JPS6126455A - Motor - Google Patents

Abstract

PURPOSE:To eliminate the maintenance of a brush by mounting rotor coils of an induction motor and a synchronous motor on the same rotational shaft to integrally rotate, thereby eliminating a slip ring and brushes. CONSTITUTION:Since the secondary winding 1b of an induction motor 1 and the secondary winding 2b of a synchronus generator 2 form rotor coils and the rotational shaft of the motor 1 and the generator 2 is common with the same rotational shaft 3, the both secondary windings 1b, 2b are rotated at the same rotatting speed. The windings 1b, 2b are coupled by a connecting wire 4. The field current of the generator 2 is regulated by a field control circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a motor that performs stepless speed control of a wound induction motor.

[Prior art]

Conventionally, to control the torque of a wound induction motor, a secondary resistance control method in which a resistor is inserted in series with the rotor, or a secondary excitation control method such as the Servius method or the Kramer method has been adopted.

However, in this conventional method, the power from the wires and secondary windings is taken out using slip rings and brushes, and the power is generated as resistance loss and then returned to the power supply for control, so maintenance of the brushes is required. It had some drawbacks.

[Object and structure of the invention]

Therefore, an object of the present invention is to provide an electric motor that does not require brush maintenance.

In order to achieve these objectives, this invention enables the rotating shafts of the induction motor and the synchronous generator to rotate together, and connects the rotor coil of the induction motor and the rotor coil of the synchronous generator to achieve synchronization. This is designed to control the field current of the generator. Hereinafter, the present invention will be described in detail using drawings showing embodiments.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the apparatus according to the present invention. In the figure, 1 is an induction motor, and 1ml1lb is a primary winding of the induction motor 1 (stator winding).

Secondary winding (rotor winding), 2 is synchronous generator, 2m + 2b
is the primary winding (stator winding) of the synchronous generator 2.

The secondary winding (rotary pre-winding i), 3 is a rotating shaft. Secondary winding 1b of induction motor 10 and secondary winding 2b of synchronous generator 2
constitutes a circular coil, and the induction generator 1 and synchronous generator 20 share the same rotation axis 3, so
Both secondary windings are arranged to rotate at the same number of rotations. The secondary windings 1b and 2b are connected by a connecting wire 4.

Figure 2 shows the connections of the equipment shown in Figure 1.
The same symbols are used for parts that are the same as those in the figure. In the figure, 5 is a field control circuit, 6 and 7 are breakers, and secondary windings 1b and 2b are connected in series by a connecting wire 4.

The field control circuit 5 controls the field current supplied to the primary winding 2M.

FIG. 3 shows an equal number of circuits for one phase of the induction motor 1. In the figure, G is excitation impedance, rl.

X...1 is the resistance and reactance of the primary winding 1a, i is 1
The current flowing in the secondary winding 1a, i is the induced voltage generated in the primary winding 1a, rz + xxB the resistance and reactance of the secondary winding 1b, S is the current flowing in the secondary winding 1b, Iga is the current flowing in the secondary winding 1b, ic is This is the voltage generated in the secondary winding of the synchronous generator 20.

The operation of the device configured as described above is as follows. A current is supplied from the power supply side through the induction motor breaker 7, and rotation starts. Since the primary winding 2a of the synchronous generator 2 is supplied with three-phase field current from the power source via the breaker 6, the primary winding 2a generates a rotating magnetic field that rotates at a synchronous speed. And the synchronous generator 20 secondary winding 2b
is attached to the same rotating shaft 3 as the secondary winding 1b of the induction motor 10, so voltages of the same frequency are generated in both secondary windings. At this time, the current flowing through the secondary winding 1b of the induction motor 1 can be expressed as follows.

wR*(It) jIm[Iz) ””・(2) As a result, the current! The vector diagram of 2 can be expressed as shown in FIG. 8 voltages induced in the secondary winding of the induction motor 1,
When the voltage ie induced in the secondary winding of the synchronous generator 2 is set in opposite phase and the field control circuit 5 is adjusted to change the magnitude of the voltage ic, the current ix +1( 1) and as a result, the torque can be controlled. Therefore, if the field current is controlled steplessly in the field control circuit 5, the torque of the induction motor 1 can be controlled steplessly.

The above idea is to control the torque of the induction motor 1 when it rotates, but by applying this idea at the time of starting, the current at the time of starting can be reduced for the first reason. When a motor starts, a large induced voltage is generated on the secondary side, and a very large current flows. At this time, the synchronous generator 20
A voltage ic having an opposite phase to the voltage SIC generated in the secondary winding 1b of the induction motor 1 is generated in the secondary winding. Therefore, if the field control circuit 5 is controlled to control the field current of the synchronous generator 2 and the value of the voltage Ec is adjusted, this voltage Ke acts in the direction of canceling the voltage BE2, so the induction motor
The starting current can be reduced. By performing such starting, a large-capacity motor such as a thruster motor can be started with a low current.

〔Effect of the invention〕

As explained above, in this invention, the rotor coils of an induction motor and a synchronous generator are attached to the same rotating shaft and rotated together, so both rotor coils can be directly connected. Since slip rings and brushes are not required, maintenance-free operation can be achieved, and the current flowing through the secondary winding can be controlled steplessly by controlling the field of the synchronous generator steplessly. This has the effect that the torque of the induction motor can be controlled steplessly.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the main parts of the device according to the present invention, and FIG.
The figure is a circuit diagram, FIG. 3 is an equivalent circuit diagram, and FIG. 4 is a vector diagram. 1...Induction motor, 2...e synchronous generator, l @
, 2@@@@@Primary winding, lb, 2beeL*Secondary winding, 3...Fist/rotating shaft, 4...Connection wire, 5...φ--Field control circuit@Old patent applicant Mitsui Shipbuilding Co., Ltd. agent Masaki Yamakawa (PL or 2 people) Figure 1 Figure 2

Claims (1)

[Claims] It consists of a wound induction motor, a synchronous generator whose rotating shaft is formed to rotate together with the rotating shaft of the wound induction motor, and a field control circuit that adjusts the field current of the synchronous generator. The rotor coil of the generator is an electric motor connected to the rotor coil of a wound induction generator.