Page 1 of 1
Changing polarity
Posted: Mon Apr 11, 2011 11:05 am
by Chris Edgar
On Saturday I watched a car being "flashed" to change to negative earth.
I was amazed at how simple it was.
One question which occurred to me later after I had left was...
"Why does the starter motor not run the other way round after the change"?
Chris
Re: Changing polarity
Posted: Mon Apr 11, 2011 1:35 pm
by bmcecosse
Because both the armature and the field windings still see the SAME polarity as each other - therefore - by Fleming's Left Hand Rule - the motor runs same way as before. Same with wiper motor and heater motor - although some claim to have seen a heater running backwards.....
Re: Changing polarity
Posted: Mon Apr 11, 2011 9:19 pm
by Chris Edgar
Ah, an example of a vector cross product!
Do you know, I had forgotten all that... it is well over 40 years ago.
Thanks,
Chris
Re: Changing polarity
Posted: Tue Apr 12, 2011 11:09 am
by mike.perry
I hope you did not miss the bit where the battery terminals were swapped
