Thursday, November 6, 2008

Electrical Equipments

DC MOTOR
  • The Construction is similar with DC generator.
  • DC Generator act same as DC motor using a suitable potential through output terminal (DC motor act as DC generator but in reverse operation).
  • Operates based on the principle that a current carrying conductor placed in, and at right angles to, a magnetic field tends to move in a direction perpendicular to the magnetic lines of force (right-hand rule).

AC MOTOR

  • Mostly uses with constant speed in many applications (speed is depend on the frequency of every pole given).
  • AC motor mostly use synchronous 3- phase motor induction.
  • Rotor is a “cage” with conductors arranged in a cylinder with short circuited ends
    Rotor currents are supplied by electromagnetic induction, and a rotating magnetic field is established by 3-phase stator windings

BATTERY

Dry-cell batteries:

  • Cylinder container is made from zinc, carbon electrode and ammonium chloride as electrolyte.
  • Wet-cell batteries: Lead acid battery mostly use can be recharge with change and forced the electric direction.
Lead Acid Battery














TRANSFORMER

This equipment is used to transfer energy using electromagnetic induction.
Primary and secondary winding (between them is isolated) install in the apposite direction of ferromagnetic core.
Use for step up electric voltage (“step-up transformer”) or step down electric voltage (“stepdown transformer”)
Voltage is increased if the primary winding Voltage is raised when the primary winding has fewer turns than the secondary winding, and voltage is lowered when the primary winding has more turns than the secondary winding.

Simple Transformer










Practice:

Answer the question below:
1. Calculate value of V1, V2, V3, V4 and I!













2. Calculate the value of I1, I2, I3, I4 and total resistance of the circuit!


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