DC machine are main of two types which is Dc Generator & DC Motor.
Type of DC Machine
DC generator is rotated by a prime movers and produce electrical output in the form of dc voltage. So it convert mechanical energy into electrical energy.
DC motor receive energy from a DC voltage source and it convert in to mechanical output. So it convert Electrical energy in to mechanical energy.
figure shows the basic concept of dc gen. and dc motor.
Winding in DC machine
- In any DC machine there are two windings Field winding & Armature winding
- The field winding is stationary and Armature winding is a movable winding. Field winding may be separately excited or self-excite this is depend on the construction of dc machine. The armature winding is mounted on a shaft.
- The construction of a dc motor and dc generator is the same. That’s means we can use the same dc machine as a generator or as a motor.
Connection of DC Generator
- To operate the dc machine as a generator, the field winding is connected to the dc power supply and dc current start flowing through the field winding, this field winding is also called as stator winding (depending on the construction).
- Then the field winding produce an electromagnetic field in air gap between the armature and field winding (between stator and rotor).
- The armature winding is mounted on shaft and shaft is mechanically couple to another machine called prime mover. Then the load is connected to output armature winding connection.
Principal of Operation of DC Generator
Que. State working principle of DC generator.
- It working on a principle of dynamically induced EMF or electromagnetic
- According to this principle, if flux linked with a conductor is changed, then EMF is induced in conductor.
- The Value of the induced EMF is calculated by Faraday’s 2nd law of electromagnetic induction and the direction of induced current is given by Lenz law OR Fleming’s right hand rule.
- In case of generator, when armature winding is rotated by the prime mover, the flux linked with armature changes then an EMF is dynamically induced into armature
- This is the proper working principle of DC gen.