# Basic question on right hand slap rule and electric motor

1. Jul 14, 2008

### sameeralord

Hello guys,

First of all I have small question with the electric motor. I just learned today in class that with electric motor loops the current is reversed in the loop after 180 degrees to continue a constant movement in one direction. But my question is why is this nessecary. If we don't have this the loop would spin back and forth. Isn't this a change in magnetic flux. So why do we have to have constant one direction rotation. Other quetsion is simply about right hand slap rule. We use the magnitic field experienced by the current in this rule don't we. I mean let's say they gave us the current. We don't then have to work out the magnetic field by the right hand grip rule and then use right hand palm rule. I'm assuming this magnetic field we work out from right hand rule is not experience by the current so we don't use that in the rule. We use the magnetic field it experiences. For example when it is inside a magnet. I hope you understood what I was saying. Anyhelp as always would be much appreciated

2. Jul 14, 2008

### tiny-tim

producing linear motion

Hi sameeralord!

Yes, I suppose the motor would work ok without the reversal …

but it wouldn't have a useful output.

If the motor turns the same way all the time, you can join it to a turbine or a wheel, and produce linear motion.

If the motor keeps reversing direction, all it can be used for is rocking cradles etcetera.

3. Jul 17, 2008

### sameeralord

Re: producing linear motion

So it is for practical purposes. Thanks a lot for your help .

If the motor keeps reversing direction, all it can be used for is rocking cradles etcetera.

lol good one:rofl: