# Electric Current

on . Posted in Electrical Engineering

Electric current, abbreviated as I, is the flow of electric charge in a circuit or a conductor.  The current flow is caused by the movement of electrons, which are negatively charged particles, through a conductor such as a wire.  The rate of flow of electric charge (current) is typically determined by the voltage (potential difference) applied across the conductor and the resistance of the conductor.  The relationship between voltage, current, and resistance is described by Ohm's Law, which states that the current through a conductor is directly proportional to the voltage applied across it and inversely proportional to its resistance.

### Electric Current formula

$$I \;=\; V \;/\; R$$     (Electric Current)

$$V \;=\; I \; R$$

$$R \;=\; V \;/\; I$$

Symbol English Metric
$$\ I$$ = current $$I$$ $$C \;/\; s$$
$$V$$ = voltage   $$V$$ $$kg-m^2 \;/\; s^3-A$$
$$R$$ = resistance $$\Omega$$ $$kg-m^2 \;/\; s^3-A^2$$

### Electric Current formula

$$I \;=\; P \;/\; V$$     (Electric Current)

$$P \;=\; I \; V$$

$$V \;=\; P \;/\; I$$

Symbol English Metric
$$I$$ = current $$I$$ $$C \;/\; s$$
$$P$$ = power $$P$$ $$kg-m^2 \;/\; s^3$$
$$V$$ = voltage $$V$$ $$kg-m^2 \;/\; s^3-A$$

### Electric Current formula

$$I \;=\; \sqrt{ P \;/\; R }$$     (Electric Current)

$$P \;=\; I^2 \; R$$

$$R \;=\; P \;/\; I^2$$

Symbol English Metric
$$I$$ = current $$I$$ $$C \;/\; s$$
$$P$$ = power $$P$$ $$kg-m^2 \;/\; s^3$$
$$R$$ = resistance $$\Omega$$ $$kg-m^2 \;/\; s^3-A^2$$

### Motor Current Formulas

$$V$$ = Voltage  -  $$I$$ = Amps  -  $$PF$$ = Power Factor  -  $$\eta$$ = Efficiency  -  $$P$$ = Power

To Find Direct Current Alternating Current
Single Phase Two Phase Four Wire Three Phase
Curremt $$\large{\frac{ P }{ V \; \eta } }$$ $$\large{\frac{ P }{ V \; \eta \; PF } }$$ - $$\large{\frac{ P }{ 1.732 \; V \; \eta \; PF } }$$

### Amps to Horsepower formula

$$HP \;=\; (I \; V \; \eta \; PF) \;/\; 746$$     (Amps to Horsepower)

$$I \;=\; (HP \; 746) \;/\; (V \; \eta \; PF)$$

$$V \;=\; (HP \; 746) \;/\; (I \; \eta \; PF)$$

$$\eta \;=\; (HP \; 746) \;/\; (I \; V \; PF)$$

$$PF \;=\; (HP \; 746) \;/\; (I \; V \; \eta)$$

Symbol English Metric
$$HP$$ = horsepower $$lbf-ft\;/\;sec$$ $$C\;/\;s$$
$$I$$ = amps $$I$$ $$kg-m^2\;/\;s^2$$
$$V$$ = voltage $$V$$ $$kg-m^2 \;/\; s^3-A$$
$$\eta$$ (Greek symbol eta) = efficiency $$dimensionless$$
$$PF$$ = power factor $$dimensionless$$

### CONVERSION formulas

kVA (kilovolt-amps) = 1000 volt-amps

KVA to Amps Formulas

$$I \;=\; (kVA \;/\; V) \; 1000$$     (Single Phase)

$$I \;=\; (kVA \; 1000) \;/\; \sqrt{3} \; V$$     (Three Phase - Line to Line)

$$I \;=\; (kVA \; 1000) \;/\; (3 \; V)$$     (Three Phase - Line to Neutral)

AMPS to KVA Formulas

$$kVA \;=\; (V \; I) \;/\; 1000$$     (Single Phase)

$$kVA \;=\; \sqrt{3} \;\; V \; I$$     (Three Phase - Line to Line)

$$kVA \;=\; 3 \; V \; I$$     (Three Phase - Line to Neutral)

Kilowatt-hours to Amp-hours Formula

$$Ah \;=\; (kWh \; 1000) \;/\; V$$