SU470766A1 - Automatic meter of effective capacitance and capacitance loss tangent - Google Patents

Description

one

This invention relates to radio engineering and is used in the manufacture of capacitors.

The known automatic meters of effective capacitance and loss tangent of capacitors, containing sources of constant and alternating voltage, connected to a capacitive divider consisting of an exemplary and measured capacitors, two channels of the system of automatic measurement of capacitance and loss tangent do not provide direct countdown.

In the proposed meter introduced serially connected model inductance and capacitor, which are connected in parallel to the measured capacitor and in series to the exemplary capacitor of the capacitive divider.

The drawing shows the functional diagram of the automatic meter.

The automatic meter of the effective capacitance and loss tangent of capacitors contains a source of constant voltage 1, which serves to supply a polarizing voltage to the measured capacitor, an alternator stabilizer 2, and a transformer 3 that supplies a certain voltage to the measuring circuit, a capacitive voltage divider consisting of an exemplary capacitor 4 and a test capacitor connected to

terminals 5, 6 parallel to the capacitor 7 and exemplary inductance 8, switch 9 and two channels of the system for automatic measurement of capacitance and loss tangent. The channel of automatic measurement of the loss angle tangent consists of two functional blocks, one of which is formed by the series connection of the input device 10, the amplifier limiting device 11, the pulse driver 12 and the delay unit 13, and the second by the input device 14, the amplifier 15 limiting device and the driver of pulses 16 A valve 17, a trigger 18, an integrating circuit 19, and a dial gauge 20 are connected to the outputs of both blocks. The input device 14 connected in series and the meter 21 constitute the channel for automatic measurement. and capacity.

The operation of the automatic meter of the effective capacitance and the loss tangent of the capacitor angle proceeds as follows.

When connected to the terminals 5, 6 of the tested capacitor, the value of the variable voltage across it, taking into account the conditions of the resonance, is determined by the ratio

with

Jarcig - x

f / i С

and., and,

V

HP

G. + S

30 where Ui is the voltage value of the supply circuit,

removed via switch 9 from the secondary winding of the transformer 3, Hz is the voltage taken from the output of the measuring circuit, Ho is the reactance

reference capacitor 4, Gx, Cx - parametQ

ry measured capacitor,) l arcs1§- -

x

phase shift between the voltage Hi and Uz, equal to the loss angle of the test capacitor. The voltage Uz is supplied through the input device 14 to the input of the meter 21, the scale of which is graduated in terms of the Cx eff. For measuring tg6x, where 6x is the offset angle between t / i and t / 2, the input voltage of the measuring circuit is fed to the input of the input device 10, and the input to the input device 14 is supplied with the voltage taken from the measured capacitor, the shape of which is converted from sinusoidal to rectangular. The delayed pulses from the output of the delay block 13 flip the trigger 18 to the state "1, and the positive edge of the generated signal from the output of the pulse former 16 through the valve 17 flips the trigger 18 to the state" O. As a result, a pulse is formed at the unit output of the trigger 18, the duration of which coincides with the phase shift between the input voltages Ui and t / 2. Valve 17 eliminates the possibility of a false signal. Average output voltage

the trigger 18 is proportional to the phase shift, therefore, from the output of the trigger 18, the voltage is applied to the integrator circuit 19, the output of which is connected to a dial device 20 with a scale graduated in terms of tg6x.

Subject invention

An automatic meter of effective capacitance and loss tangent of capacitors, containing sources of direct and alternating voltage, connected to a capacitive divider consisting of an exemplary and measured capacitor, two channels of the system for automatically measuring the capacitance and tangent of loss angle, characterized in that In order to obtain a direct reference, serially connected sample inductances and a capacitor are inserted into it, which are connected in parallel to the capacitor being measured and in series Capacitor splitter capacitor.