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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
230 volt motor be rewired to run on 208 volts?
Check the manufacturer's spec. You might be able to get away with this. Beware though, a reduced source voltage will manifest itself in a higher current draw, which results in an increase in heating.
What are voltage controlled voltage source?
when the magnitude of voltage of a source is controlled by another small voltage source in the circuit the former is called voltage controlled voltage source and the later is called controller voltage source.
A big one - one that can supply thousands (k) of V.A (not kva, but kV.A).
AnswerA volt ampere is used to measure apparent power (the vector sum of true power and reactive power. Transformers are rated in volt amperes, rather than in watts because to rate transformers in watts, it's necessary to know the power factor of the load, and transformer manufacturers have no way of knowing that.A kilovolt ampere (kV.A) is one-thousand volt amperes. Distribution transformers are typically rated in kilovolt amperes. For example, pole-mounted distribution transformers are typically 5 kV.A, 50 kV.A, etc., and are used to reduce high-voltages to residential low voltages.
Power transformers, used on transmission systems, are usually rated in megavolt amperes.
In a 3 phase 3 wire system what is the polarity of each conductor?
In a 3-phase 3-wire system, each conductor does not have a fixed polarity. The phase relationship between the conductors determines the direction of current flow, which can change over time as the phases alternate.
What is is the formula for calculating the full load current of 23KVA generator?
to calculate the motor full load current one should know motor power factor, supply voltage and phase of supply. Assuming your motor is with 0.85 pf and 3 phase, 415V source then P = (Sqrt3)*V*I*pf 18500 = 1.732*415*0.85*I hence I = 30.2A
10 kw used for 8760 hours equals what kwh?
Use the equation.
Kw x Hours = KWh
so take 10Kw multiplied by 8,760 hours and you get 87,600 KWh.
10Kw x 8,760 hours = 87,600 KWh
What happens when incoming 3 phase line is reduced to 1 or 2 phase?
Reducing a 3-phase line to 1 or 2 phases can lead to unbalanced voltages and currents in the system, potentially causing issues such as overheating of equipment, reduced power quality, and inefficient operation of three-phase motors. It can also result in uneven distribution of power among the phases, which may affect the overall performance and stability of the electrical system.
Not very bright at all. A 40W light bulb is about 450 lm, so a 55 lm source would be about 1/8th as intense as a 40W bulb.
How do you convert a one phase outlet to a three phase outlet to run my 3phase stove?
A three-phase service comprises three separate single phases. If you have a new branch circuit installed it can be connected to any one of the 3-phase lines and the neutral bus bar. That would be a single phase circuit and would have its own correctly-sized breaker, wiring and outlet(s).
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS. If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work
AND
always use an electricians test meter having metal-tipped probes
to insure the circuit is, in fact, de-energized.
How do you change ac tonnage to kva and kw?
To convert AC tonnage to kVA and kW, use the following formulas:
- For kVA: kVA = (tonnage x 3.517)
- For kW: kW = (tonnage x 3.517 x power factor). Remember to consider the power factor of the system when converting from tonnage to kVA and kW.
What gauge wire would you use to wire a 120V 20A motor?
For a 120V 20A motor, you would typically use a 12-gauge wire to ensure it can handle the current without overheating. This wire size is suitable for the amperage and voltage to provide proper insulation and safe operation for the motor.
Shock on a phase wire not on a neutral wire?
That's because the neutral is a grounded conductor.
AnswerThe line (not 'phase'!) conductor has a potential of 230 V (Europe) or 120 V (North America) with respect to the neutral, which is earthed (grounded) at the supply panel.
As you are more than likely 'earthed' (or 'grounded') by virtue of standing on it, this means that if you come into contact with a line conductor you will experience a potential difference of 230 V (or 120 V) between your point of contact with that line conductor and your point of contact with the earth, and you will receive a shock.
However, as the neutral conductor is already at, or close to, earth potential, should you come into contact with the neutral conductor, you will experience no (or very little) potential difference, and receive no shock.
How do you wire a 1 to 3 phase roto verter?
To wire a 1 to 3 phase roto verter, you will need to connect the single-phase power source to the roto verter input terminals (L1 and N). Then, connect the three-phase output terminals (R, S, T) to the load you want to power. Make sure to follow the manufacturer's wiring diagram and instructions for your specific roto verter model.
What is 400 amp 3 phase 380 volts converted to KW?
Whenever we specify voltages and currents in a three-phase system, unless otherwise stated, we always refer to line values. 'Lines' (or 'line conductors') are those conductors that connect a three-phase supply to its load.
So the '400 A' and '380 V' quoted in the question are line values (as opposed to phase values).
The equation for the power of a three-phase load is given by:
P = 1.732 x line voltage x line current x power factor
Since, in your question, you make no mention of power factor, we shall assume that the power factor is unity (i.e. the load is purely resistive) and, so:
P = 1.732 x 380 x 400 x 1 = 262 272 W (or 262 kW)
Why does amperage stay the same in a circuit?
Amperes represents a flow of charge (coulombs) in a circuit in a period of time (seconds). In order to have that flow, you have to have conductance, which is the inverse of resistance. Since the conductance of two circuits not connected to each other is zero (infinite resistance, neglecting leakage) there can be no current flow between disjoint circuits. A node is a junction between two elements in a circuit, such as the connection between a resistor and a light bulb. If you consider that the only circuit between those two elements contains that node, and that leakage is inconsequential in comparision to the conductance of the circuit, then you have to note that the current entering the node must be the same as the current leaving the node. In fact, this is Kirchoff's Current Law: The sum of the currents entering a node must equal the sum of the currents leaving a node. (Usually, we think of current entering to be one sign (+) and current leaving to be the other sign (-), so the sum of all currents relative to the node is zero.) Expand this thinking little by little to encompass the elements in the circuit. Again, there is no path for current to flow other than through the elements of the circuit. This means that the current in every part of the circuit is the same. Keep in mind that this applies only to series circuits. In a parallel circuit, current can branch out between two elements connected to a node supplied by another element. In that case, the current in each branch will be different, depending on the resistance and voltage of that path. Circuit analysis is simply the consolidation of a complex circuit into a simple circuit by repeated application of various conversions, such as Norton and Thevanin equivalents, with the ultimate goal of knowing the voltage, current, and resistance for each element.
What are the three phases of breathing?
The three phases of breathing are:
- The Active phase which is known as (inhalation/ inspiration).
- Phase 2. gas exchange in the lungs also known as (Internal exchange).
- The Passive phase which is known as (exhalation /expiration).
In induction motor the will the direction of the rotor will be in the direction of the current?
The direction an induction motor will turn depends upon the direction of the rotating field setup by the winding. Remember in AC the direction of the current reverses itself 120 times every second for a 60 hz system. So no it will not turn in the "direction" of the current.
KVA is very simple, it is the Volts x Amps of an AC circuit in units of 1000. For a single phase AC circuit VA = E x I. KVA = (ExI)/1000 So if you have 120 VAC and 15 A then: VA = 120 x 15 = 1800; KVA = 1800/1000 = 1.8 For 3 phase circuits we need to add the square of 3 (= 1.732) as a factor. VA = 1.732 x E x I and KVA = (1.732 x E x I)/1000 So if you have 480 VAC and 23 A then: VA = 1.732 x 480 x 23 = 19,121; KVA = 19,121/1000 = 19.1 Note that KVA is higher than KW (true power) in circuits that are not purely resistive. The vector difference of the two is "Power factor".
Convert single phase to three phase formula?
One common method to convert single phase to three phase power is by using a rotary phase converter. The rotary phase converter works by using a single-phase power source to generate a third phase, creating a balanced three-phase output. It typically involves using capacitors and an electric motor to create the additional phase needed for three-phase equipment.
When are Capacitors used with single phase motors?
The capacitor is used to produce a phase shift to create a rotating magnetic field so the motor will start turning. 3-phase motors do not need one because of the phase difference inherent between the phases.
While a capacitor connected external to the motor does affect the power factor of the overall system (as mentioned below), an internal start capacitor is not used for that reason in a single-phase motor.
Another answer
There is inductive reactance and capacitive reactance. (Look these terms up, it is good stuff). Think of them as opposites in a sense. The operation of the induction motor is inefficient in a power factor sense due to electro magnetic field properties that affect the power factor in an inductive sense. The capacitor is an "offset" to the inductive reactance which, when sized accordingly, affects the power factor as a correction towards unity.
The ohm is the unit of electrical resistance to current flow. More ohms (more resistance), the less current will flow. Less ohms (less resistance), the more current will flow. One ohm is defined as the amount of resistance that will cause one ampere of current to flow if the supply voltage is one volt. Ohm's law states that amps = volts / ohms So, if you had a 12 volt battery, and you connected a load, say a heating element that had a resistance of 3 ohms, how much current would flow in the circuit? amps = 12 volts / 3 ohms amps = 4
What is the anti-pumping scheme of Circuit breaker?
in order to stop the repetitive closure of the circuit breakers, anti pumping relay scheme is used. i.e suppose that an operator gives a close command to the breaker(via some switch), now the fault occurs, the breaker would tend to clear the fault and open the contacts.But since the operator has given the close command, it would cause closing of breaker again and again.. so anti pumping relay is used to ensure that this does not happen!
It is less confusing if we capitalize the units as required.
1 kVA = 1 kW, as originated from power [W] = current [A] * voltage [V].
The 'k' means 'times 1000'.
The statement can be re-written as 1000 VA = 1000 W.
Revolving field theory of single phase induction motors?
The revolving field theory of single-phase induction motors suggests that a rotating magnetic field created by current flowing through two windings (main and auxiliary or starting winding) produces a starting torque in the rotor. This theory explains how single-phase motors can operate without the need for a separate rotating magnetic field, as in three-phase motors, by using a split-phase or capacitor start design to generate a rotating magnetic field.
Why would three phase be used instead of single phase?
Three phase electricity is used instead of single phase for industrial situations. Industries use three phase electricity instead of single phase to operate electric motors driving heavy machinery. Three phase electrical motors produce more power from the same amount of electricity and maintain steadier speed. Small portable motors such as drills and mixers use single phase. Motors used around the house are single phase. Motors used to run large industrial machines use three phase.
