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
For electrical designers what are the standard should know? i want learn about this standards. how to get information/reference. anybody help in this regards please.
If I want to buy a new Xformer for my plant what are the main parameter will I need to check?
pls tel me the electric train traction motors name plate details like rpm,torue,voltage,amps,watts..ect..
What is the formula for calculating impedance of transformers connected parallel at fault level 50KA?
how can we save enegry by using VFD for Resiprocating Air compressor which is having more unloading running hours
I am getting above 60 V as open delta voltage against single phase unit ICT at tertiary delta formed and ICT getting trippped on NDR. ICT tested and found in order. PTs provided on tertiary are tested and in order. what may be the reason?
which pump used in WTP explain the function of VFD how to dtermine capacitorbank of capacity one plant
11000volt DG set carnt kaise banvay
What is a differential amplifier? Also, explain cmrr.
WHAT DO YOU MEAN THE DIFFERENT TYPE OF CURVES OF RELAY LIKE STANDARD INVERSE, VARY INVERSE, NORMAL INVERSE, LONG INVERSE ETC....
Why neutral cable carry current.
what kelvin's law ?
how to find the torque of the single phase synchronous motor by doing an experiment
When we use air circuit breaker, it has O/L protection ,time delay SC protection, Instataneous SC protection & ground fault protection. They all have some setting range. But what is the suitable/allowable setting for the above protection which will be safe for the equipment? For example-O/L protection setting have a range of (0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.8,0.9,1.0)xIn Time delay SC protection have a range of (1.25,1.5,2,3,4,6,8,10,12)xIn Time delay setting is 0.02,0.1,0.2,0.3,0.4 Instataneous setting is fixed to 20xIn Gound fault setting is given 100A,300A,600A,900A,1200A This setting are for 2500A ACB. So what will be the basic allowable setting for the above protection? is there any formulae to calculate this<
How can I calculate per unit (KWH) fuel (Gas/ Diesel both) consumption 1MW unit?
