JP3012279U - Clamp type harmonic ammeter - Google Patents

Abstract

(57) [Summary] [Object] The object of the present invention is to eliminate the drawbacks of the conventional harmonic ammeter and to obtain a clamp type harmonic ammeter which is easy to use and can be accurately measured. [Structure] The CT core storage case 8 is attached to the tip of the main body case 1.
The main body case 1 is provided with a current value display section 3, a current value changeover switch 4, a power switch 5, a harmonic order setting switch 6, a data hold switch 7, and a recorder output 9,
It is connected by the main body circuit 2. Compact, lightweight and easy to use clamp type harmonic ammeter.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a clamp-type harmonic ammeter that is easy to carry and can accurately and accurately measure harmonic current in a field such as a cubicle in harmonic current measurement.

[0002]

[Prior art]

 Conventional harmonic ammeters separate the current transformer that detects the harmonic current and the measurement unit that analyzes the harmonics.The measurement unit also captures the harmonic waveforms at high speed and analyzes them with a computer. As a result, the power supply becomes large, and the peripheral circuit becomes complicated, resulting in a large shape, making it difficult to measure harmonics in the actual field. The price was also expensive.

[0003]

[Problems to be solved by the device]

 The object of the present invention is to eliminate the drawbacks of the conventional harmonic ammeter and to obtain a clamp type harmonic ammeter which is easy to use and can be accurately measured.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, this invention provides a CT core housing case at the tip of the main body case, and the circuit part uses an automatic tuning filter by an analog circuit to extract the current of only the set harmonic order. The circuit configuration is such that it can be driven by three AAA batteries.

[0005]

[Action]

 To measure the harmonic current of a cubicle using this device, turn on the power switch, press and pull the lever of the CT core storage case, open the CT storage case, and sandwich the target circuit. The current waveform converted by the CT core displays the current value up to the 23rd order by setting the harmonic order. When monitoring the set harmonic order for a long time, a recorder can be used together.

[0006]

【Example】

 An embodiment of the present invention will be described with reference to FIG. 1. Reference numeral 1 denotes a main body case in which a main body circuit 2 is inserted, and in the main body case 1, a current value display unit 3, a current value changeover switch 4, a power switch 5, A harmonic order setting switch 6, a data hold switch 7, and a recorder output 9 are provided and connected by the main circuit 2. Then, the current converted by the CT core is displayed by the harmonic order setting switch 6 on the current value display section 3 as a harmonic current value. The current value selector switch 4 changes the current value full scale.

A split type CT core housing case 8 made of synthetic resin or the like is provided at the tip of the main body case 1, and the CT core is housed in the CT core housing case 8. The CT core performs current conversion.

The current waveform input to the CT core will be described with reference to FIG. 3. The current waveform is converted into a voltage by the shunt resistor 12 and amplified to a signal level by the amplifier 13. Next, an automatic tuning filter is constructed by 14 switched-capacitor filters, 15 PLLs, and 16 control logic to extract harmonic components according to the fundamental wave, and 19 RMS-DC converter, 20 A / D The converter displays the current value of the set harmonic order.

The signal switching of 18 is to select a signal of a set harmonic order or a signal of all harmonic components, and when the current of all harmonic components is selected, the current of the true effective value indication is selected. Use as a total.

The recorder output of 22 is subjected to analog monitoring of harmonic current or effective current for a long time by a recorder or the like.

[0011]

EFFECTS OF THE INVENTION The present invention is configured as described above and is small and lightweight, so that harmonic current measurement in a cubicle or the like can be easily performed. Furthermore, since it is easy to handle, it is possible to safely measure the harmonic current even in a narrow space.

By using a plurality of the clamp type harmonic ammeters, the harmonic currents can be simultaneously measured under various conditions, so that the measurement efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of the present invention.

FIG. 2 is a side view of the present invention.

FIG. 3 is a circuit block diagram of a main body circuit.

[Explanation of symbols]

 1 Main body case 2 Main body circuit 3 Current value display section 4 Current value selector switch 5 Power switch 6 Harmonic order setting switch 7 Data hold switch 8 CT core storage case 9 Recorder output section 10 Dry battery storage section

Claims (2)

[Scope of utility model registration request] 1. A clamp type ammeter for measuring harmonics, wherein a CT core housing case 8 is provided at the tip of a main body case 1. 2. A circuit system for analyzing harmonic currents, wherein a switched capacitor filter 4, a PLL 5, and a control logic 6 constitute an automatic tuning filter to extract a harmonic current component of each order. Clamp type ammeter for wave measurement.