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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
What happened if no neutral you can use a ground?
system will b damaged or destroyed in case of failures.............if we provide neutral d short ckt current passed through earth directly ,with out disturbing the system
How winding is connected to stator in ac motor?
in 3 phase motor u1,v1,w1 give to the short terminal and remaining v2,u2,w2 give t0 the in coming power supply of 440v
What does a capacitor store if the sum of charges of both capacitors is zero?
it may consist much of negative and positive charge
AnswerA capacitor stores energy within an electric field set up between its plates. It does not 'store' charage, as the net charge is the same both before and after the capacitor has been 'charged' (unfortunate use of the word!). What it does is to enable charge to be separated, with one plate then becoming negative with respect to the other, resulting in an electric field between the two plates.
When we describe the 'amount of charge' on a capacitor, by convention, we mean the amount of negative charge stored on its negative plate, and not the sum of this and the amount of positive charge on its positive plate!
Phase diagram are also known as thermal equilibrium diagram or a consistutional diagram
1. Different uses of phase diagram are
2. prediction of phase
3. amount of phase
4.composition of phase
Why insulation is needed on current carrying conductors?
To prevent the wire from getting short circuited to ground or even to other wires.
What is a voltage transformer and mention its function?
A voltage transformer (known as a 'potential transformer' in North America) is classed as an instrument transformer. It is used to reduce the voltage across a high-voltage load to a value that can be read (usually remotely) by an ordinary a.c. voltmeter, while electrically isolating that voltmeter from the high-voltage system for the purpose of safety. It can also be used to supply an input to a protection relay.
What is economic dispatch control?
It is the operation of generation facilities to produce energy at the lowest cost to reliably supply power to customers, recognizing operational restrictions of generation and transmission facilities.
How many microfarad of starting capacitor is best for 15hp 3phase motor?
Starting capacitors are only required for single-phase induction motors. They are not necessary for three-phase motors.
How do you reduce the Power dissipation?
Answer for mechanical systems:
Use oil or grease to reduce friction!
Answer for electrical systems:
Making the voltage as high as possible is a good way to reduce power loss.
Explanation
The voltage drop along a conductor is proportional to the resistance and to the current carried. (V=IxR) So, for a given quantity of Power (W=VxI), if the voltage is made as high as possible there will be less current flowing and therefore less power loss.
What are the industrial applications of brushless servo motors?
Industrial servo motors control position. Higher functioning servo motors may also detect speed in addition to position. Controlling speed provides benefits rather than always functioning at full speed.
Can you run a 460v 60hz motor to a 480v supply?
The the supply stays within +/- 5% of what the motor is rated for, you can do this.
What is difference between breakdown voltage and dielectric strength of transformer?
The dielectric strenght of a transformer represents the maximum voltage permissible to apply across the transformer insulation i.e. between the transformer winding to another part of the transformer, normally the chassis or another winding and without break-down of the insulation ocurring (e.g. arcing).
The breakdown voltage of a transformer represents a voltage that exceeds its dielectric strenght and that causes breakdown e.g. arcing across the insulation.
What does a buck boost transformer do?
A buck boost transformer is a type of transformer that is used to make adjustments to the voltage applied to alternating current equipment. These transformers are typically used in back up supplies or in tanning beds.
What is a shunt resistor used for?
A shunt resistor is used to carry a majority of the electrical current away from the outlet. This causes the risks of electric shock to be down significantly, but still not completely gone.
How do you find the resistance of a series circuit with n identical resistors?
The total resistance of resistors in series is simply the sum of the resistance values of those resistors. If the resistors are identical, then you can multiply the resistance of one of them by the number of resistors in the circuit.
What equivalent size electric motor will replace a 8 HP gasoline engine?
If the gasoline engine must supply energy at the rate of 8 horsepower to its load, then so too must the electric motor. Expressed in watts, 8 horsepower is equivalent to 6 kilowatts. So the output power of the motor must be 6 kilowatts.
How many units of electricity does 0.75HP motor consumes per hour?
A unit, short for 'Board of Trade unit', is used to measure energy and is exactly equivalent to a kilowatt hour.
When a motor is described as being rated at, say, 0.75 horsepower, what is being described is its output power or the rate at which it is supplying energy to its mechanical load. So, it's necessary to determine what the input power (which is greater than its output power) is and, to do this, you need to know its efficiency.
If we assume that the efficiency of the motor is, say, 85% at its rated output, then the input power will be (0.75 x 746) / 0.85 = 658 watts. The amount of energy supplied to the motor, therefore, will be (658/1000) x 1 = 0.658 kilowatt hours.
Where can one buy Onan Generator?
One can purchase an Onan Generator online from 'Electric Generators Direct'. Some models can also be purchased on Amazon and there are many listed on eBay both used and new.
What is the importance of Megger test?
Megger tests are important because the test makes sure that your electrical insulation is safe and operating as intended. Megger tests are performed using a Meg-ohmmeter.
How should a ammeter and voltmeter be connected in circuit?
Ammeter is coneccted in series with circuit but Voltmeter is connected in parallel.
