Electrical Engineering

the magnitude is decided by the amount of flux, number of conductors, speed of the motor and the type of the winding used.

the polarity is decided by the direction of rotation of the motor and the direction of armature current flowing in the motor.

Work it out for yourself. The equation is: R = resistivity x (length/area). Incidentally, 1.55 m2 is an enormous area, if you are describing a conductor!!!! And 2.8 doesn't appear to represent a practical value of resistivity.

That is how inductance works. The rise is needed to charge the primary. When the field collapses, that is when the current is induced in the secondary winding(s).

In this context, 'wind', in 'windage', is pronounced as 'wind' -as in 'breeze' or 'gale'. 'Windage means air-resistance, and this only applies to rotating machines, such as generators and motors, whose rotors have to overcome air-resistance (windage) as they rotate. As transformers have no moving parts, they are NOT subject to windage loss!

No,look at the connection diagram for Universal motor. The Field and the armature windings are connected in series. But, in induction motor, the rotor end terminals are sorted by a kind of rings.That is rotor is apart from the supply.

'Switchgear' is a generic term for all switching devices, such as circuit breakers, isolators, air-break links, etc. A reactor is simply a coil so, no, it is not classified as being switchgear.

The vector-relationship between apparent power, true power, and reactive power is represented by a right-angled triangle, whose hypotenuse represents apparent power and whose adjacent represents true power. Since power factor is defined as 'the ratio of true power to apparent power', you will find that this ratio corresponds to the cosine of the angle between them.

case study

induction

insulation resistance = (2 * operating voltage +1000V)

at operating temperature

if you define what you mean by minimum insulation resistance maybe i could help

132,000V on the towers is usually happy with 6' of air

some insulation is far better than air

dry air 500v/mill

thermoplastics 6000v/mill

your power drill has 1/8" - 1/4" of plastic on the cord

and perhaps .001" on the wire in the coils

the cord gets rougher handling

anything practical insulation resistance (2 * operating voltage +1000V)

witch means a 1500Vdc megger is ok for 120V appliances

should be safe to handle if its more than 10megohms

the 1500V will bridge any pinholes or airgaps

NEVER use a vom the 9v battery wont find a pinhole or an air gap

ceramic on heaters and toasters has a way of letting metals diffuse in it lowering the resistance over time also it usually lowers with temperature

so the resistance reading will be a lot lower while its hot

They can be many different colors, shapes and sizes. To identify whether a capacitor is directional or not, you must look at the markings on it - if it is directional, it will have a little +, and possibly a - to denote directionality (some only have the + I believe due to size).

In general, electrolytic capacitors are normally directionalized. These are the capacitors that resemble batteries in shape, and usually have an 'X' on the bottom (this creates a weak point in the casing; if the capacitor overheats for whatever reason - overvoltaging, or revers polarizing- the 'X' will fail first).

Best guess?

A shading ring aborbs energy from a changing magnetic field, so I'm guessing it will slow the opening and/or closing time.

Try a web search:

electrical contactor shading ring

I believe intrinsic impedance is more tied to the medium, thus is defined in terms of magnetic and electric permeability and electrical conductivity, while characteristic impedance is a "wider" look at the impedance.

For example, you can calculate the intrinsic impedance of a 18 awg copper wire, or air, or a vacuum. If you wanted to use coax cable with an 18 awg core, you would be looking at the characteristic impedance, not the intrinsic impedance of the copper that will be carrying the waveform.

Variable dc supply is applicable in loads that are variable.

The imbalance of one goup over another (more of one then the other).

A Vacuum is the absence of air. So no, there is no air in a vacuum.

The metal lead. Solid at room temps, low melting point, good conductor of heat and electricity.

When generation kicks on, it can cause system voltage to rise, fall, or stay the same. Capacitors banks are used to help boost system voltage. Inductor banks are used to pull system voltage down.

In many situations, capacitor banks may be required to kick ON when generation kicks on - some wind turbines "suck in VARS", or act like inductors while pushing out power. This causes system voltage to sink, and must be counteracted using capacitors.

In your situation the distributed generation may be causing unacceptable voltage increases with the capacitor bank online.

we can draw an equivalent circuit for UJT USING a DIODE and two resistors.draw a diode in emitter lead ..draw the two resistors in series.As rb1 in base 1 lead ..and rb2 in base 2 lead ..draw rb1 as variable resistor.And put a voltage to the ujt in order to get a positive voltage in base two lead.

You do this carefully. It might be better to use a plug on a wire where the other end is bare (aptly named suicide cables), connect the oscilloscope, first to the bare wire (firmly), then plug into the wall. This will prevent potential arcing to your probes, which can be relatively expensive depending on your o-scope. I believe last time I looked, they can run upwards of $100 for a good one, so you don't want to ruin them. Make sure hands and equipment are dry.

An even BETTER way is to NOT look at the 120 volts directly, but through a step down transformer; this will keep the voltage at a safer level. If you do this, it's a good idea to fuse the primary connection so you aren't banking on your home breakers. Besides, why do you need to look at the 120v? On o-scope isn't going to show much, other than a nice pretty 60 or 50 Hz signal (harmonic content, flicker, etc. are very small, and if large will be very short lived - thus hard to catch).

Normally open and normally closed contacts are used in controls circuitry. They serve many functions.

Bad IGBT in the inverter

The field winding on a generator is the winding that is electrified to create an electromagnet; it is generally the winding found on the rotor (the rotating part of the generator).