- 1 What is the purpose of laminating the armature?
- 2 Why do we use laminated sheets to build the stator and rotor cores of an induction motor?
- 3 What is the lamination used for the stator?
- 4 Why do we laminate the armature of a DC machine?
- 5 What is the function of commutator?
- 6 What is back emf in dc motor?
- 7 Which motor is used for fan application?
- 8 What are the main parts of 3 phase induction motor?
- 9 Why do laminations reduce eddy currents?
- 10 What is formula for stator turns per phase?
- 11 What is lamination stamping?
- 12 What is a lamination stack?
- 13 Why Copper brushes are not used in DC machines?
- 14 Why Interpoles are used in DC machine?
- 15 What is the speed of dc motor?
What is the purpose of laminating the armature?
Instead of having just a solid and large piece of material, these thin pieces are capable of generating a higher resistance. As a result, fewer eddy currents take place, which ensures a lower amount of eddy current loss taking place. These individual pieces of iron are called laminations, which an armature comes with.
Why do we use laminated sheets to build the stator and rotor cores of an induction motor?
During the process of induction heating, the bearing heats up quite quickly while the cross bar stays relatively cool. Simply stated a stator core is laminated and insulated in order to reduce induced circulating currents and associated heat down to a manageable level.
What is the lamination used for the stator?
2. What is the lamination used for the stator? Explanation: The stator is made up of a block of laminations. The block of laminations are made up of cast iron or die cast aluminium alloy frame.
Why do we laminate the armature of a DC machine?
To minimize the eddy current loss we increases the resistance in the path of eddy current by laminating it. Eddy current losses are directly proportional to area of armature or more precisely the path of motion. That is why armature of DC machines (either motor or generator) is laminated.
What is the function of commutator?
Commutator and Brushes The commutator on the DC generator converts the AC into pulsating DC. The commutator assures that the current from the generator always flows in one direction. The brushes ride on the commutator and make good electrical connections between the generator and the load.
What is back emf in dc motor?
Back emf is the generator output of a motor, and so it is proportional to the motor’s angular velocity ω. It is zero when the motor is first turned on, meaning that the coil receives the full driving voltage and the motor draws maximum current when it is on but not turning.
Which motor is used for fan application?
In conventional ceiling fans, single phase induction motor is used. These motors consume minimum power and hence, are also known as fractional kilowatt motors. A single phase induction motor requires only one power phase for operating. It converts the electrical energy from the power input into mechanical energy.
What are the main parts of 3 phase induction motor?
The stator of the three-phase induction motor consists of three main parts:
- Stator frame,
- Stator core,
- Stator winding or field winding.
Why do laminations reduce eddy currents?
By laminating the core, the area of each section and hence the induced EMF is reduced. Eddy currents can also be reduced by using a magnetic material such as silicon steel, with a higher resistivity.
What is formula for stator turns per phase?
Turns per phase of Induction motor Number conductors /phase, Zph = 2 x Tph, and hence Total number of stator conductors Z = 6 Tph and conductors /slot Zs = Z/Ss or 6 Tph/Ss, where Zs is an integer for single layer winding and even number for double layer winding.
What is lamination stamping?
The individual pieces of iron are called laminations. Metal stamping is one procedure used to create motor laminations for different applications. Metal stamping presents customers with a wide range of customization capabilities, as the dies and materials used for it can be designed to customer specifications.
What is a lamination stack?
Lamination stacks are packages of individual sheets separated by electrically insulating layers to suppress eddy current losses under dynamic magnetic loading. These parts are mainly used as stators and rotors in electric motors and generators but also as laminated cores.
Why Copper brushes are not used in DC machines?
The brush in a DC machine is a component that collects the current from the moving parts and feeds it to the stationary circuit. Brushes are usually made from carbon or graphite, but copper brushes are preferred in low voltage high current requirements. This loss is mostly enclosed in armature copper loss.
Why Interpoles are used in DC machine?
Inter poles in dc machines help to reduce armature reaction effects in the inter polar regions and their windings are connected in series with the armature so that its effect can vary with the armature current.
What is the speed of dc motor?
DC controls adjust speed by varying the voltage sent to the motor (this differs from AC motor controls which adjust the line frequency to the motor). Typical no load or synchronous speeds for an AC fractional horsepower motor are 1800 or 3600 rpm, and 1000-5000 rpm for DC fractional hp motors.