How can you improve the design of a DC machine?
Increased Poles & Conductors
Realistic designs for dc machines usually have more than 2 poles. Increasing the number of poles for a particular flux per pole will increase the induced voltage at a given speed and increase the torque available per amp.
What is the efficiency of DC machine?
Order of efficiency of rotating d.c machine is about 80 % to 85 %. It is therefore important to identify the losses which make efficiency poor.
What is the principle of DC machine?
The working principle of a DC machine is when electric current flows through a coil within a magnetic field, and then the magnetic force generates a torque that rotates the dc motor.
What are the classifications of DC machines?
There are 4 main types of DC motors:
- Permanent Magnet DC Motors. The permanent magnet motor uses a permanent magnet to create field flux.
- Series DC Motors. In a series DC motor, the field is wound with a few turns of a large wire carrying the full armature current.
- Shunt DC Motors.
- Compound DC Motors.
What is the general construction of a DC machine?
Construction of DC Machine
The DC machine consists of Yoke, Pole, and Pole shoe, Armature core, Field Winding, Armature Winding, Commutator, Brushes, shaft, and Bearings.
What are the constructional features of a DC machine?
Construction of DC Machine (Generator & Motor)
- Magnetic frame or Yoke.
- Pole Cores and Pole Shoes.
- Pole Coils or Field Coils.
- Armature core.
- Armature Winding.
- Commutator.
- Brushes and Bearings.
What is the maximum efficiency of A DC motor?
The motors are normally designed to have maximum efficiency while working at or near full load. The efficiency of a dc motor at normal operating conditions may be as high as 95%.
Which DC motor has highest efficiency?
Tests carried out on a 44 megawatt 6-pole synchronous ABB motor shortly before delivery showed an efficiency 0.25 percent greater than the 98.8 percent stipulated in the contract, resulting in the world record for electric motor efficiency.
What is the application of DC machine?
Generally, the DC machines are used in supplying excitation of an alternator and it is also used in many applications like welding process, variable-speed motor drives and electrolytic and electroplating process. Small DC machines are used as a control device such as speed sensing, positioning, and tracking.
What are the 3 types of DC motors?
Types of DC Motor
- Series DC Motor.
- Shunt/Parallel DC Motor.
- Compound DC Motors.
- Permanent Magnet DC Motor.
What are the 4 types of DC motor?
The DC motor uses DC current to transform electrical energy into mechanical energy. The main advantage of using this is that we can control the speed, and it occupies less space. There are 4 major types of DC motor.
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They are:
- Series DC Motor.
- Shunt/Parallel DC Motor.
- Compound DC Motors.
- Permanent Magnet DC Motor.
What are the applications of DC machines?
The various applications of DC shunt motor are in Lathe Machines, Centrifugal Pumps, Fans, Blowers, Conveyors, Lifts, Weaving Machine, Spinning machines, etc.
What are the main parts of DC machines in construction?
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 are the application of DC machines?
What is the importance of DC machines?
DC motors offer highly controllable speed. By changing the armature or field voltage it’s possible to achieve wide speed variation and with this level of controllability, DC motors offer the precision required by a wide range of industry applications.
What is the efficiency formula?
Efficiency can be expressed as a ratio by using the following formula: Output ÷ Input. Output, or work output, is the total amount of useful work completed without accounting for any waste and spoilage. You can also express efficiency as a percentage by multiplying the ratio by 100.
What affects the efficiency of a DC motor?
Motor performance depends on three elements such as voltage across terminals, resistance across terminals, and magnetic force.
What is the most efficient motor design?
How can you increase the efficiency of a DC motor?
5 ways to improve the efficiency of your electric motor
- Regular inspection. The most common cause of motor failure is low resistance.
- Protect against electrical overload.
- Keep cool.
- Monitor vibration.
- Protect against contamination.
Which DC motor is best?
Series wound DC motors are best for applications that require high startup torque, without the need for speed regulation. Like a shunt motor, as a load is applied to a DC series motor, the motor speed decreases, which reduces the back EMF and increases the net voltage.
Why starter is used in DC machine?
Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor’s armature winding and restricts the current to an acceptable level.
Why starter is used in DC Machine?
What are applications of dc machine?
What is the application of dc machine?
What is the SI unit of efficiency?
We express efficiency as a percentage. In other words, it has no units (Percent is NOT a unit.). If you look at the efficiency equation at the right, you can see why efficiency has no units. Notice that the SI unit for work out is Joules, which is the same as the SI unit for work in.