SU603911A1 - Electric testing instrument - Google Patents

Description

The invention relates to the field of instrumentation technology and can be used as an ordinance of an alternating voltage body and meter, as well as an instrument that allows to establish the integrity of consumer circuits and not to close them to the case (ground) when operating existing industrial plants. 1000V In accordance with the requirements of the safety technology. A test for the absence of voltage up to 1000 V is made by a voltage indicator (neon indicator) or a portable voltmeter, the use of warning lamps is allowed aets the linear voltage to 220. Immediately before checking for the absence of voltage, the pointer or other device used for this purpose must be in good condition on the current-carrying parts located nearby and which are obviously under voltage. If it is not possible to check the pointer or another device on the spot, they can be pre-checked on a non-disconnected area in another place. If the device was leveled, impacted or hit, it is prohibited to use it without re-checking. Known instrumentation devices include a rectifying bridge, the two arms of which form diodes, and the other two - the secondary windings of the transformer, while the dial indicator l is included in the diagonal of the bridge. The lack of known devices is low efficiency and safety of control of electrical circuits. To improve the efficiency and safety of control of electrical circuits, a control bridge containing a diode, two arms forming diodes, and two others - secondary windings of a transformer, a shooting indicator included in the bridge diagonal, a capacitor connected in series to the primary winding of a transformer DC source, comprising with a dial indicator a series circuit connected in parallel to the capacitor. The drawing shows a conceptual electrical cxei-a device. The control electrologyeter device contains the primary winding 1 of the transformer, which has a large impedance, a capacitor 2, the resistance of which is compared

with the transformer primary winding impedance is negligible / variable tuning resistor 3, which serves to set the device arrow to zero, DC source 4 / dial indicator 5, secondary windings 6/7 transformer / resistors 8, 9, diodes 10/11.

The device works as follows.

When the device connection terminals are short-circuited in a closed circuit from the positive electrode of the direct current source 4 through the indicator 5 / primary winding 1 of the transformer, having a relatively small resistance for the passage of direct current / and the alternating current source 4 to the negative electrode of the direct current source 4 current. In this case / if the variable resistor 3 is fully deduced / the arrow of the indicator 5 takes a position slightly to the right of zero. By changing the value of the variable resistor 3, the arrow is set to zero. After that, you can proceed to control the absence of voltage / voltage value or to measure the resistance within acceptable limits.

The operation of the device in monitoring voltage with a load is as follows.

When connecting the leads of the device to the source of alternating voltage in the absence of the most resistive arrow, the device should remain in the left extreme position or deviate slightly to the right / indicating the insulation resistance:, and / since disconnecting the voltage predetermines the line break / and allows the device not only to establish the absence of voltage / but also the disconnection of this installation from the secondary winding of the power transformer and generator.

Thus, / the double control of the absence of voltage and connection is carried out.

If there is a voltage / current on the current carrying parts, then a closed loop with an external resistance (with respect to, with a small value of) is formed for the source 4 of direct current and the instrument arrow should be set to zero. At the same time, alternating current from an external source will flow through the primary winding 1 of the transformer and through the capacitor 2. Due to the high impedance of the primary winding 1 and the insignificant resistance of the capacitor 2 compared to it, all the voltage drop is applied to the primary winding-1 of the transformer /

in the secondary windings 6/7, the proportional voltage is transformed / whose current / passage through the resistors 8/9 / is converted into a constant 10/11 diode and is added to the source current 4 / while the indicator arrow 5 deviates from zero to the left by the corresponding voltage angle.

In the absence of a controlled alternating voltage circuit, the proposed device operates as a probe or ohmmeter. In this case, the left (right) half of the indicator scale is used.

The use of the instrument allows the monitoring of alternating voltage / pre-production checking the integrity of the measuring circuit of the instrument and its operability. In the absence of voltage in a controlled circuit, the device allows to determine the integrity of the consumer circuits and the absence of their closure to the case (ground). Moreover, to switch from measuring to checking the integrity of the circuits, there is no need to perform any switching of the device / which ensures safe operation of electrical circuits / under voltage.

Claims (1)

1. Shkurin T.P. Handbook of Electric and Radio Measuring Instruments, Military Publishing. Ministry of Defense of the USSR / i960, p. 363.