Electrical Engineering

Volts

In what sense.

since at no load only excitation current(responsible for core loss ie iron loss) flow on the primary side so core loss current will be 1A and core loss = v1*i1*powerfactor. core loss = 1*11000*0.24= 2640watt.

well, not sure about the best services, i think the one which is affordable and reliable is the best one.

here are 3 services in Karachi that i know.

madni generator shop steel town Karachi, 03212002934

almustufa electrical engineering workshop saddar Karachi, 03009099339

gulshan generator repair services Karachi 03333421013

hope you find your best service

· It is not recommended for use above 70° Celsius although it can be taken to 80° for short periods. · Sensitive to UV and oxidative degradation. · Limited thermal capability. · Thermal decomposition evolves HCI. · Higher density than many plastics.

Posted By - Menteri (My)

If the switch is open, current does not flow.

The acceptable voltage on-site typically depends on the specific electrical system and equipment in use. In many residential and commercial settings, standard voltages are 120V or 240V in North America, while in other regions, 230V is common. For industrial applications, higher voltages such as 400V or 480V may be used. It's essential to follow local electrical codes and regulations to ensure safety and compliance.

Because alternating current (AC) voltage varies over time, to the positive and negative, an actual AC voltage measurement will not be the same as a DC voltage measurement. For example: 5 volts DC is 5 volts constantly, viewed over time. The average voltage is 5 volts. 5 volts AC (from zero to peak) is not actually 5 volts constantly, but varies between 5 volts and 0 volts over time. The average voltage will not be 5 volts. Using RMS AC values is designed to make AC and DC measurements equivalent, for example 5 volts DC and 5 volts RMS AC are almost identical.

to reduce the flow of current & keeping the current through galvanometer within safe limits.

Insulator. Like wood.

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AC to DC convertor. Or build your own with four diodes,reostat, and filters.

This type of circuit is known as a rectifier and is usually done with diodes, which block portions of the + and - cycles at a given point in time, allowing the other part of the cycle to pass. Rectification can be either full or half wave.

No

Yes, if you are talking about the normal carbon composition types having colour codes. But there are some non-linear types too.

If you're using it in reference to electrical service it generally means non-business hours. Off-peak electric service for instance is electric service that is at a much lower rate, however the electric company shuts off the service for a certain period of time each day, usually during the highest demand.

In electrical circuits series and parallel are two basic ways of wiring components. The naming comes after the method of attaching components, i.e. one after the other, or next to each other. As a demonstration, consider a very simple circuit consisting of two light bulbs and one 9V battery. If a wire joins the battery to one bulb, to the next bulb, then back to the battery, in one continuous loop, the bulbs are said to be in series. If, on the other hand, each bulb is wired separately to the battery it is wired in a parallel circuit.

The main wire in a bulb is the filament - which gets hot enough to give out light without burning away - and there are two other wires to take electricity to and from that filament.

Theoretically, Ohm's law says V=I*R where V is the Voltage, I is the current and R is the resistance. Consider a purely resistive load. As the resistance 'R' is fixed, above equation implies I=V/R.

Next, consider the way power is calculated: Power = V*I. Substituting I from above, Power = V*(V/R) = (V*V)/R. Assuming that R is constant, this implies that as you increase the voltage, the power increases by square of it. So, if one increases the voltage by 10% (say, from 100 to 110), The power increases from (100*100)/R to (110*110)/R, in other words, from 10000/R to 12100/R - an increase of 21%.

In general:

Increase by 5% in Voltage implies increased power consumption by 10%

Increase by 10% in Voltage implies increased power consumption by 21%

Increase by 20% in Voltage implies increased power consumption by 44%

Increase by 30% in Voltage implies increased power consumption by 69%

HOWEVER, please note that Resistance is a function of Heat as well. As a resistive load (like Incandescent Bulb) heats up on passing current, R actually decreases so actual savings may be slightly lower than above theoretical values. MOREOVER, not all loads are purely resistive - e.g., fans, refrigerators etc are inductive. So, some experiments suggest that net voltage drop of 10% lead to a power saving of about 14-20%, drop by 20% lead to 18-28% saving...depensing on the load composition and also the usage.

Many electric distribution companies across the globe try to increase the Voltage by up to 25% in low loss areas while decreasing it by similar amounts from permissible levels in high loss areas! This way, at the cost of consumer, they cover their losses.

Pinball games use complex arrays of series and parallel circuits. So do electric stoves.
But let's look at a simple one ... a toaster.

The toaster has several heating elements ... maybe four individual heating wires, one on each side
of the bread slot, and two bread slots in the machine. They're all in parallel ... one end of each heater
goes to one prong of the electric plug, and the other end of each heater goes to the other end of the plug.

BUT ... in series with one group of heater ends is a very important circuit element: the Switch.
When the switch is in a high-resistance state ("OFF"), no current flows through any branch in the
parallel section, i.e. the heaters remain cold. When the switch is in the low-resistance state ("ON"),
current flows through all of the parallel branches, and the result is toast.

In manual star delta starter, the change over from star to delta does not happen automatically. The operator or user puts on the starter, and after few seconds he pushes a lever or handle to change over to Delta.

In automatic method, change over happens from star to delta using an automatic preset timer.

Don't know of any three phase low voltage motors. Perhaps it's a "stepper motor". Stepper motors are typically computer controlled, with the computer pulsing different pairs of wire to cause the motor to "step".

What does the question refer to? Induction motors? Transformers? For transformers, the no-load voltage is the voltage -- across the secondary or primary -- when there is no load attached to the secondary, that is, when there is no current in the secondary. No-load current really only makes sense when talking about a motor, because current is flowing in the device even when it's not under load. A rule of thumb is the no-load current is about a third to one half the full-load current.

A 1000 watt device operated continusouly for 1 hour would equal 1 Kwh.