A quick, electrifying tutorial pertaining to renewable energy:
Work, W = force x distance, ft-lbs (gm-cm); W = F · D
Example: Lift 100 lbs 10 feet; W = F · D = 100 lb · 10 ft = 1000 ft-lb (time to raise it doesn’t matter)
Power is the rate of doing work; P = work/time
P = 1000 ft-lb/ 10 seconds = 100 ft-lb/second
1 horsepower (HP) = 550 ft-pounds/second = 33,000 ft-lbs/minute
HP = W/(Tsec · 550) = W/(Tmin · 33,000)
P = E · I, P = I2 · R; Example: P = 120 V · 5A = 600 watts (W) (toaster ~900W)
746W electricity = 1 HP; 3413 BTU/kW
Energy is the ability or capacity to do work; energy and work have the same units
The work accomplished is equal to the energy expended.
Energy (Whr) = watts x hours; home electrical usage meters indicate kWh (kWhr)
Energy = power times time = P • t, where P is power and t is time
Ohm's Law: I = E/R, R = E/I, E = I · R (I is current, E is electromotive force, R is resistance)
Voltage Drop: V = I · R (V is voltage drop across a load)
Resistance in ohms = 1/conductance (conductance is measured in siemens)
Series R: Rtotal = R1 + R2 + ... + Rn
Parallel R: Rtotal = 1/(1/R1 + 1/R2 + 1/... + 1/Rn)
Electrolysis: H2SO4 (sulfuric acid) H+ SO4--, negatively charged cathode (-) attracts H+ ions --> H2; SO4-- ions attracted to anode (+); negative charge lost --> H2SO4 + O2
Lead peroxide, sulfuric acid, sheet lead; 2.2 V/cell discharged at specific gravity of 1.1, charged at specific gravity of 1.3
Joule's Law: Hcalories = 0.24 I2 · R x t
A transformer converts one voltage to a different voltage. Since the power is constant (except for losses), Pin = Pout = Vin · Iin = Vout · Iout
The ratio of wire turns on the input side, Nin, to turns on the output side, Nout determines the voltage change: Vin/Nin = Vout/Nout.
For example: 120V/1000 turns = Vout/2000 turns;
Vout = 2000 · (120V)/1000 = 120V · 2000/1000 = 240V because there were twice as many turns on the output (secondary) side.
The currents are Iin · Nin = Iout · Nout
For example: 2A · 1000 turns= Iout · 2000 turns,
Iout = 2A · 1000 turns/2000 turns = 1A. The current went down since the voltage went up.
Pin = 120V · 2A = 240W, and Pout = 240V · 1A = 240W (there would be some additional 1 to 5% loss in wire internal heating)
RenewableEnergy/GuideElectricity.htm updated 100111 by FRL