Electrical Engineering

If a step-up transformer has 200 turns on the primary coil and 3000 turns on the secondary coil, with a primary coil voltage of 90 volts and current of 30 amps, then the turns ratio is 200:3000, so the secondary voltage is 1350 voltage and the available current is 2 amps. (This ignores losses through the transformer.)

Should work at nearly full power as long as the polarities of the 4 pin plug are in sync and it is a 3 phase 50Hz motor. Do a regular temperature check under full operating conditions for the first hour to ensure speed is enough for cooling.

ic um66 is a melody generator with 3 terminals (1-o/p, 2-vcc,3-grnd)

you know nevish in strawberry hill he likes a girl called amanpreet and he is really ugle and stupid because he just dumps peoplle the answer is sexuallity sexy sex have it in the bed

It depends on whether the field winding of the dc motor is connected in series or in shunt with the armature winding.If it is connected in series,the motor will rotate since the torque,which varies as the product of the armature and field current is always positive.Thus,a positive average torque causes the motor to rotate,however the pulsating nature may cause the commutator segments and brushes to wear out.

Thus only small sized dc motors may be used with ac supply.

wrap a bunch of insolated wire around a ferrous material e.g. a large nail. apply DC voltage to each wire (positive and negative side). when current flows through wire a magnetic field is induced. be very careful when trying this and make sure you don't have shorts and start with a low voltage

CT(Current Transformer) is used to measure current flowing in the circuit. Current can be fully drawn or sensed in series condition. That's why , it is connected in series.

In parallel , the current is divided; and hence the total current cannot be measured)

space charge region in a diode or say a bjt for better understanding is same as the depletion region,

both transition capacitance and depletion capacitance are the same

c= (epsilon*A)/d ;

where ... c is capacitance

A is area

and d is the depletion width

the other type of capacitance is the diffusion capacitance

c= (T*I)/(n*V)

where ... c is the capacitance

T is transition ti

me

I is the drift current

n is emission coefficient ... its value is 1 for germanium

and V is thermal voltage .. 26mv

This arrangement is called SELF-BIAS. Now, if an increase of temperature causes an increase in collector current, the collector voltage (VC) will fall because of the increase of voltage produced across the load resistor (RL). ... One of the most widely used combination-bias systems is the voltage-divider type

The RMS (root mean square) of the peak voltage of a sine wave is about 0.707 times the peak voltage. Recall that the sine wave represents a changing voltage, and it varies from zero to some positive peak, back to zero, and then down to some negative peak to complete the waveform. The root mean square (RMS) is the so-called "DC equivalent voltage" of the sine wave. The voltage of a sine wave varies as described, while the voltage of a DC source can be held at a constant. The "constant voltage" here, the DC equivalent, is the DC voltage that would have to be applied to a purely resistive load (like the heating element in a toaster, iron or a clothes dryer) to get the same effective heating as the AC voltage (the sine wave). Here's the equation: VoltsRMS = VoltsPeak x 0.707 The 0.707 is half the square root of 2. It's actually about 0.70710678 or so.

In general, multiply the (rms) current by the (rms) voltage to get the power.

If the voltage to the appliance is 120 Volts, then the power of 4.2 Amps is 504 Watts. If the voltage is 240 Volts, then 1008 Watts.

Note: To be technically accurate, you must also multiply the cosine of the phase-angle between current and voltage. For any typical appliance, this is 1 and can be ignored.

<<>>

There are zero watts in 4.2 amps. Watts = Amps x Volts. Without a voltage stated the wattage can not be calculated.

the practical applications of maximum power transfer theorem are 1:communication systems

2:control systems

* radio transmitter design

A watt meter that has current through its current coil and voltage across its voltage coil will indicate zero if the power factor between the volts and amps is zero. This condition would be one in which the current will either lead or lag the voltage by 90 degrees and the circuit will have amps, volts, VARS, and VA, but will not have Watts.

Push-To-Make switch is a switch in which pressure is applied to the switch for it to let the electricl current flow through.

The biggest advantage of the Wheatstone bridge is the accuracy of the resistance readings. I had two cables short out underground, by knowing the resistance of the wires per foot I located the fault within 3 feet of where the two wires touched each other.

There are several different types of generators. I'll explain how a "large" 3 phase synchronous generator works - the type that most likely is generating the power you're using at work or home.

The generator is only a small part of a power plant. It is composed of two sets of windings, one on the stator, or stationary part of the generator, and the other mounted on the rotor, or rotating part of the generator. Usually the rotor windings have voltage applied to them by an outside source that is controllable by the power plant operators through what is called the "voltage regulator".

A power source is used to spin the rotor. This can be a steam turbine, a wind turbine, and many others. As the rotor spins, it induces current in the stator windings in proportion to the amount of power applied to the rotor windings by the voltage regulator (VR). This current flows out of the stator windings, which are connected to a load through the transmission system. This current, in turn, induces a reverse force (called "back emf") on the rotor winding. The back emf causes the rotor to slow down. As the rotor slows down, the governor (a system that monitors the generator's speed, and keeps it within a certain range) kicks in to speed the generator back up.

DOL(Direct Online starting)

Star Delta starting

Auto transformer starting

Above methods are for squirrel cage induction motor

Rotor resistance starting is used for wound rotor or slip ring induction motor

If you connect both poles of the same battery together, it will make a short circuit, because the electricity isn't going anywhere, just in one side and back to the other, it will cause whatever you used to connect them VERY hot. Electricity is a type of energy, and MOST energy (i say most because I am not 100% positive they have found an exception in this world) will have some connection to heat. But if you plan on doing it, get a lantern battery, one of the REALLY big batteries, and lay a paperclip on the top of it, or some other conductor on both poles of the battery, and back up. And if you are gonna remove it, wear an oven mitt :D

A transformer's excitation current can be resolved into two components. The first is in phase with the primary voltage, and is responsible for the losses. The second lags the supply voltage by 90 degrees, and is responsible for magnetising the core.

it depend upon the length but for small length we can say 3 amp . . . . . . . . . . . . . . . <<>> 1 sq mm 3-core cable is rated at a maximum of 10 amps but for extended use of up to 6hr per day small cables should be rated at 4 amp per sq. mm, and for continuous use 2 amps per sq. mm..

the loading arrangement used in normal electrical machines is brake drum - spring balance arrangement. This is used to calculate the torque and output power.

the formula for torque is 9.81*(diffference between the spring balance) * radius of brake drum.

thee output power obtained is 2*π*motor speed*torque obtained

A Carey-foster's bridge is a modified version of the meter bridge (wheatstone bridge or potentiometer).

It can be used to find out the average resistance per unit length of the meter bridge wire and hence find out the unknown resistance.

It is more accurate and more sensitive than a meter bridge.

All one can say without more information is that it is less than 1 and greater than zero.