Electrical Wiring

Let R be the resistance, V the voltage, and I the current R = V / I R = 120 / 24 R = 5 ohm

This is a 15% overvoltage to the motor, which is generally outside the specifications for a motor spec'd at 208v (typically up to 10% overvoltage is tolerable). Your 240 volt source may be as much as 105% of 240 / 252 volts at times. A buck/boost transformer should be used, unless the motor is designed to be used at 240 volts.

Current transformer is a device used to measure the flow of current through a power system and the measured current is inputted to a protective relay system. It is used to detect system malfunction.

Current transducer is a device used to measure AC and DC current based on the halt-effect technology.

Only if you want to damage it.

"277" Volt 3-phase will usually mean 277 from each phase to neutral, and 480 from phase to phase.

By "230 3-phase", you likely mean 120 phase-to-neutral, and 208 phase-to-phase.

If you really mean 230, then you are probably NOT talking about a three phase motor.

First of all, your power source must be 3-phase if you want to run the motor, then you need a step-down 3-phase transformer to give 220v 3-phase output.

A Lincoln Tig 275 Welder typically requires around 9,000-10,000 watts to operate at full power. Therefore, a portable diesel generator with a minimum output of 10,000 watts or more would be recommended to run the welder efficiently without overloading the generator.

there are various types of trasformer tests are here

Open Ckt test

Short ckt test

IR value test

Vector group test

Phase sequence test

Magnetizing test

turn ratio test

T/f oil insulation breakdown test

and so on............

In a three phase power system, each phase is separated from the others by 120 degrees.

you would need a motor starter/contactor with the contactor coil rated at your control voltage. the motor is wired through the contactor main contacts and the control circuit wired into the contact coil

You start with a normal one way circuit consisting of a three phase contactor and an three phase overload in series for the forward circuit. Then you add the reverse contactor in parallel with the forward contactor but with line one and line two crossed over i.e. when the reverse contactor is made, line one of the supply will be connected to line two of the motor and line two of the supply to line one of the motor. The control circuit must also be interlocked to prevent forward and reverse being energized at the same time.

High-voltage transmission relies on the fact that for a given amount of power (watts), as the voltage goes up, the current (amps) goes down. The main issue with long distance transmission is voltage drop, which is proportional to current. Consider a transmission system supplying a 1 megawatt load. At 132,000 volts (3-phase), the current will be about 4.4 Amps (132kV X 4.379A X 1.73 = 1MW). Now, even 14 gauge wire would carry 4 or 5 amps, But the wire will have to be much larger than that to limit voltage drop to an acceptable level. The cost of the line itself is relatively small, BUT you have to buy transformers, one for each end! Utility-grade high voltage transformers are enormously expensive, and the hardware for high voltage transmission is also more expensive. Now consider a hypothetical transmission system supplying the same 1MW load, but now our transmission voltage is 4,160 volts. The current would now be 139 Amps! (4,160V X 138.9A X 1.73 = 1MW). You can see that the conductors must be very large to carry that much current. The problem is we still have to make the conductors larger to make up for voltage drop, and we end up with huge conductors. Of course, now you don't have to buy expensive high-voltage transformers! This is an extreme example just to make the point, by the way. At some distance, the cost of the transformers and associated hardware will equal the cost to eliminate them and just use larger conductors. At any distance less than that, it will be cheaper to use the low-voltage, high current setup. At any greater distance, the cost of the transformers, etc. will be more than offset by the cheaper transmission infrastructure (smaller conductors, etc.).

You Don't. 440volt 3-phase is actually 480 volts, taking a single phase gives 277Volts single phase.

To get single phase 440 you would use one leg of three phase 440/760 three phase power.

3 core 35 sq mm alu. Or 3 core 25 sq mm cup.

This seems like a question from an electrical course, and is probably best answered by your course materials. It's your test question, not ours, and there won't always be someone to ask the answer of. Earn your diploma.

The only relevant number is the kw. Then you just divide by the power factor to get the KVA. 0.8 is a pretty typical PF, so that would give you a KVA of about 9.4. But motors can take up to 5 times their rated current on start-up, so you need to make sure you have a generator that will handle that instantaneous current.

Three phase electricity, per watt delivered, is cheaper than single phase. This is because you can deliver the power to an electrical appliance over three "power lines" instead of one. For example, if you tried to operate a 5 hp ac electric motor on single phase it would require 3730 watts for continuous operation and quite a bit more for start up. A 12 gauge standard wire is only rated for 2700 watts. The more current that runs thru a wire the hotter it gets. The hotter it gets the more the resistance (ohms) goes up. Resistance in a wire is pure waste in terms of electrical cost since you are paying to convert electricity to heat. The same motor run on 12 gauge 3-phase wiring would only deliver 1243 watts per electric line to run the 5 hp motor. Also for motor use, three phase is much smoother and "torquier" than single phase since the power pulses to the field magnets is matched far better than in the single phase. For a visual on this see the website description below: = Wikipedia: Three-phase electric power =

Locked rotor amperage is the amperage the motor draws when the voltage is first applied to the motor and the rotor has not started to turn. This amperage is usually up to 300% of the motors running amperage. Once the rotor starts to turn the motor generates a back EMF (electro motive force) that opposes the high inrush current. This back EMF drives the amperage down until the motor gets up to its rated speed at which time the motor amperage will be at its run amperage.

A current transformer is primarily used at the neutral point of a transformer for earth fault protection.

A neutral current transformer will measure any ground fault current which will essentially flow from the star point of the transformer. A fault-detection device other devices is connected to the current transformer and, if the fault current exceeds a certain trigger value, the fault-detection device will give a trip command to an earth-fault relay to disconnect the supply of electricity to the transformer.

A standard household AC mains power supply, either 220-240 Volt 60 Hz or 50 Hz, is already a single-phase supply so it will not need to be converted. For more information please see the answers to the Related Questions shown below.

Question; If you were to ask the operator in a power plant to tell you how many mega watts the plant is generating; how would you ask?
Answer: How much load are you carrying?
Power plants do not generate electricity -- they carry load.