SU974311A1 - Device for measuring magnetic induction - Google Patents

Description

(5) DEVICE FOR MEASURING A MAGNETIC The invention relates to a measurement technique and 8 devices for measuring magnetic fields by an induction method can be used. A device for measuring magnetic fields by an induction method is known in which a conductor system in the form of a coil of a special geometric shape rotates in a magnetic field around an axis perpendicular to the winding axis. 1, To collect the voltage in such devices, collectors are used to which the coil terminals are connected. However, short-term ruptures of contacts are observed in the collectors, creating noise, reducing the measurement accuracy. It is also known a device, the content of an induction coil, kinematically coupled to a rotary drive, and a recording device 2. Induction A disadvantage of the known device is low accuracy, since the source of short-time interruptions of the contacts is not eliminated. The purpose of the invention is to improve accuracy. The goal is achieved in that a device for measuring magnetic induction, containing induction coils, kinematically connected to a drive: rotation, and a registering device, is inserted into a sine-cosine rotating transformer, the rotor windings of which are connected to two mutually perpendicular induction coils, and the stator winding the windings are connected to a registering device, while the rotor of the sine-cosine rotary transformer is connected to the induction coils and the rotational drive, and fixedly mounted in relation to the rotor. The drawing shows a diagram of the device. The device consists of two identical induction coils 1 (schematically depicted one turn of the coils), the winding axes of which lie in the same plane and mutually perpendicular. Their windings are connected to the windings of the rotor 2 of a sine-cosine rotating transformer (CCWT), 10 kinematically connected with induction coils 1 and drive 3 of rotation. The static winding k of the SSCT is connected to a recording device 5, for example, a digital voltmeter. It is fixed motionless with respect to the rotor 2. The device works as follows. The rotation drive 3 is energized and the recording device 5- The induction coils 1 begin to rotate. Under the action of the magnetic induction component of the field, parallel to the plane of rotation of the winding axes of the induction coils 1, a variable emf is induced at their terminals

e in iv t,

(1) 62 E, uj t,

E,

E- - amplitude values; signals;

LA, is the rotation frequency of the coils;

t - time

These signals enter the phase windings of the rotor 2 of the SSCT and, there, 3 their mutually perpendicular windings are signals of the form (1) without taking into account the transmission coefficient.

These voltages are applied to one of the single-phase stator windings of the ACS. There will be a voltage at its terminals.

(Wt-cos 0) 44- (5U) t-5iniut),

(2)

where k is the transmission coefficient of the STS; W is the frequency of rotation of the rotor 2. The rotor 2 of the STS and the induction coils 1 are fixed on the same shaft, therefore their rotation speeds are the same, i.e.

U) W, {3)

and substituting (W) in (2), we obtain

W

e 2ujt, 5

Claims (2)

1.Ornatsky P.P. Automatic measurements and devices. Kiev, Higher School% 1980, p. 192, fig. it.lla. 2. USSR Author's Certificate No. 301651, cl. G 01 R 33/02, 1971 (prototype). where EP, is the amplitude value of the voltage on the leads of the stator windings, proportional to the induction of the measured floor B. Expression C) shows that the voltage on the leads of the stator is proportional to the RMS of the coils, or the measured induction. In this case, the frequency of the voltage is doubled in relation to the frequency of rotation. Thus, the frequency of rotation of the magnetic flux in the rotor windings, induced by harmonic signals (1), is added to the frequency of rotation of these windings. As a result, the frequency of the output voltage doubles. This voltage is measured by the registering device 5. Therefore, the emf from the induction coils 1 to the registering device 5 is transmitted without the use of a collector, which completely eliminates the error caused by the short-time opening of the contacts, thus increasing the accuracy. (/