The cable screen is non magnetic and can therfore be left in place but the earth for the screen must be returned through the ct for earthing.
With the cable earth screen intact the voltage level for the ct is .72/3kv.
If the cable is not screened the air between the cable and the ct will...
A 3 PHASE 400 AMP BREAKER CAN CARRY A MAXIMUM OF 400 AMPS IN EACH PHASE.
THERETICALY FOR A BALLANCED LOAD AS EACH PHASE IS 120 DEG APART THEY AD UP TO ZERO.
In an AC field the flux reverses in direction during each cycle. energy is lost in watts for this cycle and appears as heat.
If the cycle is interupted flux is left trapped in the core.
When a new cyle is started this remanent flux will effect the new cycle.
To prevent this when switching the...
Air is difficult to iliminate from insulation as it is in
tiny spaces within most materials.
at 50 volts per mil these spaces will not discharge and cause breakdown.
With special processing higher levels are achievable.
Typical breakdown figures for air
mm v/m
0.025 355.6
0.123 177.8
0.25...
The basic formula for Voltage is E = 4.44fBsAN volts
B = Peak FLUX DENSITY
A = area
N = turns
s = space factor
The constant 4.44 is 4 x 1.1 where 1.1 is the form factor for a sine wave.
A square wave would be 4 x 1 = 4
E/4.44fsAN = B = Peak FLUX DENSITY.
This may clear your vision ?
The basic formula for Voltage is E = 4.44fBsAN volts
B = Peak FLUX DENSITY
A = area
N = turns
s = space factor
The constant 4.44 is 4 x 1.1 where 1.1 is the form factor for a sine wave.
A square wave would be 4 x 1 = 4
E/4.44fsAN = B = Peak FLUX DENSITY.
This may clear your vision ?
Sorry for maths error corrections as follows
The MCSU burden at 8% setting is 0.03 ohms.
The pilots are 21 ohms.
The voltage developed is .08 x 1.9 x 21.03 = 3.2 volts
5VA CT 5P10 will be acurate to 1% of 1amp at 5 volts ie 0.01 amps(the actual current could be obtaind from a mag curve)
The...
Your calculations are well informed and accurate i would add the following comments
The MCSU burden at 8% setting is 0.03 ohms the pilots are 21 ohms the voltage developed is .08 x 1.9 x 21.03 = 3.2 volts
5VA CT 5P10 will be acurate to 1% of 1amp at 5 volts ie 0.01 amps(the actual current could...
The leakage flux in toroidal power transformer is negligable.
The inrush current at switch on can be very high (limited by primary resistance only) if core saturates.
To counter this the operating flux can be lower or a starting resister can be used.
The fault current is limited by resistance only
BS171 OR ANY POWER TRANSFORMER SPEC GIVES A TOLERANCE BETWEEN THE DECLARED TRANSFORMER RATIO AND THE TESTED TRANSFORMER RATIO AT NO LOAD.THIS VALUE IS SMALL AND CHECKED WITH ACCURATE INSTRUMENTS.(1%)
IN THE UK THE GRID TRANSFORMERS THAT ARE SOLIDLY EARTHED 132 KV AND ABOVE
HAVE 11 KV RATED INSULATION STAND OFF BUSHINGS THIS ENSURES THAT EARTH FAULTS FOLLOW A FIXED PATH TO EARTH VERY OFTEN THROUGH A PROTECTION CURRENT TRANSFORMER
