Classification of electrical measurement instruments:

What are electrical measurement devices?

The devices used in electrical measurement of resistance or current, voltage, frequency, flux, power factor, etc. are called ’ Electrical measuring instruments’. Known as the ohmmeter, ammeter, voltmeter, frequency meter, flux meter, power factor meter, etc.

Classification of electrical measurement devices:

The electrical measurement quantities are used for the study and to test the electrical devices ’ efficiency. Such tools are available in analog or digital form.

In the electrical laboratory, analog meters are mostly used for practical studies, and digital meters are used for commercial, industrial and other purposes.

Electrical measuring instruments can be classified into different types:

Classification according to Electrical quantity:

There are two types:

  • Absolute instrument

  • Secondary instrument

Absolute Instruments:

Such instruments give the metric value of the electric quantity in terms of the constant and its deflection. Such devices are called’ Absolute Tools.’

It is also called Secondary or Indirect Instruments. Comparing these instruments with the standard values is not needed.

Secondary instruments:

These instruments give the value of the amount to be directly measured in the deflection.

Such instrument values are needed for comparison with the instruments ’ absolute or normal value.

Classification based on Electrical Supply:

Such instrument values are needed for comparison with the instruments ’ absolute or normal value.

  1. AC Instruments: The AC Instruments are connected with the AC supply
  2. DC Instruments: These instruments are connected with the DC supply.

Classification of Electrical Measuring Instruments according to the Effect

There are more chances of damaging the application or system due to the various magnetic effects, electromagnetic induction effects, electrostatic effects, thermal effects, chemical effects etc.

So, the multiple types of instruments are used to measure and compare the unknown quantities with the standard value. These instruments protect the device.

The classification is as follows.

  1. Moving Coil Instruments

  2. Moving Iron Instruments

  3. Induction Instruments

  4. Electrostatic Instruments

  5. Electrolytic Instruments

  6. Hot Wire Instruments

Classification according to Operation

Also the instruments can be classified according to the nature of the operation. We fell mainly into the secondary instruments.

These instruments are divided into four major parts.

  1. Indicating Instruments

  2. Recording Instruments

  3. Integrating Instruments

  4. Null Deflection instruments

Indicating Instruments:

The Indicating Instruments only shows the value of the electrical quantities per measuring time.

Only when attached to electrical supply do these instruments provide reading. Therefore, the location goes to zero.

Recording Instruments:

The measuring instruments show and report at the time of observations the reading of the electrical quantities.

Typically, these instruments are used in both the Generating Station and Substation.

Integrating Instruments:

The Integrating Instruments shows, records and applies at the time of readings the numerical value of interpreting the electrical quantities.

Null deflection instruments:

The Null Deflection Instruments display, at the time of readings, the reading of the electrical quantities without the deflection angle.