Why field winding is not excited by AC in DC machine?

So if we give AC supply the pole created in the rotor winding will be alternating and it not be created any magnetic locking with the stator field. So if we give AC supply, the rotor will stop rotating after removing the prime mover. This was the reason Why DC is used not AC for excitation of Synchronous Motor.

What will happen if AC supply is given to DC motor?

As the motor is DC so the field and armature winding made for DC supply. The winding which is made for DC always has more resistance than the winding which is made for AC. For this reason, the motor will be run in very less speed on AC supply. When DC motor Runs on AC supply more loss and heat will occur in the motor.

Which supply is given to field winding of DC?

The field winding, which produces the constant magnetic field in the stator, is wired in parallel, or in shunt, with the armature windings in shunt DC motors. The same power supply is therefore used to power both the armature and the field windings, and the total current is split into two parallel paths.

Why AC is not used for excitation?

While in case of AC it will produces variable and rotating( for 3 phase supply) magnetic field as well as pole and therefore output voltage would not have fixed frequency and magnituted too. Thats why ac is not for excitation.

What happen if field winding of running DC shunt motor is suddenly break?

If field winding is disconnected accidentally, the speed would dangerously increase in order to maintain the back emf of the motor.

Which part will surely tell that given motor is DC motor and not an AC type?

Commutator
Commutator will surely tell that given motor is DC motor and not an AC type. 3.

What happens if field winding of synchronous machine is excited by AC?

As the Field Winding is excited by AC source, an alternating / pulsating magnetic flux will be produced. The armature conductor at Stator will not see any change in flux due to backward rotating field flux and hence no EMF will be generated in the Armature Terminal of Alternator.

Why is DC excitation given?

Why only D.C is used for Excitation in Alternators? Excitation voltage or current is supplied to the field windings of a rotor to produce a static magnetic field. If we use alternating current instead of direct current; we will get a fluctuating magnetic field.

How does AC machine differ from DC machine?

The most basic difference is the power source. A.C. motors are powered from alternating current (A.C.) while D.C. motors are powered from direct current (D.C.), such as batteries, D.C. power supplies or an AC-to-DC power converter.

What is the function of field winding in DC machine?

field winding in Electrical Engineering A field winding is the insulated current-carrying coils on a field magnet that produce the magnetic field needed to excite a generator or motor. As each coil is energized in turn, the rotor aligns itself with the magnetic field produced by the energized field winding.

What happens when DC supply is given to an alternator?

In alternator the rotor part constitutes field winding so if we give DC supply to field winding constant field is developed and we make the rotor rotate so that flux will be rotated and it cuts the conductors in stator and emf is induced in the armature winding.

Why DC is used not AC for excitation of synchronous motor?

So if we give AC supply, the rotor will stop rotating after removing the prime mover. This was the reason Why DC is used not AC for excitation of Synchronous Motor. Why DC is used instead of AC for excitation of Synchronous Alternator?

What is the difference between armature and field winding in alternator?

Generally, In a DC machine armature is placed in the rotor and field winding placed in the stator that means in DC machine Armature is the rotating part and main filed winding is the static part. But in the case of three phase alternator Armature is the static part and the main field is the rotating part.

What is the difference between static armature winding and main field winding?

In the synchronous motor also, armature winding is the static part and main field winding is the rotating part of the machine. To operate the synchronous motor we have to need to give the main ac supply to the static armature winding and an auxiliary DC supply to the rotating field winding.