Electrical Engineering

Inverse definite minimum time lag relay

VAr is reactive power, caused by either inductive or capacitive loads. The ideal power factor to have is 1, anything less than that is a loss on the network. The effect of VArs on the circuit though depends. If you have a load that is mainly inductive, then adding more inductive reactance will lower the power factor. However, if you introduce capacitive reactance this will increase the power factor, and the opposite is true if its a mainly capacitive circuit. So VArs will either increase or decrease the power factor depending on the load of the circuit. The ideal situation is to balance inductive reactance with capacitive reactance so they in effect cancel each other out and power factor is 1.

• Series clipper diodes are in series connection with the load while Parallel clippers are in parallel connection with the load.

Two names for practically the same condition. Peak inverse is name whereby the maximum voltage can be sustained. Breakdown is actually the point where a reverse voltage is reached and reverse breakdown has occurred

If we use the simple application of Ohm's law where voltage (E) equals current (I) times resistance (R), or E = I x R, all we need to do is plug in values. If E = I x R and I = 8 amps and R = 15 ohms, E = 8 x 15 = 120 volts.

Polarization Index is an indicator which gives an idea of the cleanliness of the windings. It is a ratio of the Insulation Resistance Measured for 10 minutes to the insulation resistance value measured after 1 minute. Since it is a ratio; it does not have any units.

Polarization Ratio = Insulation Resistance after 10 minutes/ Insulation Resistance after 1 minute

The Polarization Index should be above 2.0 to be permissible. Machines having PI below 2.0 cannot be operated. The Polarization Index does not have any significant relation with temperature upto 50 deg. C. However, the Polarization Index test should not be conducted at a temperature beyond 50 deg. C

A mains tester works because the potential difference between the live and Earth makes a very small (imperceptible) current flow through the tester and our body to Earth. This current is just enough to light the lamp / Neon. When you stick it in the Neutral socket, the potential difference (just a volt or two, usually) is not enough to give sufficient current to light the neon.When the tester light glows, it mean electrons flow like,from live terminal > tester > body > floor & walls of building > inside the earth>goes back to the generator, via earth or neutral conductor (Please note that somewhere, Neutral and Earth are connected together so we have, in effect, a huge loop of circuit.)

Above description is for AC supply only ( path complete thorough earth or nutral to generator neutral), however please note the fhilosophy is not applicable for DC supply where - V is in floting condition (not grounded or earthed) so due to un completation of that circuit tester light will not glow.

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Transducer is a device which convert physical signal into electrical signal ( current/voltage/resistance). for linear measurement we can use LVDT (Linear Variable Displacement Transducer/ Linear Variable Differential Transformer). and for rotary measurement we can use RVDT (Rotary Variable Differential Transformer)

For a small generator like the 125 Watt Alternator/Generator in your car, 12 Volts at a couple Amps.

For a large 1,200,000,000 Power Plant Generator typical excitation is 600V at 8000A.

A timer in star delta starter for a three phase motor is an electronic device designed to do the change over or transition from star connection - using which the motor suns on a reduced voltage and current and produces less torque - to the delta connection necessary for running the motor at its full power, using high voltage and current to produce a high torque.

The timing interval that is set is dependent how long the motor needs to start up from standstill to normal speed. Some motors require 15 seconds for the initial startup in star connection and after that given value of time the timer signals to the star contactor to go to the open position and the main delta contactor to go to the closed position, thus forming the delta circuit.

forward breakover voltage is slightly smaller than reverse breakdown voltage

yes

single phase power measure by three ammeter method

Usual symbol for diode is with a triangle - looking as an arrow hinged with a vertical line. Arrow head stands for anode for diode and line stands for its cathode.

To give the symbol for zener diode we simply replace the vertical line by letter Z which also symbolizes the first designer 'Zener'

traffic signal,blind person,

2ft 6 inches

to produced reducing equivalents NADPH + H+ for Lipid synthesis

To generate pentose sugars for nucleotide synthesis

Current = charge / time....so 0.67 c / 0.30 s = 2.23 A

100

The power dissipated by a circuit with a voltage of 12V and a current of 3A is 36W. Watts is Volts times Amps.

It's a description of the some of the electrical properties of the transformer. This is a Delta connected highside (the D), wye connected lowside (Y) that is grounded (N) and there is a 330 degree phase shift between the highside and the lowside (the low voltage is leading the high voltage by 30 degrees).

first step, use worm reduction gearbox