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A (50/60 Hz) Transformer. Which one will give more Output? (When operates on 50 or 60 Hz frequency) A Transformer is designed to be operated on both 50 & 60 Hz frequency.  For the Same rating, which one will give more out put; when,   Operates on 50 Hz    Operates on 60 Hz Obviously!  It will give more out put when we operate a transformer (of same rating) on 50 Hz instead of 60 Hz. Because in previous posts, we proved that, in inductive circuit,  when frequency increases, the circuit power factor decreases . Consequently, the transformer out put decreases. Let’s consider the following example. Suppose, When Transformer operates on  50 Hz  Frequency Transformer = 100kVA, R=700 Ω , L=1.2 H, f= 50 Hz. X L  = 2πfL = 2 x 3.1415 x 50 x 1.2 = 377 Ω Impedance Z = √ (R 2 +X L 2 ) = √ (700 2 + 377 2 ) = 795 Ω Power factor Cos θ = R/Z = 700/795 = 0.88 Transformer Output (Real Power) kVA x Cos θ 100kVA...

How to find The value of Burnt Resistor ( By three handy Methods ) Find The value of Burnt Resistor by Three Simple Methods  We can find the Values of  burnt resistors  by these three handy methods below. Method 1 Scarp the outer coating. Clean the Burnt Section of the resistor. Measure resistance from one end of the resistor to the damaged section. Again measure the resistance from damaged section to the other end of the resistor. Add these two value f resistances. This is the approximate value of Burnt resistor.  Just add a small value of resistance for damaged section i.e., suppose the value of burnt resistor was 1k Ω, but you got 970 Ω. So just add 30 Ω, and you will have 1k Ω. Also Read:  How to check a Capacitor by 4 Simple Methods Method 2 This method can also be used for finding the value of  burnt resistor(s) (also, may be applied on connected resistors in the circuit) in case if you don’t know about Resis...

Why Battery rated in Ah (Ampere hour) and not in VA. Why Battery rating in Ah (Ampere hour) and not in VA. Battery stores charge in the form of chemical energy and then converts it into electrical energy to utilize for a specific time. The amount of available charge is the capacity of a cell or battery which may be expressed in Ah (Ampere-hour). Moreover, in a charged battery, the numbers of molecules are limited to create a flow of electron in electric circuits, so, there must be a limited number of electrons in a cell/battery which they motivate through a circuit to fully discharge. Now we have the option to rate the battery capacity in Number of flowing electrons for a specific time, but, it would be a headache, because there are a vast number of electrons in it.  So we have another option  (1C (Coulomb) = 6.25 x 10 18  electrons , or 6,250,000,000,000,000,000 electrons. In addition,  1A (Ampere) = 1 coulomb of electrons per secon...

Why Motor rated in kW instead of kVA Why Motor rated in kW/Horsepower instead of kVA? We know that  Transformer rating may be expressed in kVA  as well as Generator and  Alternator rated in kVA  Designer doesn’t know the actual consumer power factor while manufacturing transformers and generators i.e. the P.F (Power factor) of Transformer and Generator/Alternator depends on the nature of connected load such as resistive load, capacitive load, and inductive load as Motors, etc. But  Motor has fixed Power factor, i.e.  motor has defined power factor and the rating has been mentioned in KW on Motor nameplate data table . That’s why we are rated Motor in kW or HP (kilowatts/ Horsepower) instead of kVA. In addition, Motor is a device which converts Electrical power into Mechanical power. In this case, the load is not electrical, but mechanical (Motor’s Output) and we take into the account only active power which has to be...

What is slip in an induction motor? Slip can be defined as the difference between the flux speed (Ns) and the rotor speed (N). Speed of the rotor of an induction motor is always less than its synchronous speed. It is usually expressed as a percentage of synchronous speed (Ns) and represented by the symbol ‘S’.

Why back emf used for a dc motor? highlight its significance. The induced emf developed when the rotating conductors of the armature between the poles of magnet, in a DC motor, cut the magnetic flux, opposes the current flowing through the conductor, when the armature rotates, is called back emf. Its value depends upon the speed of rotation of the armature conductors. In starting, the value of back emf is zero.

What are the various kind of cables used for transmission? Cables, which are used for transmitting power, can be categorized in three forms: • Low-tension cables, which can transmit voltage upto 1000 volts. • High-tension cables can transmit voltage upto 23000 volts. • Super tension cables can transmit voltage 66 kV to 132 kV.

How can you relate power engineering with electrical engineering? Power engineering is a sub division of electrical engineering. It deals with generation, transmission and distribution of energy in electrical form. Design of all power equipments also comes under power engineering. Power engineers may work on the design and maintenance of the power grid i.e. called on grid systems and they might work on off grid systems that are not connected to the system.