SU941056A1 - Ferroprobe transducer for tracking butt of parts being welded - Google Patents

Description

A filter and a feedback circuit filter, a magnetic zero input unit, is made in the form of two current collectors located symmetrically with respect to the joint, the current collectors are connected in parallel with each other and to one of the power supply terminals, and the ferrosonde is installed directly on the welding head.

FIG. Figures 1 and 2 show the block diagram of the device proposed for two cases of electrode deflection from the junction, respectively, to the right and to the left.

The fluxgate sensor contains a source, 1 welding current, a magnetic zero input unit and a magnetic field register | The input unit of the magnetic field is made in the form of two current collectors 2 and 3, fixed symmetrically with respect to the arc gap and the butt 4 on the parts to be welded 5 b and connected in parallel to the welding current pell 7. The magnetic nol registration unit is composed of a differential ferrosonde 8 fixed on the welding the head 9 above the welded section of the junction 4, the amplifier-converting path and the feedback circuit. Differential ferrosonde 8 contains two permalloy cores, an excitation winding 10, an output winding 11, a compensation winding 12. The excitation winding 10 is connected to the master oscillator 13 via a frequency divider 14 by two. Amplifying-transforming path contains a series of connected selective amplifier 15, tuned to resonance at frequency 2 of driver oscillator 13 and having a bandwidth that captures side frequencies 2 (oo-f S and 2 cdo-Q (And often the welding volume-7), phase discriminator 16, receiving the reference voltage from the master oscillator 13, the selective amplifier 17 tuned to the Q frequency, phase discrimination discriminator 18, the reference input of which is connected to the welding current source 1, and a smoothing filter 19. Reverse circuit connection is composed of a feedback filter 20, B1: switched between the output of the phase discriminator 16 and the compensation band of the fluxgate 8.

During the welding process, the welding current 7, supplied from the source 1 of the welding TOKia to the electrode 21, is divided into two components 22 and 23, which induce magnetic fields 24 and 25 over the parts 5 and 6 to be welded.

When the electrode 21 is positioned exactly above the junction 4, the components 22 and 23 of the welding current do not flow through the current section 4. Ferro probe 8 is installed at the welded section of the joint in such a way that it reacts to the magnetic loop of the current flowing through the welded section 4 and does not react on

the magnetic fields of the current in the electrode 21 and the parts to be welded are 5 and 6. For this, the sensitivity axis of the fluxgate 8 is oreitized in a plane passing through the electrode 18 parallel to the junction 4. Therefore, the projection of the magnetic field from the welding current and the welded junction of the fluxgate 8 is equal to zero when the electrode is aligned with the junction 4 and the electrical output signal of the differential fluxgate 8 is absent.

When the electrode 21 deviates from the junction 4 (see Fig. 1), the welding current component 23 flows through the welded section of the junction 4 and the projection of the magnetic field 25 on the sensitivity axis of the differential ferrosonde 8 characterizes the magnitude and direction of the electrode 25 deviation from the joint 4. Under the action This Projection of induction in the output winding of the fluxgate 8 is induced by the second harmonic of the form:

/ 2 l:. () So5 (2sho-Q) -

- {2u) o-fQ) cos (2coo + Q) /,

where X is the displacement of the electrode from the joint;

k is a coefficient proportional to p,

The output signal of the differential flux probe 8 is amplified and converted by selective amplifiers 12 and 14 and phase discriminators 15 and 18 into a DC voltage proportional to the displacement of the electrode 21 from the junction 4 of the parts 5 and 6 being welded. Pulsors in the output voltage are suppressed by a smoothing filter 19.

When the electrode 21 deviates from the junction 4 in the opposite direction (see Fig. 2), a welding current component 22 and a projection of the magnetic field 24 onto the axis 24 flow through the welded section.

The sensitivity of the fluxgate 8 has the opposite direction. In this case, in the output winding of the fluxgate 8, a second voltage will be induced (harmonics of the form:

Hz X. D (2ао-Q) cos (2coo -) / -

- (2coo + Q) cos (2a) o +) /.

Amplifier circuit forms a DC voltage,

proportional to the displacement of the electrode 2 from the junction 4, but of opposite polarity.

The feedback circuit of the fluxgate sensor automatically coaxes the external magnetic fields in the fluxgate volume 8, which is achieved by passing the compensation current from the feedback filter 20 through the compensation winding of the fluxgate 8, the frequency characteristic of which is selected in such a way that it automatically compensates. only permanent external magnetic fields.

The use of the proposed fluxgate sensor permits an increase in the accuracy of the direction of the electrode along the junction of arc welding due to the elimination of the error associated with the leading position of the sensor 1a relative to the welding electrode. This is due to the fact that the proposed flux probe sensor intends to directly deviate the electrode from the joint of the welded parts and not to deviate the sensor from the joint as in the prototype.

Claims (2)

1. USSR author's certificate Afb 478698, cl. B 23 K 9 / .10, 04/02/73. 2. USSR author's certificate No. 499069, 1СЛ. At 23 K 9/10, 04.02.74.