Electrical Engineering

conclusion of dc power supply 9V

U0 stands for the nominal rms-value of the line potential measured with respect to earth.

ESSENTIAL ELEMENTS OF DIESEL POWER PLANT

Fuel Supply System

It consists of storage tank, strainers, fuel transfer pump and all day fuel tank. The fuel oil is supplied at the plant site by rail or road. The oil is stored in the storage tank. From the storage tank, oil is pumped to smaller all day tank at daily or short intervals. From this tank, fuel oil is passed through strainers to remove suspended impurities. The clean oil is injected into the engine by fuel injection pump.

Air Intake System

This system supplies necessary air to the engine for fuel combustion. It consists of pipes for the supply of fresh air to the engine manifold. Filters are provided to remove dust particles from air which may act as abrasive in the engine cylinder.

Exhaust System

This system leads the engine exhaust gas outside the building and discharges it into atmosphere. A silencer is usually incorporated in the system to reduce the noise level.

The exhaust system of a diesel engine performs three functions. First, the exhaust system routes the spent combustion gasses away from the engine, where they are diluted by the atmosphere. This keeps the area around the engine habitable. Second, the exhaust system confines and routes the gases to the turbocharger, if used. Third, the exhaust system allows mufflers to be used to reduce the engine noise.

Cooling System

The heat released by the burning of fuel in the engine cylinder is partially converted into work. The remainder part of the heat passes through the cylinder wall, piston, rings etc. and may cause damage to system. In order to keep the temperature of the engine parts within the safe operating limits, cooling is provided. The cooling system consists of a water source, pump and cooling towers. The pump circulates water through cylinder and head jacket. The water takes away heat form the engine and it becomes hot. The hot water is cooled by cooling towers and re circulated for cooling.

Lubricating System

The system minimises the wear of rubbing surfaces of the engine. It comprises of lubricating oil tank, pump, filter and oil cooler. The lubrication oil is drawn from the lubricating oil tank by the pump and is passed through filter to remove impurities .The clean lubrication oil is delivered to the points which require lubrication. The oil coolers incorporated in the system keep the temperature of the oil low.

Engine Starting System

This is an arrangement to rotate the engine initially, while starting, until firing starts and the unit runs with its own power. Small sets are started manually by handles but for larger units, compressed air is used for starting. In the latter case, air at high pressure is admitted to a few of the cylinders, making them to act as reciprocating air motors to turn over the engine shaft. The fuel is admitted to the remaining cylinders which makes the engine to start under its own power.

When designing a transformer you have to calculate the number of primary windings so that the transformer will operate properly/efficiently. There are a few different variables that have to be taken into account.

Ac:

Ac is the effective cross sectional core area. This number should be supplied by the core manufacturer.

B:

Flux density (B) is expressed in gauss. If the flux density is too high the core will saturate (effectively disappear from the magnetic circuit - very bad). Generally, in car audio amplifier switching power supplies operating at or below 35.000hz, the flux density is kept at or below 2000 gauss. Some cores will operate at higher flux density for frequencies below 35,000hz but 2000 gauss is a good conservative number. For higher frequencies, you have to design for lower flux density to prevent excess core heating. For a more precise value for a given core material, refer to the core manufacturer.

Primary Voltage:

The primary voltage for a push-pull system is double the primary input voltage. For car amplifier switching power supplies, the input voltage is 12VDC. This means that the total primary voltage is 24 volts. If we use 13.5 volts as the input voltage, the primary voltage would be 27 volts.

Operating Frequency:

The operating (oscillation) frequency is simply the frequency at which the primary is driven. Generally between 25,000hz and 50,000hz in car audio amplifiers.

Primary Turns:

The number of primary turns returned by the calculator is the total number of turns on the primary side of the transformer. Of course, with a push pull system, the number of turns on each half of the primary must be equal. If the output says that you need 13 turns, you'd round up to 14 turns and each half of the primary would have 7 turns. From the previous diagram, you'd have 7 orange turns and 7 green turns on the core.

Skin Effect:

When wire (specifically, solid copper conductors as are used for transformers) is used to carry DC current, the entire cross sectional area of copper carries the current equally. When wire is used for AC current, the current is carried differently. At low frequencies, the current flow is not significantly affected by the skin effect. As you get into the higher frequencies (as those used to drive a transformer in a switch mode power supply), the current flow is carried disproportionately by the outer area of the copper wire (especially for large single solid conductors). This is called the skin effect. If, for example, you are using 14g wire at 100khz, the wire will not be able to carry the same amount of current as it could if it were passing DC. If your calculations told you that you needed to have ~4120 circular mils, you'd have a few choices. You could use 1 strand of 14g wire, 3 strands of 17g or 6 strands of 20g. All would have the same current carrying capacity if you were using it in a DC circuit but... If you were using it for AC, the 14g would only be suitable for frequencies below ~6000hz. Above that frequency, the voltage losses and power dissipation may be unacceptable (it would still work above 6000hz but not efficiently). The maximum frequency that you'd want to use with the 17g would be about 11,000hz. For 22,000hz the 6 strands of 20g would be a good choice.

In series resonance, the inductance and the capacitance are connected in series, but in parallel resonance they are connected in parallel. In series resonance, at an input signal with a frequency equal to resonance frequency, the total impedance of both inductive and capacitive elements together is zero (or they appear as short circuits) unlike the parallel resonance case in which it is infinite and they appear as an open circuit.

Because they can be used to obtain or get an output (on a series connected resistance with them) for a specific frequency of the input signal. This is the ideal case, but in fact, the resonance circuit passes a band (not a single frequency) of input signals' frequencies to take them at the output terminal. They are also termed as ( filters or filtering circuits ). They are called selective as they function as if they select signals of specific frequencies to be passed to the output.

Segmental level

there are some distortion in transmission line :

copper loss,dielectric loss,skin effect

The metal frame of the toaster is connected to earth (ground) so that should the line (live) conductor make accidental contact with that frame, the resulting earth-fault current will be large enough to operate the protective fuse or circuit breaker, which will disconnect the toaster from its supply. The earth wire is simply an alternative route back to the supply transformer for current.

if channel width decreases , the drain current(Id) will also decrease .

but , Id will decrease up to a certain limit , when the jfet is in pinch off condition i.e. channel width is tends to zero (Vgs is very high) the Id will be constant then.

A tap changer is used to vary the turns ration between the windings of a transformer to make minor changes to the secondary voltage. An on-load tap changer enables the turns ratio to be altered without disconnecting the transformer. An off-load tap changer requires the transformer to be temporarily diconnected. On-load tap changers are installed on the high-voltage side of the transformer, where the current is lower.

stop cheating ryan zagrovic from brotton, redcar and cleveland

its nothing but alternate occurence of pole/zero and zero/pole. ex: f(s)=s*(s+2)/(s+1). here we can easily sense that there is a occurence of zero(s=0),pole(s=-1),zero(s=-2).

It can be answered in two ways :

1. ratio of output & input voltages [Vout / Vin] i.e Drain voltage(Vds)/Source voltage(Vs).

2. multiplication of trans-conductance & drain resistance .

The series capacitors can be the cause of overcompensating on the power line and thus cause the following problems:-

a) Over voltages on the line when connected loads are smaller than the rated loads and this can damage the transformers and capacitors

b) Ferro-resonace phenomenon can cause very high volatges again can be damaging

c) The fault level of the poweer system will increase and if not considered in the design, the fault current could exceed thedesign limits.

Certain "Lap" wound armatures.

Electromagnetic attraction relays have a fixed contact and a moving contact, attached normally to either a hinged plate, or the moving piston of a solenoid. The contacts are brought together by the magnetic attraction of an energized coil attached to one of the contact supports, or in the case of the solenoid, the coil which surrounds the moving piston. These relays can operate on either ac or dc inputs, and have virtually no time delay. This makes them ideal for instantaneous operations.

Electromagnetic induction relays operate on the principle of the induction motor - that is, magnetic flux applied to a rotor will develop torque in that rotor, and cause it to rotate. However, instead of spinning like a motor, the rotor in this type of relay has a mechanical stop or reset point, and a contact fixed to it that will eventually touch the stationary contact, when the input quantity meets or exceeds the predetermined setpoint. Relays of this type only operate with ac quantities, and, in many or most cases, can be adjusted to provide a time delay (which in reality simply moves the reset point farther away from the contact point, so that the rotor must rotate farther to pick up the contacts).

There aren't any similarities. They are different types of components.

40 watt light bulb. This is obvious. Go do an experiment. -_-