Different Types Of Losses In Electrical Machines, AC, DC Motors

May 8, 2021October 22, 2022 Abhiraj

Hello guys, welcome back to our blog. In this article, we will discuss the different types of losses in electrical machines, AC motors, DC motors, losses in the transformer, static machine losses, and rotating machine losses.

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Losses In Electrical Machines

Electrical machines are mainly of two types: 1. Static Machines 2.Rotating machines. So there will be some losses due to the involvement of electromagnetic induction effects and rotating parts. The losses will decrease the efficiency of the machines. The main key to improving efficiency is to decrease losses. Now let us see about different types of losses in electrical machines.

Static Machine Losses

The machines which do not contain any rotating parts are called static machines. There are mainly two types of stationary machines: Single phase transformers and three-phase transformers. The transformer also comes under the AC machine but it is a static ac machine. Let us see the losses in the transformer.

Transformer losses

There are mainly four types of losses in transformers:

01. Iron losses: The losses caused by the alternating flux in the core of the transformer are called iron losses. It is further divided into two types.

a. Hysteresis losses: The losses that occur because of the variation of the magnetization in the core of the transformer are called Hysteresis losses.

b. Eddy current losses: The circulating small currents in the core of the transformer are called eddy currents. Eddy currents are not responsible for doing any useful work and they cause losses due to magnetic material those losses are called eddy current losses.

02. Copper losses: The losses that occur because of transformer winding resistance is called copper losses. It is given by? = ?^2 * R.

03. Stray loss: The loss that occurred due to the leakage flux from the core is called Stray loss.

04. Dielectric loss: The loss caused due to the failure or damage of insulating material is called dielectric loss such as the deterioration of oil and the damage of solid insulators.

Rotating Machine Losses

The machines which contain rotating parts are called rotating machines. Due to the presence of rotating parts the losses are comparatively high than the static machine. These are mainly classified into two types such as DC machines and Ac machines. AC machines also contain a transformer that comes under the static machines. Let us see the losses in dc and ac machines,

DC Machine Losses

The machines which run on DC supply are called DC machines. The losses in dc machines are mainly divided into five types:

01. Copper losses: The losses caused due to the ohmic resistance of windings in the machine are called copper losses. There are mainly two types of windings in the dc machine such as armature and field windings. The copper losses are universally given by the equation: P = I^2 * R The values will be changed with the respective windings.

02. Core losses: The losses that occurred due to constant flux density in the core are called core losses. These losses are the addition to both hysteresis and eddy current losses.

03. Brush losses: The power loss between the commutator and carbon brushes is called brush loss. It is popularly known as Brush contact loss. The equation of brush loss is given as, P = EI.

04. Mechanical losses: The losses that occurred due to the mechanical effects in the machine are called mechanical losses. These losses are classified into two types such as friction and windage losses. In the presence of rotating machines, there will be tearing or corrosion of machines to prevent the mechanical losses bearings are used.

05. Stray losses: The losses that occurred because of armature reaction and short circuit currents in the coil are called stray losses. The distortion of flux due to the armature reaction is the main factor for stray loss.

AC Machine Losses

The machines which run on ac supply are called AC machines. The rotating machines in ac supply are called AC motors. The losses in ac motors are mainly classified into two types:

01. Constant losses: The losses which are constant all the time in the machine are called constant losses. These losses are further divided as:

a. Core losses: The losses that occurred due to constant flux density in the core are called core losses. These losses are the addition to both hysteresis and eddy current losses.

b. Mechanical losses: The losses that occurred due to rotating parts are called mechanical losses. These losses change according to the speed of the motor. These losses are classified into two types such as friction and windage losses.

c. Brush Friction losses: The losses occurred due to the tearing between the brushes.

02. Variable losses: These losses are also called copper losses. This is because of the current passage through stator and rotor windings. The blocked rotor test is conducted to know the copper losses of the motor. These losses are classified as Stator copper loss and rotor copper loss. These copper losses will change with the change of current.

Losses are also considered as the key point because the efficiency of the machines is dependent on the losses in the Electrical machines. I hope this article may help you all a lot. Thank you for reading.

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