Electrical Engineering

Squirrel cage motor

The longer the conductor the greater the end to end resistance.

A diode is a solid state passive device that will only allow current to flow in one and only one direction (Anode->Cathode). A Thyristor behaves exactly like a Diode except that in order for current to flow it must "see" current at its gate, if it does not see current (ie logic 0 or ground) then current is not allowed to flow from its anode to cathode.

Note: The Thyristor gate requires little current to trigger its gate, meaning a small amount of current can be used to switch on/off a load require much more current.

Another Note: Since the Thyristor has a gate which controls its output it is not a passive device like the diode

You can not change it. 440 volt is by design. However you run it with 220 single phase supply, but it would run far lower power.

An inductive accelerometer operates based on the principles of electromagnetic induction. It typically consists of a mass suspended by a spring, with coils of wire around it. When the accelerometer experiences acceleration, the mass moves, changing the relative position of the coils and the magnetic field. This movement induces a voltage in the coils, which is proportional to the acceleration experienced, allowing for the measurement of dynamic forces.

Step 1: calculating knee point voltage Vkp

Vkp = {2 x Ift (Rct+Rw)}/ k

Vkp = required CT knee point voltage

Ift = max transformer through fault in ampere

Rct = CT secondary winding resistance in ohms

Rw = loop impedance of pilot wire between CT and the

K = CT transformation ratio

Step 2: calculate Transformer through fault Ift

Ift = (KVA x 1000)/(1.732 x V x Impedance)

KVA = transformer rating in kVA

V = transformer secondary voltage

Impedance = transformer impedance

Step 3: How to obtain Rct

To measure when CT is produce

Step 4: How to obtain Rw

This is the resistance of the pilot wire used to connect the 5th class X CT at the transformer star point to the relay

in the LV switchboard. Please obtain this data from the Electrical contractor or consultant. We provide a table to

serve as a general guide on cable resistance.

Example:

Transformer Capacity : 2500kVA

Transformer impedance : 6%

Voltage system : 22kV / 415V 3phase 4 wire

Current transformer ratio : 4000/5A

Current transformer type : Class X PR10

Current transformer Vkp : 185V

Current transformer Rct : 1.02½ (measured)

Pilot wire resistance Rw : 25 meters using

6.0mm sq cable

= 2 x 25 x 0.0032

= 0.16½

Ift = (kVA x 1000) / (1.732 x V x impedance)

= (2500 x 1000) / (1.732 x 415 x 0.06)

= 57,968 round up 58,000A

Vkp = {2 x Ift (Rct+Rw) } / k

= {2 x 58000 (1.02+0.16) } / 800

= 171.1½

In physics, power is the rate at which energy is transferred, used, or transformed. The unit of power is the joule per second (J/s), known as the watt (in honor of James Watt, the eighteenth-century developer of the steam engine). For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts-the more wattage, the more power, or equivalently the more electrical energy is used per unit time.

Yes but very slightly,because temperature coefficient of bulb element is very low.

Resistance of stator winding is the resistance of the copper conductors being used for building the windings of three separate phases, i.e. R-Y-B. These windings are marked like U1-U2, V1-V2 & W1-W2 at the motor terminals (6 nos.) for the three phases, i.e. R-Y-B respectively. We have simply to measure the resistance of each winding by using a multimeter by connecting the terminals (2 no.) to U1 & U2 and so on.

The resistance should be in ohms not milliamps [amps is form of measuring current not resistance] milliamps to microamps in case of large motors, it may be in amps in case of small sized motors. But resistance of each winding should be nearly same to each other. This shows the electrical balance among windings & also proves the healthiness of the winding.

a switchgear is a term used with the electric power distribution system, and is basically a large switch or set of switches used in switching very high voltages at very high currents and can occasionally have arc overs, though they are ushually supressed by a number of safety measures. medium voltage probably being under 100KV but more than 5KV, but that's just a guess as to voltage ratings...

The ratio of RB1 to RBBO is the intrinsic standoff ratio. It is the standoff voltage ratio to the power supply voltage.

Unipolar full step Stepper motor: _ _

INPUT SEQUENCE: X Y X Y

1 1 0 0

0 1 1 0

0 0 1 1

1 0 0 1

8255 CONTROL WORD: 1 0 0 0 0 0 0 0 =80H

PROGRAM:

MVI A, 80

OUT port B

START MVI A, FC

OUT port A

CALL DELAY

MVI A, F6

OUT port A

CALL DELAY

MVI A, F3

OUT port A

CALL DELAY

MVI A, F9

OUT port A

JMP START

DELAY LXI D, 0003

CALL DELAY

RET

no

Yes, it is possible and was in common use during the early 20th century. In a two phase system the phases are 90 degrees apart. It is important to note the difference between the 3 wire single phase common in North American homes and true two phase power. As far as I know, there are few, if any two phase systems still in use.

See

http://en.wikipedia.org/wiki/Two-phase_electric_power

for more information.

The utility company can provide a 480 volt, single phase service from a single phase transformer, usually with a three wire service. 480 volts is measured between the two line conductors, and 240 volts is measured between either line conductor and the common neutral conductor. The voltage of the line conductors are at 180 degrees with respect to the neutral conductor.

A 400 Hz transformer is designed to operate optimally at that frequency and may not function correctly at 50 Hz. When supplied with 50 Hz, the transformer could experience issues such as overheating, increased magnetic losses, and reduced efficiency due to the lower frequency not matching its design specifications. Additionally, the core might saturate, leading to potential damage. Therefore, while it may physically operate, it is not advisable to use a 400 Hz transformer at 50 Hz.

Conductance is the reciprocal of resistance, and is measured in siemens (S).

So a 5.1 ohm resistor has 1/5.1 conductance,

which is approximately 0.196 078 431 372 549 019 607 843 137 254 9 S.

Well the big identifier of a split phase induction motor is the main and aux. winding. The rotor, stator, case, etc. These two windings is what sets it apart from other motors. These windings are phase shifted to produce a rotating magnetic field for starting to allow the motor to have better starting torque.

On a step down transformer XO symbol denotes the secondary split phase grounding point. This is also where the neutral of the three wire secondary is connected. The transformer connection is known as a single phase - three wire - with one secondary winding.

Your question is confusing. Are you asking how to reverse the direction of a three-phase motor? If so, then the answer is that you simply interchange any two of the line conductors. This will cause the naturally-rotating magnetic field in the motor's air gap to reverse direction, causing the rotor to reverse direction.

kote pak hang

Using a higher voltage reduces power losses during transmission.

E=sin(Theta);

You need to normalize the equation for the electric field of the half-wavelegnth dipole. recall E=sqrt(ExE*) where E* is the conjugate of the E field.

This is why you only get an eight shaped figure (or infinity symbol) when you plot it. you will get this figure if the dipole is placed in the axis of interest. e.g. if it is in the placed in the x axis, you will get an eighth in the x-y,x-z, but you will get a donut shape in the y-z (no angle to measure)

hope this helps a bit.