SERIOUS ANSWERS ONLY PLEASE! On an electric motor, what's the difference between volts and watts?

Question

Bzzzzzzzzzzz.........

Answer 1

The three most basic units in electricity are voltage (V), current (I) and resistance (r). Voltage is measured in volts, current is measured in amps and resistance is measured in ohms.
A neat analogy to help understand these terms is a system of plumbing pipes. The voltage is equivalent to the water pressure, the current is equivalent to the flow rate, and the resistance is like the pipe size.

There is a basic equation in electrical engineering that states how the three terms relate. It says that the current is equal to the voltage divided by the resistance.

I = V/r

Let's see how this relation applies to the plumbing system. Let's say you have a tank of pressurized water connected to a hose that you are using to water the garden.

What happens if you increase the pressure in the tank? You probably can guess that this makes more water come out of the hose. The same is true of an electrical system: Increasing the voltage will make more current flow.

Let's say you increase the diameter of the hose and all of the fittings to the tank. You probably guessed that this also makes more water come out of the hose. This is like decreasing the resistance in an electrical system, which increases the current flow.

Electrical power is measured in watts. In an electrical system power (P) is equal to the voltage multiplied by the current.


P = VI
The water analogy still applies. Take a hose and point it at a waterwheel like the ones that were used to turn grinding stones in watermills. You can increase the power generated by the waterwheel in two ways. If you increase the pressure of the water coming out of the hose, it hits the waterwheel with a lot more force and the wheel turns faster, generating more power. If you increase the flow rate, the waterwheel turns faster because of the weight of the extra water hitting it.

In an electrical system, increasing either the current or the voltage will result in higher power. Let's say you have a system with a 6-volt light bulb hooked up to a 6-volt battery. The power output of the light bulb is 100 watts. Using the equation above, we can calculate how much current in amps would be required to get 100 watts out of this 6-volt bulb.

You know that P = 100 W, and V = 6 V. So you can rearrange the equation to solve for I and substitute in the numbers.


I = P/V = 100 W / 6 V = 16.66 amps
What would happen if you use a 12-volt battery and a 12-volt light bulb to get 100 watts of power?


100 W / 12 V = 8.33 amps
So this system produces the same power, but with half the current. There is an advantage that comes from using less current to make the same amount of power. The resistance in electrical wires consumes power, and the power consumed increases as the current going through the wires increases. You can see how this happens by doing a little rearranging of the two equations. What you need is an equation for power in terms of resistance and current. Let's rearrange the first equation:


I = V / R can be restated as V = I R
Now you can substitute the equation for V into the other equation:


P = V I substituting for V we get P = IR I, or P = I2R
What this equation tells you is that the power consumed by the wires increases if the resistance of the wires increases (for instance, if the wires get smaller or are made of a less conductive material). But it increases dramatically if the current going through the wires increases. So using a higher voltage to reduce the current can make electrical systems more efficient. The efficiency of electric motors also improves at higher voltages.

This improvement in efficiency is what is driving the automobile industry to adopt a higher voltage standard. Carmakers are moving toward a 42-volt electrical system from the current 12-volt electrical systems. The electrical demand on cars has been steadily increasing since the first cars were made. The first cars didn't even have electrical headlights; they used oil lanterns. Today cars have thousands of electrical circuits, and future cars will demand even more power. The change to 42 volts will help cars meet the greater electrical demand placed on them without having to increase the size of wires and generators to handle the greater current.

Answer 2

Picture electricity as water. Volts are the water's pressure. Amps are the water's volume. Watts are the water's power or ability to do something like put out a fire using its volts and amps. Like a water hose with an adjustable nozzle, when you make the nozzle smaller, the water comes out with more pressure (volts). When you make the nozzle bigger, the water comes out with more volume (amps). Electricity is the same. High voltage will arc through the air but unless it has some current too, it is harmless like static electricity. High current will melt a wire but without some voltage it's harmless, like your car battery. The formula for figuring power is P (in watts) = Volts X Amps. A 12 volt battery that puts out 5 amps can make 60 watts of power. Take the battery voltage up to 24 volts and you can get 120 watts of power. That's why portable drills with higher voltage batteries can make more power.

Answer 3

Serious answers only? On here? ;-)

On a car, what's the difference between feet and pounds?

That's the kind of question you asked, because volts and watts measure different things, and it has nothing to do with motors. Maybe you need to ask a different question to get what you want.

Volts measure voltage (potential difference, electromotive force). It is a little harder to explain, but think of it as a measure of an electric force that causes electricity to move.

Watts measure power, and can be any kind of power, not just electric. Power is energy used per unit time. A joule is a measure of energy, and a watt is 1 joule per second. A joule can also be called a watt second. Your home electric usage is in watt hours (or kilowatt-hours), a measure of energy.

What does this have to do with a motor? A motor will have a voltage rating, typically meaning you can damage the motor if a voltage outside its rating is used. Motors are normally measured in horsepower (like the watt, it is a power rating) which indicates how much power it can provide. Loses in a motor mean the electric power used will be more than the mechanical power produced, and the HP rating of a motor is the output power.

Answer 4

Let me try a simple answer. Volts is the size of electrical force powering the motor. Watts is the amount of electricity that the motor consumes while running.

Answer 5

The definitions are:
1 joule = the energy generated when 1 ampere of electrical
current, passes through an electrical potential drop of 1 volt. Energy =
Volts x Current.

1 watt = 1 joule/second.

So joules is a quantity of energy, and watts is the RATE of generation of
energy. Watt = Energy / second.



Hope I helped!!!

Answer 6

Look up Ohm's Law. It states that Voltage (E) equals Current (I) times resistance (R). It also states that Power (P) equals Current (I) times Volatge (E)

E=IR and P=IE

Voltage (E) is called electromotive force. Think of it as electrical pressure analagous to water flowing through a hose. It causes the electrons (Current) to flow through the copper wires.

The wires themselves, and any load such as a motor, have resistance to the flow of current. This generates heat.

Power measured in Watts is the amount of energy consumed by the load.

To answer your specific question; On an electric motor, the resistance of the motor windings determines the operating voltage needed to produce the intended horsepower. for additional information; 746 watts equals 1 horsepower.

Answer 7

A volt is unit of potential equal to the potential difference between two points on a conductor carrying a current of 1 ampere when the power dissipated between the two points is 1 watt; equivalent to the potential difference across a resistance of 1 ohm when 1 ampere of current flows through it

A Watt is a unit of power equal to 1 joule per second; the power dissipated by a current of 1 ampere flowing across a resistance of 1 ohm.
So volts is the current, watts is the power used.

Answer 8

I'm not a rocket scientist but I have to believe that volts is what it takes to operate the motor...Watts is what it produces in its operation,,, That might be especially true of a generator, which takes a certain number of volts of power to create the necessary watts to offer power to appliances etc.

Rev. Steven

GOOD not GOD

Answer 9

Some good answers but hers some more, you can find the watts on a plate on the motor then divide the watts by 230 and it will tell you how many amps it takes to run it.

Answer 10

well on a electric motor voltage is what it takes to run it and watts is whats it can put out kinda like a light bulb it takes 120 volt to run but it puts out a certain amount of watts.