pmmc instrument work only DC but not use ac ,why?

pmmc instrument

• Rocky
• 36160 दृश्य
• 2 उत्तर

• because pmmc instruments measure- avarage value and avarage value of a.c is zero so that ,pmmc Meter's pointer does not move.

  • Vijay
  • 16 नवम्बर
  • 0 टिप्पणी

  1

  ---

• PMMC- permanent magnet moving coil instrumentbr /PMMC type instrument uses two permanent magnets in order to create stationary magnetic field. These types of instruments are only used for measuring the DC quantities as if we apply AC current to these type of instruments the direction of current will be reversed during negative half cycle and hence the direction of torque will also be reversed which gives average value of torque zero. The pointer will not deflect due to high frequency from its mean position showing zero reading. However it can measure the direct current very accurately.

  • Shreya
  • 06 जून
  • 0 टिप्पणी

  1

  ---

• bridge bonding
• Materials with lots of free electrons are called
• in an alternater at what power factor the effect armature reaction is de-magnetizing....
• Transformer efficiency changes by reversing its terminals
• capacitor
• I want to apply in University of Washington Electrical Engineering. Do I need an undergraduate degree in Electrical Engineering to apply?