SU32056A1 - Method for determining dissipation factor in electric machines - Google Patents

Description

The magnetic flux spreads over the entire length of the magnetic circuit, but this distance reaches the greatest value in the air gap. This value is taken into account when calculating the machine.

known coefficient of scattering

f S -Ts--, where Ft is the flow of poles, Fy -

but

FLOW COR. The scattering coefficient is determined with a fixed machine connected according to the diagram shown. An additional winding is connected to the poles of the machine at the poles of the AC source according to the already known method of determining the scattering coefficient. A voltmeter FI is measured parallel to this winding, measuring the voltage applied to the winding and regulated by a rheostat. The brushes of the machine are shifted from the neutral zone of idling by 90 electrical degrees so that the sides of the short-circuited sections. were under the middle of the poles, to the brushes attached322

voltmeter 1/2 through the main excitation winding passes a direct current regulated by a resistor Rz-

When an alternating current is passed through the additional winding, a pulsating magnetic flux induces a variable a in the winding. D. s., recorded by a voltmeter Ug. The readings of voltmeters K and V-i will characterize the values of pulsating magnetic fluxes Fsch and Fd passing through poles and measles. Then, as is well known, the coefficient of dispersion will be equal to the ratio of the voltages shown by the voltmeters V and Kg, reduced to the same number of turns.

-ij1 / 2 1Г „

where N is the number of core conductors and W is the number of turns of the coil.

If the number of turns of the additional winding.

will be

W-JL,

that

It should be noted that in order to obtain sufficiently accurate results, it is desirable that the number of turns and the voltage Vi be taken small in order for the pulsating flux to be small compared with the main magnetic fluxes.

The coefficient of dispersion, as is known, depends on the saturation of the machine. By changing the excitation current of the main coils, we can remove the curve 5 / (Itn), which gives the dependence of the scattering coefficient on saturation. If the design of the machine does not allow the brushes to move, then the connection of the voltmeter V can be accomplished using contacts, finding the desired position of the collector diametrically opposite plates for bipolar machines) by the maximum deviation of the voltmeter V2 at constant readings of the voltmeter Ki. As can be seen from the foregoing, the proposed method requires only one additional winding of the pole of the machine as opposed to the well-known methods that require putting a spool into measles, which is associated with damage to the core. In compounding machines as

additional scraper can be used seriaznaya winding, and in this case for the production of experience does not require any devices.

The subject matter of the invention.

Claims (2)

1. A method for determining the dissipation factor in electric machines of direct current using an auxiliary coil fed to the poles, fed by alternating current, so that the magnitude of the dissipation factor is determined by the ratio of the electromotive forces applied to the terminals of the auxiliary winding and another induced by first on the crust, characterized in that in order to obtain an electromotive force compared with the electromotive force of the auxiliary winding at the poles, the brushes are shifted from the neutral by an angle of 90 electric eskih degrees so that these brushes measure the desired voltage caused by varying the flow of auxiliary windings on the poles. 2. In the method according to claim 1, in the case of determining the coefficient of dispersion in co-round machines, use as an auxiliary winding at the main poles of the excitation series winding.