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What is the difference between positive sequence and negative sequence arrangement?
The order in which the voltage of the coil reaches to the maximum value is called the Phase Sequence.
POSITIVE PHASE SEQUENCE: If the coil is rotated in anticlockwise direction, the phase sequence will be Positive Phase Sequence, i.e., R-Y-B or A-B-C.
NEGATIVE PHASE SEQUENCE: If the coil is rotated in clockwise direction, the phase sequence is called Negative Phase Sequence, i.e., R-B-Y or A-C-B.
NOTE: Phase Sequence is of great importance in parallel operation of three phase Transformers and alternators.
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What is zero sequence impedance in transmission line?
In symmetrical components, there are three types of impedances - positive sequence (balanced), negative sequence (unbalanced), and zero sequence (ground). In a transformer, positive and negative are equal. Ground impedance is determined by the (same factors as the) positive sequence and is based on the flux paths available through the transformer core that can induce ground current.
What is negative phase current?
Negative Phase Sequence is Phenomena generally found in motors,the formula for positive phase sequence is : Ip= Ir + a * Iy + a^2*Ibthe formula for negative phase sequence is : In= Ir + a ^2* Iy + a*IbAs the name suggest the sequence of current or the mmf is in reverse order, a reverse order current in stator will produce a reverse order mmf, now this reverse order mmf is rotating in direction opposite to the rotor of the motor, thus the mmf cut is very high and so current induced in stator is considerably high; as for normal mmf it is in direction of rotor so mmf cut is very small thus current induced is very small.this high current in your rotor leads to overheating of your motor and finally burning of your windings.CommentNegative phase sequence is not 'generally found in motors'. But one of the effects of negative phase sequence would be to cause a three-phase motor to reverse direction.
What is full wave bridge single phase inverter?
Did you mean inverter or rectifier? The description normally applies to the latter, and it is a device that turns both polarities of the applied alternating current to d.c. at one polarity. It's essentially two parallel half-wave rectifiers in opposition.
What kind of protections must be provided to 33kv electrical feeder?
Typical protection for a radial system would be overcurrent protection - a mixture of definite time, instantaneous time, and time overcurrent for positive sequence, negative sequence, and zero sequence is usually used (negative sequence isn't used very often, but there are times when it is needed). These overcurrent protective devices will trip a breaker, circuit switcher, or similar device. When feeds become extremely long, sometimes in-line fusing is used part way down the line as a cheap alternate to a recloser or breaker. The drawback is if a fault occurs, someone has to go out and replace the fuse, and you are typically at the mercy of the customer calling in and complaining before you will know a fuse is blown.
What is neutral negetive sequence current?
Negative sequence current is defined as 3I2 = (phase 1)*(1angle 0) + (phase 2)*(1angle 240) + (phase 3)*(1angle 120) Negative sequence current is seen in three phase power systems due to natural system imbalance. Also during unbalanced fault conditions such as line to line, Line to ground, and line to line to ground faults. It is not seen in purely balanced three phase faults.
The common difference in an arithmetic sequence is a positive number?
could also be negative
How can you determine whether the arithmetic sequence has a positive common difference or a negative common difference?
If the terms get bigger as you go along, the common difference is positive. If they get smaller, the common difference is negative and if they stay the same then the common difference is 0.
What is the difference between an arithmetic sequence and a geometric sequence?
In an arithmetic sequence the same number (positive or negative) is added to each term to get to the next term.In a geometric sequence the same number (positive or negative) is multiplied into each term to get to the next term.A geometric sequence uses multiplicative and divisive formulas while an arithmetic uses additive and subtractive formulas.
Does there exists any sequence whose limit is positive but sequence is negative?
No, such a sequence is not posible.
Explain how to find the common difference of an arithmetic sequence How can you determine whether the arithmetic sequence has a positive common difference or a negative common difference?
For any index n (>1) calculate D(n) = U(n) - U(n-1). If this is the same for all integers n (>1) then D is the common difference. The sign of D determines whether the common difference is positive or negative.
How do you find the nth term of decreasing linear sequence?
The answer depends on what information you have. If you know the first number, a, and the common difference d, (where d is negative), then the nth term is a + (n - 1)*d : exactly the same as in an increasing linear sequence. The only difference is that d is negative instead of positive.
In an arithmetic sequence if the difference value is negative what is the effect?
It creates a decreasing sequence.
How do you derive negative sequence impedance of an earthing transformer for 11 KV delta connected 10 MVA source transformer?
Negative sequence and positive sequence are the same for a transformer. You would derive using the same connections as done to calculate the positive sequence impedance. Usually the test report will give positive, and often zero sequence impedances (sometimes left off, depending on the type of transformer as the zero sequence sometimes is the same as the positive sequence). The negative sequence is never given to my knowledge, because it is redundant and unnecessary test.
How do I find the nth term of a decreasing linear sequence?
Whether the sequence is increasing or decreasing makes no difference. The only difference is that the common difference d will be a negative number.
What sequence do I use to connect a car battery?
Connect positive first, negative last.
Why do the points of a geometric sequence lie on an exponential curve only when the common ratio is positive?
If the common ratio is negative then the points are alternately positive and negative. While their absolute values will lie on an exponential curve, an oscillating sequence will not lie on such a curve,
What does descending in algebra mean?
Descending (in a sequence) means that a the next number is "more negative" or "closer to negative infinity" or "less positive" or "further from positive infinity" or if n is a number in a sequence and n+1 is the next number then n/n+1 > 1
