Time: 20:00
Important one liner (PMMC Instrument)
- PMMC instruments use a permanent magnet and moving coil to measure DC accurately.
- High sensitivity in PMMC arises from many turns of fine insulated wire.
- A linear scale in PMMC simplifies direct current readings.
- Eddy current damping prevents pointer oscillations effectively.
- Jewel bearings reduce friction and enhance measurement precision.
- Alnico magnets offer stable, strong fields for consistent torque.
- Series resistors extend instrument range for higher voltages safely.
- Shunt resistors enable high-current measurement using PMMC ammeters.
- Phosphor bronze springs provide reliable controlling torque over lifespan.
- Litz wire coils minimize skin effect at higher frequencies for AC detection.
- Rectifiers convert AC to DC for PMMC-based alternating current measurement.
- Input impedance of PMMC voltmeters is high to reduce circuit loading.
- Temperature coefficients of coil wires impact reading accuracy under load.
- Torque sensitivity is quantified in newton-meters per ampere of current.
- Coil formers made from aluminum prevent magnetic distortion in PMMC.
- Permanent magnets may demagnetize if exposed to excessive temperature or shock.
- Calibration of PMMC instruments ensures correct deflection per unit current.
- Mechanical robustness makes PMMC suitable for portable electrical testing.
- High linearity reduces interpolation errors when reading scales.
- Low power consumption allows continuous monitoring with minimal energy loss.
- Compact design integrates easily into panel meters and instrumentation.
- Reading errors due to parallax are minimized with mirror-backed scales.
- Magnetic shielding protects PMMC from external field interference.
- Fine adjustment screws help zero the pointer before measurements begin.
- Easy-to-read pointers enhance user experience in rapid readings.
- Rigid coil support structures increase instrument durability under vibration.
- Advanced PMMC variants incorporate temperature compensation techniques.
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