SU1644248A1 - Stand for testing electromagnet - Google Patents

Abstract

The invention relates to instrumentation technology and is intended to monitor the parameters of electromagnets (EM). The invention is an extension of the operational capabilities due to the expansion of the class of tested electromagnets and the simplification of the device, achieved by conducting tests in a quaistatic mode under a constant voltage supported by a voltage regulator. In this case, the electromagnetic force is determined by means of an analog computing circuit (ABC) by the formula "((U-2Ri) -i (J EM V -. Dt, where U, i, i V, R is the voltage, current, derivative of current, The speed and resistance of the winding of the electromagnet. To slow down the transient process, a liquid damper with an adjustable coefficient of viscous friction was used. The noted features significantly improve labor productivity and measurement accuracy, carry out tests of virtually any EM, obtain static and dynamic traction to evaluate the level of eddy currents and determine the response time of EM. 1 or i (L

Description

The invention relates to instrumentation technology and is intended to monitor the parameters of electromagnets (EM).

The purpose of the invention is to expand the operational capabilities by expanding the class of tested electromagnets, simplifying the device and increasing accuracy.

The drawing shows the structural scheme of the stand.

The stand contains a power source 1, a voltage regulator 2, a differentiating amplifier 3, a current sensor 4,

differential amplifier 5, multiplication unit 6, voltage sensor 7, dividing unit 8, speed sensor 9, integrators 10 and 11, liquid damper 12. The housing of the electromagnet 13 under study is mechanically connected with the stationary stand system (base), and its stem (measles) with the moving systems of the speed sensor 9 and the damper 12.

In the bench, an analog computational circuit (ABC) determines the electromagnetic force not by the formula of the prototype

with

Ј 4 № Ј

00

9V ,, fli.

"- ° .5" # - ҐЈ. (one)

valid only for electromagnets with an unsaturated magnetic system, and according to the universal formula

- -t (U - 2Ri) if

J j v

Em

dt, (2)

. I

where U, R, i, i, V are the voltage, the resistance of the EM winding, the current, the derivative of the current and the speed.

Expression (2) is obtained from the condition of constant voltage U const and active resistance R const, is universal and valid for any electromechanical converter (direct and alternating current with linear and angular displacements, etc.) and allows determination of Share electromagnetic force with high precision using standard, high-precision electronic devices. At the same time, the computational scheme is significantly simplified, since there is no need to determine the linkage and its partial derivatives with respect to displacement and current.

The device works as follows.

The electromagnet under investigation is mounted on a mounting plate, and its stem is mechanically connected to the moving speed sensor system 9. When static characteristics are removed, the movable system of the fluid damper 12 is connected to the moving system of the speed sensor 9. Under the force of gravity from the mass of the moving parts of the damper, the speed sensor and the electromagnet, the rod (measles) of the electromagnet is set to the position corresponding to the maximum working air gap . After that, the voltage is set at which the characteristics will be taken, the electromagnet winding is connected to the output of current sensor 4 and its mechanical system is braked by a latch (not shown in the diagram). Then, the voltage is applied to the winding of the electromagnet and zero voltages are set at the outputs of all electronic components. When disconnected

0

five

Q 5 "

Q, -

five

0

the lock rod of the electromagnet will move in the direction of reducing the working air gap. A change in movement, velocity, current, and electromagnetic force can be visualized by means of a storage oscilloscope or documented with a plotter or digital printing device. The speed - the movement of the rod is changed by adjusting the coefficient of viscous friction of the damper 12. When the dynamic characteristics are removed, the damper is disconnected.

If necessary, calibration is performed (the scale is determined) of the static traction characteristic of the electromagnet by means of calibrated masses connected to the mechanical output of the speed sensor. When the foot has reached the foot, the electromagnet is turned off by a limit switch (not shown in the diagram) and the rod (measles) returns to its original position. Then a new voltage value is set and the process is repeated. If a magnetoelectric transducer is used as a speed sensor, then with a resistive current sensor and an electronic current derivative sensor (with a filter), it is possible to measure electromagnetic force with an error not exceeding 1-2%.

In addition, the introduction of a liquid damper with an adjustable coefficient of liquid friction to the structural layout of the stand (for example, by changing the viscosity of the liquid or the section of the channel connecting the lower and upper cavities of the damper) makes it possible to determine in addition to the dynamic also static tractive characteristics and estimate the level of eddy currents in massive elements of EM structures. The presence of a tox derivative sensor allows automatic determination of the response time of the EM, if necessary.

Thus, the introduction of a voltage regulator, current sensors, voltage and speed sensors, a liquid damper with an adjustable coefficient of viscous friction, and a special analog computational scheme into the structural diagram allows one to determine the static and dynamic characteristics of electromagnets as if

with an unsaturated magnetic system, it will significantly (by a factor of 3–5) increase the accuracy of measuring electromagnetic forces and simplify the calculated circuit.

All this allows us to use the proposed stand not only for research of electromagnets, but also for assessing (controlling) their quality in the production process.

Claims (1)

Invention Formula An electromagnet test bench containing a power source, a differentiating unit, an amplifier, a multiplication unit, two integrators, and the fact that, in order to expand operational capabilities by expanding the class of tested electromagnets, simplifying the device and improving accuracy, a stabilizer is introduced into it voltage, current sensor, voltage sensor, dividing unit, speed sensor, liquid damper, a differentiating amplifier was used as a differentiating unit, and 0 five as an amplifier - differential - amplifier, while the output of the power source is connected to the input of a voltage regulator, the output of which is connected via a current sensor to the input of a differentiating amplifier, the first input of a differential amplifier, an input, a voltage sensor and a terminal for connecting the winding of the electromagnet under test, Thus, the output of the voltage sensor is connected to the second input of the differential amplifier, the output of which is connected to the first input of the multiplication unit, the second input of which is connected to the output of the differentiating device A speed sensor is installed with a kinematic connection with the movable element of the magnetic system of the electromagnet under test, the mechanical output of the speed sensor is connected to a liquid damper, and the electrical output is connected to the first integrator and the first input of the division unit, the second input of which is connected to the output of the multiplication unit and the output of the division unit is connected to the input of the second integrator.  bW