Electrical Engineering

because brass is generally tarnish resisant so it does not discolours easily and also because brass is not such expensive as copper

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The pins are make of brass because it is a harder metal than copper and will wear better through use over its lifetime.

When two identical 3v batteries are connected in series with the negative terminal of one of them in contact with the positive terminal of the other the total voltage of the combination is 6v.

analog signal

to control a high-current circuit with a low-current signal for example a starter on a car uses a very high current (not voltage) and needs thick cable to provide it.
it would be impractical to run this thick cable up to the ignition key so a lower current from the starter key operates a switch, usually electro magnet, which in turn completes a circuit for the higher current.

Yes

In parallel circuit , current entering into the circuit will be divided intodifferent paths ( resistances) . Amount of current flow depends upon the magnitude of resistance applied in the circuit. Total current after passing through the circuit will be the sum of all current through each resistance.

The value of internal resistance of 1.5 volt battery is 0.5 ohms.

well I had this same question on my homework, to check how many volts our household objects used up well the answer is

Laptop=12-16

Lamp=110

T.V=12 about the same as a laptop because it is blugged to the mains

It depends. If the system is a grounded or ungrounded Delta or ungrounded Wye connection (no neutral), then you need two. For an open Delta with a center-tapped ground, or Wye with a neutral, you need 3. Some monitoring systems also add a fourth, to measure ground current, although it is not needed to calculate power. Most measurement devices will accept up to 480V directly, for more than that you also have to add potential transformers in a similar fashion to reduce the mains voltage down to that range or lower for the system to measure the voltages.

You would have to apply a higher voltage from outside - for example, in the case of DC, connect a battery that provides more voltage, or connect more than one battery in series; or in the case of AC, use a transformer to increase the voltage.

The principle of LC tank ckt. which produces 180 deg phase shift the loop gain AB=1 in hartley oscillator are used 2 inductors and 1 capacitor.

Yes, but you have to use connectors designed for that purpose. Using ordinary wire nuts could cause a circuit failure due to a high resistive junction.

In order to determine what size of resistor is required to operate an LED from a 9V battery, first start by knowing the current and voltage required for the LED. That information is available in the LED's specifications.

For discussion purposes, lets assume a typical LED at 2.5V and 50mW. The translates to a forward current of 20mA.

Build a simple series circuit containing a 9V battery, a resistor of an as yet unknown value, and the LED.

By Kirchoff's current law, the current in the LED is the same as the current in the resistor, which is also the same as the current in the battery. This is 20ma.

By Kirchoff's voltage law, the voltage across the LED plus the voltage across the resistor equals the voltage across the battery. This is 6.5V. (9 - 2.5)

By Ohm's law, resistance is voltage divided by current, so the resistor is 6.5 / 0.02, or 325 Ohms. The nearest standard value to that is 330 Ohms.

Cross check the power through the resistor. Power is voltage times current, or 6.5V times 0.02A, or 0.13W. A half watt resistor is more than adequate for this job.

A single-phase load can be connected to a three-phase supply either by connecting it between any pair of line conductors or, for a three-phase, four-wire, system, between any line conductor and the neutral conductor -providing, of course, that the resulting voltage matches the requirement of the single-phase load.

This is quite a common arrangement, and the utility company will always try to maintain a reasonably 'balanced' load by connecting a number of single-phase loads between alternate line conductors (e.g. A-B, B-C, C-A, etc., or A-N, B-N, C-N, etc.).

So, to return to the question: 'What is the effect on a three-phase system if a single-phase load is connected to it?', the answer is that the three-phase system can normally deal with it without any problem.

this is because the energy can still flow through the other branches.

Transformers are used to step up and down voltages. The amount of this step is directly proportional to the turns ratio from one winding to the other. Using circular coils means a minimum amount of copper can be used, since the number of coils is relatively fixed by the voltage levels involved.

Another reason is corners are not a good idea when dealing with really high voltages - they can result in eddy currents, strange flux paths, corona, and localized heating to name a few problems.

ORGANIZER

A type of graphic organizer that helps you find general information about a character that you can organize and interpret later.

ELECTRICAL

A graphical representation of a machine circuit (analogous to Heyland Diagram).

denim coatis

The copper losses, because they vary as the square of the secondary/primary currents.

The short answer is you don't. More than likely you are looking at a three phase motor with three hot wires (to each be connected to a separate phase), one neutral and one ground (or earth). You need to connect up all five wires properly for it to run. Alternatively you could be looking at a three speed motor where each hot wire is for a different speed of the motor. In this case you'll need a three speed switch to connect it up.

It could be three phase, many swap and shops are full of three phase motors junked from closed plants and manufacturers and the seller has no idea what the motor is or came from, however, five wires as the question states, indicates the five wires come from the windings and none are chassis ground, leaving only four motor wires, in single phase, three wires could be a common, to one lead for one direction, and to another for the opposite direction and the remaining two wires could be external thermal leads, it could be multiple speed as noted above, in a single phase variety,

The problem with electric motors where the nameplate or connection plate is missing is problematic, as there are thousands of variations of motors, built for specific applications, if the question is what NEMA design 5 lead motor connections are, that could drill down the possible answers,

But back to single phase for a moment:

Single Phase Terminal Markings Identified By Color: (NEMA Standards)

1-Blue 5-Black P1-No color assigned

2-White 6-No color assigned P2-Brown

3-Orange 7-No color assigned

4-Yellow 8-Red

Most three phase NEMA motors are three, six, nine or twelve leads, rarely are the ends of each phase brought out, plus the neutral [internal wye connection only] and then a chassis ground, making a total of five.

Internally delta connected motors would not have a single neutral point, so those three phase motors that are connected delta internally are often just three, or if the need existed for a wye-delta external connection, then both ends of each phase would be brought out, the motor then would be connected externally with three wires in a bundle [electrically connected and isolated] using the last three to the incoming power, or if externally connected delta the delta points would be made up by taking the end of one phase to the beginning of the next, the end of the last to the beginning of the first.

Most chassis ground leads, [a lead connected to the motor frame] are not brought out with the power leads, to avoid confusion] normally the chassis ground is connected to a screw or through bolt, often colored green on the head of the bolt, and away from the terminal block or if in the terminal block positioned in such a manner it does not seem to fall into any possible "pattern" of the power leads.

Five lead motors [if ALL ARE WINDING LEADS] are fairly rare and generally special, for example most single phase would be two, three, four, or six, many are four power with one chassis ground.

It is important to note that any chassis ground wire needs to be absolutely identified as a chassis ground, [again, from a green screw and or colored green sheath]. Should a chassis ground be connected to the power source, it would be a straight short to ground from the power supply.

Identification of all the wires extending from the motor should be identified, by either use of an ohm meter, and in some cases, the only way to know is to remove the end housings and physically identify where the external leads are connected on the windings.

Because a capacitor is involved it is likely two of the five wires are dedicated wires for the capacitor, leaving two for power, and one as a chassis ground.

Normally if that is the case, the two leads for the capacitor are both colored the same and different from any of the other wires, brown being the most popular color for two dedicated capacitor leads.

My guess is this is a single phase motor with two to cap, two to power, and one is a frame or chassis ground, three phase with capacitor is rare and normally if a cap is used for a three phase motor, it is in a separate "box" the cap is used to form a "false" third leg and is used to create rotation, but is of little use past beginning rotation, these setups should be used with caution as the motor HP is usually derated by a significant factor, example 1/2 horse three phase with false third leg, may only be powerful enough to operate less than half the rated horsepower on a legitimate three phase power supply.

Again most likely two are for a capacitor, one is common, the other two are either speed choices with common, or reverse with common.

Only if you install separate switches for each part of the circuit. The whole point of a parallel circuit - is that both parts of the circuit are controlled by the same switch.