JPS58109860A - Measuring device of insulation resistance - Google Patents

Abstract

PURPOSE:To reduce the power consumption as well as the faults due to the generation of heat, by providing a current detecting circuit and delivering a signal when a current higher than the set level flows to hold it at a sample holding circuit. CONSTITUTION:The high voltage is applied to measuring terminals 5 and 5 via a boosting circuit 3 and a rectifying circuit 4. In this case, no current flows if an object 10 to be measured has high insulating performance, and therefore a current detecting circuit 6 delivers no signal. When the insulating performance of the object 10 is low and a current flows, the circuit 6 delivers a signal. This state is held by a sample holding circuit and displayed at a display 9. Thus the output voltage of the circuit 6 is held by the sample holding circuit and then displayed at a display like a voltmeter, etc. This can reduce the power consumption as well as the troubles due to the generation of heat.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulation resistance measuring device that measures insulation resistance by applying a high voltage to an object to be measured.

In general, this moderate insulation resistance measuring device continuously generates a high voltage in an external pressure circuit, applies this high voltage to the object under test, and detects the flowing current. Since high voltage is continuously generated, the current consumption increases and there is a risk that the electrical components of the booster circuit will heat up and break down.In view of the above points, the present invention aims to reduce the current consumption. This is also aimed at reducing the number of failures in the booster circuit.

The present invention will be explained below based on the drawings showing one embodiment of the present invention. Reference numeral 1 denotes an oscillation circuit that outputs a pulse signal. 2 is a synchronous oscillation circuit which outputs a signal for a longer time than the output signal in synchronization with the output signal of the oscillation circuit 1.03 is an external pressure circuit which outputs an oscillation output signal as shown in FIG. The voltage is boosted in response to the output signal of the synchronous oscillation circuit 2. In the embodiment, the push nibble circuit operates in response to the output signal of the synchronous oscillation circuit 2, causing the primary current to flow through the step-up transformer and extracting the secondary output voltage. o4 is a rectifier circuit, and the step-up circuit 3 The output voltage of is rectified and applied to a constant terminal 5.5. Reference numeral 6 denotes a current detection circuit, which detects the current flowing through the measurement terminal 5.5 through the rectifier circuit 4. In the embodiment, a signal is output when this current exceeds a set value. A delay circuit 7 delays the output signal of the oscillation circuit 1 by a certain period of time and outputs the delayed signal. This fixed delay time is set to a time that stabilizes the measurement within the output time of the synchronous oscillation circuit 2.Of course, the oscillation circuit 1
The pulse width of the output signal of the delay circuit 7 may be different from the pulse width of the delay circuit 7. Reference numeral 08 is a gun pull hold circuit which inputs the output signal of the delay circuit 7 and the output signal of the current detection circuit 6; When there is no output signal of the delay circuit 7, the input of the output signal of the current detection circuit 6 is prohibited, and when there is an output signal of the delay circuit 7, the inhibition of input of the output signal of the current detection circuit 6 is released and this output signal is input. and to keep it. 9 is bell,
A display device such as a buzzer or a light-emitting element, which displays the nine signals held by the sample-and-hold circuit 8. Figure 2 shows the operating characteristics of Figure 1, and (a) shows the output of the oscillation circuit 1. signal, (the output signal of the synchronous oscillation circuit 2, (
C) is the output voltage of the rectifier circuit 4, (d) is the current detection circuit 6
, (e) shows the output signal of the delay circuit 7, and (f) shows the output signal of the sample and hold circuit 8. To explain this operating state, when the oscillation circuit 1 outputs a signal, this A synchronous oscillation circuit 2 operates for a predetermined period of time in synchronization with the signal, and a measurement terminal 5 is generated via an external pressure circuit 3 and a rectifier circuit 4.
．． Apply high pressure to 5. At this time, if the insulation of the vagina of the object to be measured is good, no current will flow and the current detection circuit 6 will not output a signal.In addition, a signal may be output due to an initial transient phenomenon due to stray capacitance between the measurement terminals 5 and 5. However, due to the delay of the delay circuit 7, it is ignored. Therefore, the sample hold circuit 8 maintains a state in which there is no signal from the current detection circuit 6, and this state is displayed on the display device 9. Furthermore, if the insulation of the vagina of the object to be measured is poor and a current flows, the current detection circuit 6 outputs a signal, and the sample and hold circuit holds this state and displays it on the display device 9.

In the embodiment, the current detection circuit 9 outputs a signal when a current exceeding a set value flows, but it is also possible to output a voltage corresponding to the flowing current value and use the sample and hold circuit to output the voltage. Display device 9 such as voltmeter, ammeter, etc.
It may also be displayed in

Thus, the present invention provides an oscillation circuit 1 that outputs a pulse signal, a synchronous oscillation circuit 2 that outputs a signal for a longer time than the output signal in synchronization with the output signal of this oscillation circuit 1, and this synchronous oscillation circuit 2. a rectifier circuit 4 that rectifies the output voltage of the booster circuit 3 and applies this rectified voltage to the measurement terminal 5.5; A current detection circuit 6 that detects the current flowing through the Ilj constant terminal 5.5, a delay circuit 7 that delays the output signal of the oscillation circuit 1 by a certain period of time, and outputs the output signal after delaying the output signal of the oscillation circuit 1 for a certain period of time;
The sample-and-hold circuit 8 releases the input inhibition when outputting the current detection circuit 6, inputs the output signal of the current detection circuit 6, and holds this input signal, and the display device 9 displays the signal held by the sample-and-hold circuit 8. Therefore, compared to the conventional type that continuously generates high voltage, the current consumption is lower, and electrical parts such as the booster circuit 3 generate less heat, which reduces failures. is applied to the measurement terminal 5.5, and after a certain time delay, the sample and hold circuit 8
Since the inhibition of input to the current detection circuit 6 is lifted, there is an effect that measurement can be carried out at a stable point without being affected by initial transient phenomena, noise, surges, etc.

[Brief explanation of the drawing]

Drawing #1 is a circuit block diagram showing an embodiment of the insulation resistance measuring device of the present invention, and FIG. 2 is an operating characteristic diagram of the main part of FIG. 1. 0 1...Oscillation circuit, 2-... Synchronous oscillation circuit % 3... Boost circuit, 4... Rectifier circuit % 5.5... Measurement terminal,
6...Current detection circuit, 7.es delay delay circuit 8...Sample hold circuit, 9...Display position 0 Fig. 1 Fig. 2 1□-''=

Claims (1)

[Claims] (1) An oscillating clock that outputs a pulse signal, a synchronous oscillation circuit that synchronizes with the output signal of this oscillation circuit and outputs a time signal longer than this output signal, and a synchronous oscillation circuit that responds to the output signal of this synchronous oscillation circuit. an external pressure circuit that boosts the voltage; a rectifier circuit that rectifies the output voltage of the booster circuit and applies the rectified voltage to the measurement terminal; a current detection circuit that detects the current flowing from the rectification circuit to the measurement terminal; and the oscillation circuit. a delay circuit that delays the output signal of the current detection circuit for a certain period of time and outputs the output signal; a sample hold circuit that inputs the output signal of the current detection circuit and holds the input signal; An insulation resistance measuring device consisting of a display device that displays the signal held by a sample and hold circuit.