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Q: How many watts of power does a resistance heater use operating at 460 volts and drawing 5 amps?

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2300

The formula you are looking for is W = E x I. Watts = Volts x Amps.

An electric heater is one of the high-power appliances in a house, commonly taking 1.5 to 3 kilowatts of power. The current is high, and therefore there is a drop in the voltage applied to the heater equal to the current multiplied by the resistance of the cord. There is probably little power wasted, because any heat from the cord goes to heat up the same room. But a voltage drop causes the heater to draw less current because its resistance is constant, and therefore less total power is provided to heat the room. If the heater is thermostatically controlled so that it is not working all the time, the difference is small because any reduction in the heater's power would cause the thermostat to keep it going for longer, to compensate.

With the same voltage across two conductors, the conductor with the smaller resistance will dissipate more power, i.e. generate more heat.

The resistance is equal to the voltage-squared divided by the power. So a 1kW heater is 52.9 ohms, a 100 watt bulb is 529 ohms. The basic formula is W = V^2 / R

Related questions

2300

The formula you are looking for is W = E x I. Watts = Volts x Amps.

An electric heater is one of the high-power appliances in a house, commonly taking 1.5 to 3 kilowatts of power. The current is high, and therefore there is a drop in the voltage applied to the heater equal to the current multiplied by the resistance of the cord. There is probably little power wasted, because any heat from the cord goes to heat up the same room. But a voltage drop causes the heater to draw less current because its resistance is constant, and therefore less total power is provided to heat the room. If the heater is thermostatically controlled so that it is not working all the time, the difference is small because any reduction in the heater's power would cause the thermostat to keep it going for longer, to compensate.

50 ohms...!

The length ,thickness, and alloy of the filament determines its resistance. The lower the resistance, the lower the voltage required to power it.

50

50 ohms...!

50 ohms...!

because before they were not dim The heater could be drawing too much power or your alternator isn't producing enough.

The two most important ratings for an electrical heater are its rated power and its rated voltage, and these will be printed on a 'nameplate' fixed somewhere on the heater (e.g. '3 kW at 230 V').For the heater to operate at its rated power, it must be subject to its rated voltage. In the above example, the heater will only operate at 3 kW if it is supplied with 230 V.If you know the heater's power (P) and its voltage (U), then you can calculate the rated current (I) it will draw from the supply, using the equation: I = P/U.You can also determine its resistance (R), using the equation R = U2/P.

Drawing power

ohms is a measure of resistance(R) in a circuit. Watts is a measure of the power(P), in this case lets assume it is the power used by the resistive element (lamp, heater etc). Power(watts)=Current(Amps)x Current(amps) x Resistance(ohms) or Resistance (ohms)=Power(W)/(current x current)

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