JP2536668Y2 - Clamp type measuring instrument - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamp-type measuring device for measuring a current or the like by clamping a sensor on an electric circuit to be measured. More specifically, a clamp sensor of the clamp-type measuring device is connected to a coil on a primary side of a clamp adapter. The present invention relates to a clamp-type measuring device that can be used as a device.

[0002]

2. Description of the Related Art A clamp-type measuring instrument detects a current flowing therethrough in a live state without connecting an electric circuit to be measured, and performs a predetermined operation based on the current value, thereby obtaining an electric circuit to be measured. Because it can measure the current, voltage, power factor, etc., it is provided as a clamp ammeter, clamp voltmeter, or clamp power factor meter. In such a clamp-type measuring instrument, measurement can be performed in several ranges by switching ranges. Therefore, the user purchases and uses a desired type of clamp-type measuring instrument having a range that is relatively frequently used, but sometimes a current of a value higher than the rating of the clamp-type measuring instrument that the user owns is used. In some cases, it may be necessary to perform measurement, or the diameter of the electric circuit to be clamped may be so large that the clamp sensor of the measuring instrument may not be clamped even if the clamp sensor is fully opened. Also, in such a clamp-type measuring instrument, it is impossible to measure from a small current to a large current with the same clamp sensor due to the problem of magnetic saturation of the clamp core. An arm is required and cannot be opened and closed.

Therefore, a pair of clamp arms each having a coil wound around a core made of a magnetic material are housed as an adapter of a clamp type measuring instrument, and a primary coil having one end of each of these clamp arms pivotally supported, and a ring. There is provided a clamp adapter in which a secondary coil having a coil wound around a core made of a magnetic material is connected by a cable. Here, assuming that the current to be measured is I, the secondary current is i, the number of turns of the primary coil is N1, and the number of turns of the secondary coil is N2, the secondary current i is I / N1. The generated current is i × N2 = (N2 / N1)
× I, the measured current value can be changed at an arbitrary ratio by changing the turns ratio between the primary coil and the secondary coil. For example, if the turns ratio between the primary coil and the secondary coil is set to 10: 1, a measured current of 1/10 appears on the secondary coil side. Therefore, by clamping the clamp-type measuring device on the secondary coil side, the measurement can be performed up to the indicated value × 10 times, and the measurement range can be expanded. If the turns ratio between the primary coil and the secondary coil is set to 1:10, the current sensitivity can be increased by a factor of 10, and a small current can be measured. Furthermore, if the turns ratio between the primary coil and the secondary coil is set to 1: 1 and the clamp diameter of the primary coil is increased, the current value of the large-diameter electric circuit to be measured that cannot be clamped by the clamp-type measuring instrument can be reduced. It can be measured in the live state. Since such an adapter has a simple structure including only the primary and secondary coils and a case that covers them, it is possible to provide a large-diameter adapter for a large current.

[0004]

As described above, attention is paid to the fact that the clamp sensor of such a clamp-type measuring device detects the current value of the electric circuit to be measured and has a range switching function. By switching the range, the clamp sensor of the clamp-type measuring device can be used as the primary coil of the clamp adapter, so if you have multiple clamp-type measuring devices, you do not need to prepare a new clamp adapter. Another object of the present invention is to provide a clamp-type measuring instrument capable of measuring a range other than the measuring range of the clamp-type measuring instrument to be used.

[0005]

The clamp-type measuring instrument of the present invention selectively connects a coil of the clamp sensor to a coil of the clamp sensor by switching a range changeover switch, and has a secondary coil having a different winding ratio from the coil of the clamp sensor. The secondary coil is characterized in that it can be clamped to a clamp sensor of another clamp-type measuring instrument.

[0006]

[Function] The range switch is switched to the clamp adapter side, the clamp sensor is clamped to the electric circuit to be measured, and the secondary coil is clamped to the clamp sensor of another clamp type measuring instrument, so that the coil of the clamp sensor is used as the primary coil. The current value can be lowered or raised according to the turns ratio with the secondary coil, and if the current value is detected by the clamp sensor of another clamp-type measuring device, it can be used outside the measuring range of the measuring device. Can be measured.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment shown in the drawings will be described below, taking as an example the case where the present invention is applied to a clamp-type ammeter. First, a first embodiment shown in FIGS. 1 and 2 will be described. This clamp type ammeter has a case body 1 in which a measuring circuit and the like are housed, and one end of the case body 1
Clamp arms 2 and 3 pivotally supported by
And an operation knob 4 that protrudes from the side of the case body 1 and presses inward to open the other ends of the clamp arms 2 and 3. A rotary knob 5 for range switching is attached to the case body 1. Each of the clamp arms 2 and 3 is configured by winding a coil 8 around a magnetic core 7 inside an arm case 6. The measurement data is output to a recorder (not shown) via the code 9 and the plug 10. As shown in FIG. 2, a rotary switch 11 switched by a rotary knob 5, a shunt resistor 12 for converting a current detected by a coil 8 into a voltage corresponding to each range, and a plug 1
Resistance 13 for output adjustment to recorder or the like connected to 0
Is provided. These components are the same as those of the conventional clamp-type ammeter, and detailed description thereof will be omitted.

The plug 10 is mounted on the side of an adapter case 15 having a secondary coil 14 of a clamp adapter therein. The secondary coil 14 is wound in a ring shape, and the adapter case 15 is also formed in a ring shape, and is configured such that a clamp sensor of another clamp-type ammeter can be clamped at the opening in the ring shape. By setting the number of turns of the secondary coil 14 to the number of turns of the coil 8, for example, 1:10, the current of the coil 8 can be reduced to one tenth. The secondary coil 14 is connected to the coil 8 via a switching terminal not used for switching the range of the rotary switch 11. Therefore,
A mark 16 indicating the position of the rotary knob 5 when used as a clamp adapter is written on the case body 1 together with the indication of range switching.

Therefore, when used as an ordinary clamp-type ammeter, the range in which the current value of the electric circuit to be measured enters is set by adjusting the rotary knob 5 and the measured object is set in the clamp arms 2 and 3. If an electric circuit is interposed, the data of the measured current value can be output from the plug 10 to a recorder or the like as in the related art. On the other hand, when this clamp-type ammeter is used as a clamp adapter, the position of the rotary knob 5 is adjusted to the mark 16 and the clamp sensor of another clamp-type ammeter is clamped to the adapter case 15 so that the clamp arm 2, By interposing the electric circuit to be measured in 3, the current value of the electric circuit to be measured can be reduced to one tenth and output to the clamp sensor of another clamp-type ammeter.

In a second embodiment shown in FIG. 3, a secondary coil of a clamp adapter is integrally provided on a case body 1. That is, a cover 22 having an opening 21 formed therein is integrally formed at an end of the case body 1 facing the clamp arms 2 and 3, and the above-described secondary coil 14 is housed therein. Things. Except that the secondary coil 14 is provided on the case body 1, the structure is the same as that of the first embodiment.

In the above embodiments, the clamp type ammeter has been described as an example. However, a clamp voltmeter or a clamp power factor meter having a range switching mechanism has a similar configuration using the coil of the clamp sensor unit. Then, it can be used as a clamp adapter. Since there is a possibility that the secondary coil 14 side may be opened at the time of switching, it is preferable to use a shorting type rotary switch 11.

[0012]

As described above, the clamp type measuring device of the present invention selectively connects the coil of the clamp sensor to the coil of the clamp sensor by switching the range changeover switch, and the secondary coil having a different winding ratio from the coil of the clamp sensor. The secondary coil is clamped by a clamp sensor of another clamp-type measuring instrument, so that the coil of the clamp sensor is used as the primary coil, and the current value is determined according to the turns ratio between the primary coil and the secondary coil. It can be transmitted to the clamp sensor of another clamp-type measuring instrument by being lowered or raised and lowered, and can be measured even outside the measuring range of the measuring instrument. Therefore, if a plurality of clamp-type measuring devices are provided, it is possible to measure electrical characteristics outside the measuring range of the measuring device without newly obtaining a conventional clamp adapter.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram illustrating an electrical configuration of a detection unit and a switching unit according to the first embodiment.

FIG. 3 is a perspective view showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case main body 2, 3 Clamp arm 4 Operation knob 5 Rotary knob 8 Coil 11 Rotary switch 14 Secondary coil 16 Mark

Claims (1)

(57) [Scope of request for utility model registration] 1. A clamp-type measuring instrument with a range changeover switch that includes a pair of openable and closable clamp sensors, and measures an electric characteristic of the measured electric circuit by locating the measured electric circuit in the clamp sensors. The clamp sensor is selectively connected to the coil of the clamp sensor by switching the range changeover switch, and includes a secondary coil having a different turn ratio from the coil of the clamp sensor, and the secondary coil is a clamp of another clamp-type measuring device. A clamp-type measuring device configured to be clampable to a sensor.