More about the Electric Motor
The principle used in motors is another aspect of the principle of induction. The law states if a charge is moving in a magnetic field, a force acts on the charge in a direction perpendicular to both the velocity of the charge and the magnetic field. The same principle applies for a flow of charge, is a current and the conductor carrying the current. The direction of this force is given by Fleming’s right hand rule. The simple result of this phenomenon is that if a current flows in a conductor in a magnetic field the conductor moves. All the induction motors are working on this principle.
As like the generator, the motor also has a rotor and a stator where a shaft attached to the rotor delivers the mechanical energy. The number of turnings of the coils and the strength of the magnetic field affects the system in the same way.
| What is the difference between Electric Motor and Electric Generator? • Generator converts mechanical energy to electrical energy, while motor converts mechanical energy to electrical energy. • In a generator, shaft attached to the rotor is driven by a mechanical force and electrical current is produced in the armature windings, while the shaft of a motor is driven by the magnetic forces developed between the armature and field; current has to be supplied to the armature winding. • Motors (generally a moving charge in a magnetic field) obey the Fleming`s left hand rule, while the generator obeys Fleming’s left hand rule. |
Тема № 4 Electrical Wiring Installation .
Проведение электропроводки.
1. Выполните письменный перевод профессионально-ориентированного текста
2. Составьте глоссарий профессиональных терминов.
Phase Electrical Wiring Installation at Home
3-Phase Consumer Unit Installation from Utility Pole to 3-Phase Energy Meter & 3-Phase Distribution board and How to Connect Single Phase & Three Phase Loads in a Three Phase Wiring Distribution System
Requirements
Three Phase Energy meter 1 No
Three Pole MCCB, 63A, 1 No
Double Pole, 63A, 30mA Trip Current RCD, 3 Nos
Double Pole MCBs, 63A, 3 Nos
Single Pole, 20A, MCB, 6 Nos
Single Pole, 16A, MCB, 3 Nos
Single Pole, 10A, MCB, 6 Nos
Distribution board cases, 3 Nos
Bus bar Link for Neutral Cable Connections
Cupper strips for MCB Common connection, 3 Nos
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Briefing
Generally, Electric company installs Single phase energy meter for less than 7.5kW (10HP) load in domestic areas (consumer unit for home). If the limit is exceeded, then it’s recommended that install a 3-phaseenergy meter for Consumer units, when load is exceeds from 7.5 kW, then 3-phase electrical wiring is recommended in domestic areas (Homes)
Theory
We assume that we will only connect single phase load (Light points, fans, TV, AC etc.) in this three phase electrical wiring installation. In other words, we will not power up 3 phase motors because in our homes, we haven’t that kind of (three phase) loads. If three phase load exists in your home, then you can so. As we can see that the total load is exceeded the limit of single phase electrical wiring installation, that’s why we have to wire our distribution in three phase system.
Practical Procedure of Three Phase wiring of distribution board & installation
As we have learned the basic electrical wiring of bulb, fans etc (i.e. Sub-circuits and final sub circuits)
· First of all, connect the three-phase energy meter as shown in fig. ( if you don’t sure that how to wire a 3-phase energy meter, then check this simple method. Howtowire a Three-PhaseEnergyMeter)
· Connect the MCCB (Moulded Case circuit Breaker) as main switch to the incoming three phases (R, Y, B) from 3-phase energy meter
· Now connect the outgoing phases (R, Y, B) from MCCB (Moulded Case circuit Breaker) to the DP (Double Pole MCB , RCD, SP (Single Pole MCBs and load) as shown in fig)
· Also connect the Neutral wires to RCDs and then to neutral links and then to specific loads (as shown in fig).
How to Connect Single Phase & Three Phase Loads in a Three Phase Wiring Distribution System
In the above 3-phase wiring system, load can be connected by this way
General Precaution
· Disconnect the power source before servicing, repairing or installing electrical equipments and installation.
· Also use the proper cable in size with this simple calculation method ( How to determine the suitable size of cable for Electrical Wiring Installation)
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· Never try to work on electricity without proper guidance and care
· Work with electricity only in presence of those persons who has good knowledge and practical work to deal with electricity
· Read all instruction and cautions and follow them strictly.
· The author will not be liable for any losses, injuries, or damages from the display or use of this information or try any circuit in wrong format so please! Be careful because it’s all about electricity and electricity is too dangerous
Тема № 5 PowerStations .
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