What is dummy coil?

A dummy coil is a copper coil present in the armature of a DC machine which is used to reduce the effects of armature reaction on the air gap flux. This coil is not connected to the armature of the machine.

What is requirement of dummy coil?

Why they are required? – Quora. The dummy coils are used in some of the electrical machines wounded with wave winding. Its main purpose is to provide mechanical balance. With this image you will get better idea.

Why dummy coils are not used in lap winding?

Why dummy coils are not necessary in Lap winding? Because the lap winding is designed for any number of conductors.

What are the parts of a DC generator?

Parts of a DC Generator

• Stator. The main function of the stator is to provide magnetic fields where the coil spins.
• Rotor. A rotor in a DC machine includes slotted iron laminations with slots that are stacked to shape a cylindrical armature core.
• Armature Windings.
• Yoke.
• Poles.
• Pole Shoe.
• Commutator.
• Brushes.

What is the purpose of field coils in DC generator?

A field coil is an electromagnet used to generate a magnetic field in an electro-magnetic machine, typically a rotating electrical machine such as a motor or generator. It consists of a coil of wire through which a current flows.

What is the purpose of yoke in DC machine?

Yoke or the outer frame of DC generator serves two purposes, It holds the magnetic pole cores of the generator and acts as cover of the generator. It carries the magnetic field flux.In small generator, yoke are made of cast iron.

Why are dummy coils connected in dc machines?

The dummy coils are simply to provide mechanical balance for the armature. As they do not connect with commutator bars, they do not affect the electrical characteristics of the winding.

What are the six essential parts of a DC generator?

The key parts of DC generators are yoke, poles, pole shoes, armature core, armature winding, commutator, brushes, magnetic field system, commutator, end housings, bearings, and Shafts.

What is the purpose of field coil in DC generator?

How many coils does a generator have?

The three coils are equally spaced 120° apart around the inside of the stator. The armature coils are wired so that the generator has three separate output voltages that differ in phase by 1200.

Can DC machine work without yoke?

Construction of DC Machine. The construction of the DC machine can be done using some of the essential parts like Yoke, Pole core & pole shoes, Pole coil & field coil, Armature core, Armature winding otherwise conductor, commutator, brushes & bearings.