SU51118A1 - Method for improving commutation of a single-phase collector AC motor - Google Patents

Description

proposes a method for improving the switching of a single-phase AC collector motor, which is started up by direct current with the help of an auxiliary motor-generator and switched, when it reaches normal speed, to an AC network.

The drawing shows a schematic diagram of the electrical connections of the collector engine with an auxiliary generator.

The auxiliary generator 7 initially operates as a shunt generator and feeds the collector engine 5 during its acceleration.

For the subsequent conversion of the entire installation to the AC mode after engine acceleration, a knife switch / motor 5 to the main transformer / is used, the switch // translates to the position shown in dotted lines and closes the knife switches /// and IV. In this case, a pulsating voltage will be applied to the excitation winding 6 of the auxiliary generator and it will start to work as an AC collector. At the same time, the disconnecting switch V inductive resistance 13 is turned off, the generator / is turned on in the auxiliary pole circuit of the engine 5.

Thus, the advantage of DC motor acceleration is achieved: the absence of a transformer electromotive force, the absence of a pulsating moment, the provision of a large starting torque with a small starting current, and the subsequent use of an auxiliary unit to improve commutation. To achieve this goal, it is necessary to create an induction that changes according to the law Bd - K j K F -

ft

that is, one component must be proportional to the load, and the other is proportional to the flow of the main poles of the engine and inversely proportional to the number of its revolutions. To create the first component in the circuit of additional poles 6, the excitation winding 5 main poles is included, and to create the second component of a constant electromotive force freH

generator 7 is subtracted by the electromotive force of the Iadvi engine ... Lastly, as is well known, varies in proportion to the revolutions (taking /; const) and therefore the difference

W Eg Yagen. - mot. will decrease with increasing engine speed. Thus, the resulting voltage for supplying the winding of the additional points is obtained from the following components: the electromotive force of the generator 7, the counter-electromotive force of the engine and the voltage of the excitation winding of the main points, and is correctly compensated for in the switched motor.

The drawing contains the following designations: 4-compensation motor winding 5, 5 excitation winding of the auxiliary generator 7, 9-auxiliary voltage transformer, 10-resistance for limiting the current in the circuit of additional poles, 11-resistance for limiting the current in the secondary winding of the transformer 2, / 2-regulating resistance.

The subject matter of the invention.

A method for improving the commutation of a single-phase collector AC motor starting from a direct current using a DC generator driven by a synchronous motor and then switched to an AC network, characterized in that said DC generator switches into a circuit after the engine accelerates additional poles of the latter, and for using it as an alternating current generator, a supervoltage transformer is excited in order to obtain, in combination with iem at the terminals of the armature component of the engine induction of additional poles is inversely proportional to the number of revolutions of the engine and nroportsionalnoy its main stream.