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 NETIK-CAD Electrical blocks for Autocad ®

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EXPLANATION ABOUT THE SYMBOLS
TUTORIAL ON CREATING THE MENU'S
SYMBOLS LIST
DATABASE
SCHEMATIC
MEMENTO-1 GENERAL
MEMENTO-2 CABLES
MEMENTO-3 MOTORS
MEMENTO-4 FORMULA
MEMENTO-5 BELGIAN ELECTRICAL INSTALLATION NORM
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Memento - 4    Electric formula

 
Electric formula
 
 
Voltage drop in direct current with known power value : u = 2.L.P / (S.U) [V] u = Voltage drop [V]

U = Voltage [V]

I = Current strength [A]

P = Power [W]

L = Length of cable [m]

S = Cross section of wire [mm²]

Voltage drop in direct current with known Current strength : u = 2.L.I / S [V]
     
Alternative current monophase u =2.L.r.(I.cos f) / U [V]  
     
Alternative current triphase u = (3)½.L.r.(I.cos f) / U [V]  
     
Magnetic field produced by a coil of n windings with a current strength I H = n.I / L [A/m]

n = Number of windings

I = Current strength [A]

L = Length [m]

Magnetic induction B = µor.H [T]

µo= 4.p.10-7

µr= Magnetic relative permeability of the material

magnetic flux quantum f = B.S.cos a [Wb]

B = Magnetic induction [T]

S = Area [m²]

a = Angle between B and S

Electromagnetic force F = B.I.L.sin a [N]

B = Magnetic induction [T]

I = Current strength [A]

L = Length [m]

a = Angle between B and the conductor

Dynamic force between 2 // conductors F = 0,2.I1.I2.d.e [N]

I1 = Current strength of conductor 1 [A]

I2 = Current strength of conductor 2 [A]

d = Distance where the 2 conductors are // [m]

e = Spacing between the 2 conductors [m]

Pulsation w = 2.p.f [rad/s]

p = 3.1415

f = Frequency [Hz]

Frequency f = 1 / T [Hz] T = Period [s]
Voltage drop U = R.I [V]

R = Resistance of the conductor [W]

I = Current strength [A]

Resistance R = r . L / S [W]

r = Resistivity of the conductor [W.m]

r of cooper at 20°C = 17,24 10-6 [W.m]

L = Length [m]

S = Cross section of the conductor [m²]

 

Active Power in triphase S = 1,732.U.I [VA]  
Active Power in triphase P = 1,732.U.I.cos f [W]  
Reactive Power in triphase Q = 1,732.U.I.sin f [VAr]  
Relation between powers S2 = P2 + Q2 [VA]  
     
Moment

M = ML+Ma [Nm]

M = ML+(p/30).J.(Dn/ta) [Nm]

M = Motor moment [Nm]

ML = Load moment [Nm]

Ma = Acceleration moment [Nm]

J = Global mass moment inertia [kg m²]

Dn = Differentiel speed [m-1]

P = Motor power [kW]

PL = Load power [kW]

Pa = Acceleration power [kW]

ta = Time of acceleration necessary to go up of the differential speed [s]

Acceleration moment

Ma = (p/30).J.(Dn/ta) [Nm]

Ma = (0,105).J.(Dn/ta) [Nm]

Work - Energy

W = (p2/1800).J.(Dn2).M / (M-ML) [Nm]

W = J.(Dn2).M / (182,4.(M-ML)) [Nm]

Total power P = PL+Pa [Nm]
Acceleration time

ta = (p/30).J.Dn/(M-ML) [s]

ta = 0,105.J.Dn/(M-ML) [s]

ta = p2.J.Dn2/(9.105.(P-PL)) [s]

ta = J.Dn2/(9,12.104.(P-PL)) [s]

     
Impedance Z = U / I [W]  
Impedance of a winding

Z = L.2.p.f [W]

Z = L.314,16 [W] at 50Hz

 
Impedance of a capacity

Z = 1 / (C.2.p.f) [W]

Z = 1 / (C.314,16) [W] at 50Hz

 
Synchronizing speed of an asynchrone triphase motor

ns = 2.60.f / p [r/min]

f = Frequency [Hz]

p = Numbre of pole per phase

ns ( at 50Hz)
p
1500
4
1000
6
750
8
375
16
250
24
     
Power

1 HP = 0,73549 kW = 0,74 kW

1 kcal/h = 1,163 W = 1,16 W

1 kcal/h = 4,1868 kJ/h = 4,2 kJ/h

 
Energy 1 kcal = 4,1868 kJ = 4,2 kJ