What are Electrodynamometer type instruments?

What are Electrodynamometer type instruments?

Electrodynamometer Instruments – Ammeter, Voltmeter and Wattmeter

  • Electrodynamometer or Electrodynamic instrument.
  • Electrodynamometer ammeter.
  • Electrodynamometer voltmeter.
  • Electrodynamometer wattmeter.
  • Basic Arrangement of an Electrodynamometer Wattmeter.

Why is an Electrodynamometer a transfer instrument?

These instruments have the same accuracy for both dc and ac. Explanation: Precision type electrodynamometer (EMMC) is used in the standardization process of the potentiometer and hence It is a transfer instrument.

What is the working principle of Electrodynamometer?

The Electrodynamometer wattmeter working principle is very simple and easy. It is based on the theory of a current-carrying conductor experiences a magnetic force when it is placed in a magnetic field. Hence there will be a deflection of pointer that took place due to the mechanical force.

What is Electrodynamometer how it is used as an ammeter and voltmeter?

An electrodynamometer type instrument is a moving coil instrument in which the operating field is produced by another coil which is fixed. This type of instrument can be used either as an ammeter or as a voltmeter, but is generally used as a wattmeter. ELECTRODYNAMIC INSTRUMENT AS AN AMMETER.

What are the advantages of Electrodynamometer?


  • Electrodynamometer instruments can be used for both AC and DC and voltage.
  • No sign of eddy current error and hysteresis error.
  • These instruments are very useful for accurate measurements of the RMS value of voltage irrespective of the waveform.
  • Dynamometer are precision grade instruments.

Which meter is suitable only for direct current measurements?

The basic moving coil meter is suitable only for direct current measurements, usually in the range of 10 μA to 100 mA. It is easily adapted to read heavier currents by using shunts (resistances in parallel with the basic movement) or to read voltage using series resistances known as multipliers.

What are the advantages and limitations of Electrodynamometer type wattmeter?

What are the advantages of electrodynamometer? As the instrument coils are air cared, so these instruments are free from hysteresis and eddy current errors. These instruments can be used on both a.c. and d.c. and since they have a precision grade accuracy, they are very useful as transfer instruments.

What types of voltmeters are used for DC measurements?

Electrostatic Voltmeter It works on the electrostatic principle where the repulsion between two charges plates deflect at a pointer attached to a spring. These instruments are used for high voltage AC and DC measurements.

What are the types of ammeters?

Type of Ammeter.

  • 1-Moving coil Ammeter.
  • 2-Moving magnet Ammeter.
  • 3-Electrodynamic Ammeter.
  • 4-Moving irom Ammeter.
  • 5-Hot wire Ammeter.
  • 6-Digital Ammeter.
  • 7-Integrating Ammeter.
  • What types of errors are occurred at Electrodynamometer wattmeter?

    Following are the errors in the electrodynamometer type wattmeters:

    • Errors in the pressure coil inductance.
    • Errors may be due to pressure coil capacitance.
    • Errors may be due to mutual inductance effects.
    • Errors may be due connections.
    • Error due to Eddy currents.
    • Errors caused by vibration of moving system.

    What is the full form of EMMC?

    An embedded MultiMediaCard (eMMC) is a small storage device made up of NAND flash memory and a simple storage controller.

    Which type of instrument can be used for DC?

    Permanent Magnet Moving Coil (PMMC) is only used for DC measurements. Moving Iron (MI) type instruments can be used for both AC & DC measurements.

    Which instrument is used for DC measurement?

    Multimeter is an instrument used to measure DC & AC voltages, DC & AC currents and resistances of several ranges. It is also called Electronic Multimeter or Voltage Ohm Meter (VOM).

    What is the limitations of Electrodynamometer type wattmeter?

    (i) They have a low torque/weight ratio and hence have a low sensitivity. (ii) Low torque/weight ratio gives increased frictional losses. (iii) They are more expensive than either the PMMC or the moving iron type instruments.

    What are different types of voltmeters?

    A voltmeter is an instrument used to measure voltage or electrical potential difference between two points in basic electric circuits….

    • Analog Voltmeters. Analog voltmeter includes deflecting type of indicating voltmeters.
    • VTVMs and FET-VMs. Vacuum Tube Volt Meter (VTVM)
    • Digital Voltmeters.

    What are the two types of voltmeters?

    Based on the construction principle: Moving Iron Voltmeter: There are two types of moving iron voltmeter, and they are attraction type and repulsion type.

    What is the meaning of Milliammeter?

    noun. an instrument for measuring small electric currents, calibrated in milliamperes.

    What kind of instrument is an ammeter?

    An ammeter (abbreviation of Ampere meter) is a measuring instrument used to measure the current in a circuit. Electric currents are measured in Amperes (A), hence the name. The ammeter is usually connected in series with the circuit in which the current is to be measured.

    What type of scales and pointer is used for Electrodynamometer wattmeter?

    Dynamometer instrument can be used as Ammeter, Voltmeter, and Wattmeter. But it is more effective in the Wattmeter type because power is proportional to the square of the current. The scale is uniform in the Wattmeter type.

    What are electrodynamometer type instruments?

    Electrodynamometer type instruments are used as a.c voltmeters and ammeters both in the range of power frequencies and lower part of the audio frequency range. They are used as watt-meters,varmeters and with some modification as power factor meters and frequency meters. Operation Principle of Electrodynamometer type instrument:

    What is a directdynamometer type wattmeter?

    Dynamometer Type Wattmeter is similar to the dynamometer type ammeters and voltmeters. The dynamometer instruments are used more as wattmeters, as they are expensive (Fig. 1.). The fixed coil which is divided into two equal coils is used as ‘”current coil (CC) ” and the moving coil is used as a “pressure coil (PC).

    What is the working principle of an electrodynamometer?

    We can have an idea of the working principle of the electrodynamometer instrument by taking up a permanent magnet moving coil instrument and considering how it would behave on AC. It would have torque in one direction during one half of the cycle and an equal effect in the opposite direction during the other half of the cycle.

    What are the types of coils present in an electrodynamometer?

    There are two types of coils present in the electrodynamometer. They are : Moving coil moves the pointer with the help of spring control instrument. Limited of current flows through the moving coil so as to avoid heating. So in order to limit the current we have connected the high value resistor in series with the moving coil.