching preset time, the time relay (6) overturns, and is in another kind of operating state, and the contactor (7) that is subjected to its control is started working, at this moment normally-closed contact (1), (2) become open-circuit condition, and normally opened contact (3), (4), (5) closure, delta connection is changed in the wiring of motor, and enters in the normal rotation process.

Claims (2)

1, a kind of asynchronous motor, starting device, it is characterized in that motor each winding advance mutually end respectively with power connection, each winding of motor line end that goes out to join is connected by the normally-closed contacts of same contactor control in twos with two, alternate the using respectively of advancing mutually and go out of each winding connected by three normally opened contacts of aforesaid same contactor control, and described contactor is by a time relay control.

2, starting device according to claim 1 is characterized in that the described time relay, contactor and motor control with same switch.