Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / 7anoter4
In a close circuit [in a loop] the current flowing in the
conductor produces a magnetic flux [F]. F=L*i [L=circuit
inductance, i=instantaneous current intensity].
In a.c. the flux will change from maximum positive to
maximum negative and again to maximum positive-ideal sine
wave form-in a full wave time-and in turn will produce a FEM
[equal to supply voltage-if we neglect the conductor
resistance].
v=L*di/dt -current derivate in time.
If i=Imax*sin(w*t)[ considering i=0 when t=0] w=2*pi()
*f f=frequency[50 or 60 Hz]
Simplifying: d(sin(wt))/dt=w*cos(wt) and d(cos(wt))/dt=-
w*sin(wt).
v=L*w*Imax*cos(w*t) if L*w*Imax=Vm then:
v=Vm*cos(w*t)
Since at time 0 voltage v=Vm but i=0 and i=Im will be
only after 1/4 of a wave , voltage leads the current.
In a condenser -capacitor-an electric field is installed
[if in the circuit is a voltage supplied ] and the plates
will be charged in short time accumulating the current. In
d.c. after the charge is finited no current will flow
further.
In a.c. a steady state current will flow following the
voltage variation.
From the relation :Q=C*v Q=electric charge C=Capacity
V=voltage
By definition i=dQ/dt then i=C*dv/dt
since v=Vm*cos(w*t)
dv/dt=-w*Vm*sin(w*t) i=-C*w*Vm*sin(wt) .
At t=0 i=0 but before this at wt=-pi/2 rad[-90 dgr] i=Im
that means current leads[the voltage].
90drg. lead=360-90=270 dgr. lag., of course. Conventional
we take only up to 180 dgr. for the angle between voltage
and current of the same phase.
| Is This Answer Correct ? | 8 Yes | 0 No |
Post New Answer View All Answers
WHY L-G FAULT IS MORE SEVERE IN TERMS OF RRRV?
What are the basic component of a cro?
In India the supply voltage is 230 volt A.C. During the negative half cycle phase becomes neutral and neutral become phase? or what will happen during negative half cycle? how the electrons flow during positive and negative half cycle?
how does ELR works? explain
Draw the DOL starter and star delta starter drawing?
Why can't we parallel Voltage transformer secondary circuits?
What is the Good Earth resistance value of G.I & Cu. Chemical Earthing & Normal Pipe Earthing?
What is the difference between electrical earthing and electrical grounding?
why the frequency and voltage in india is 230v and 50HZ. when compared to USA say 110v and 60 HZ.
An 8 pole, 50 Hz, 3-phase IM is loaded to a poing where pull out torque will occur. The rotor resistance per phase is 0.3 ohm and motor stalls at 650 rpm. The rotor reactance at stand still is A 2 ohm B 1.25 ohm C 3.15 ohm D 2.25 ohm
what are the analog quality input for protection function?what are minimum reqiments?
State the formula for overall efficiency of thermal power station
why actual valve timing diagram is different than ideal valve timing digram of a 4 stroke engine?
What is the difference between isolators and electrical circuit breakers?
If ROC does not lies inside unit circle,then ? a) Fourier transform converges b) Z transform converges c) Hatly transform converges d) Colpit Transform converges.
