SU432645A1 - DEVICE FOR START-UP ASYNCHRONOUS PHASE MOTOR - Google Patents

Description

A device for starting a three-phase asi-synchronous electric motor is known, comprising resistances included in the motor-rotor circuit and contactors for connecting them. The contacts are connected in groups in parallel to the steps of the resistances of each phase of the ipoTopa region, forming parallel or parallel-series current-symmetrical connections. However, this device is difficult and inefficiently uses the volume of resistance.

The proposed device differs from the actual one in that the rotor orphans in it are connected in a triangle, and the contacts of the contactors of each stage together with the corresponding resistances form the closed closed triangles.

Such an embodiment of the device makes it possible to simplify the circuit and increase the efficiency of using the volume of resistances. In addition, in order to increase versatility, additional resistances are included in each closed T1-triangle in series with each contact.

To reduce the switching currents of the first adjustment steps parallel to the original triangle, an additional triangle of resistances or a star is switched off.

FIG. 1 shows the initial circuit of the rotor resistances of the proposed device; in fig. , 2-4 - the resulting connection schemes of the rotor resistance stages at the start; in fig. 5 is a diagram of rotor resistances with additional resistances.

In the INITIAL state (Fig. 1), before the induction of the asynchronous electric motor, the rotor resistances are connected in a "triangle" connected by the L, V, C strings to the rotor phases of the electric motor. The rotor resistances of the subsequent phase B, C, A and the odd and rotary resistance stages of the previous phase C, A, B. When the contacts 2U - 4) close (Figs. 2, 3 and 4), parallel triangle connections are formed. in by successively dividing one of the original ial "triangles into two equal" triangle. The magnitude of the resistances of the individual stages of the rotor resistances R is determined by the relationship:

Rl / 2 "-1 C,

where „is the resistance of the design stage

rotary resistance; - resistance to the previous stage of the rotor resistance;

C is the correction value of the resistance, which determines the required change in the starting moment in the individual steps of the regulation.

In order to reduce the switching current in the first steps of the adjustment, in a “similar state of the circuit,” two triangles are included in parallel, the conductivity of each of which in the half T1 is required.

With this division of the "triangle" current surge will be reduced.

In order to increase the versatility of the device (Fig. 5), in separate steps, in addition to each contact, an additional resistance is included in each closed triangle. In this case, the "triangle of resistance is transformed into three asymmetres. And-zny" stars.

Subject invention

Claims (3)

1. A device for the induction of an asynchronous phase electric motor containing resistance stages for motor stages connected to ipoTo.pa and contactors for switching them, characterized in that, in order to simplify the circuit and reduce the volume of resistances, the rotor resistances are connected in delta and the contacts The contactors of each step in-place with internal resistances corresponding to these steps form internal closed triangles. 2. The device according to claim 1, characterized in that, with a slot for increasing versatility, additional resistances are included in each closed triangle in series with each contact. 3. Device. By 1P. 1, characterized in that, in order to reduce the switching currents. In the first control steps, pa-. parallel to the original “triangle, an additional“ triangle of resistances or a star is included. The priority of clause 2 is to be calculated as of 07.27.71. f ttmnopy 3JieKinpo utafisJ