windscreen wiper motor problem
Hi
I am building a tank style robot which uses two windsreen wipers (one to run each track).
My problem is that when i try to put both motors running in the same direction( i.e one positively biased and the other negatively biased as they are faced in the opposite directions) the battery is shorted as the housings of these motors are grounded.
Those anyone know of a solution to this problem? or is there another kind of windscreen wiper motor that does not have the housing gounded?
Thanks
@ Sat, 2012-01-28 00:23
Heh. Yeah, necroposting is
Heh. Yeah, necroposting is the curse of forums. But the information you posted was very informative and valuable to someone who didn't know and needs to. Auto partss like these could stay on the surplus market, and keep coming out of junked cars for years. I really don't think you wasted anyone's time or bandwidth.
@ Fri, 2012-01-27 23:29
Wow. Look how old that post
Wow. Look how old that post was!
@ Fri, 2012-01-27 23:29
Done a bit of stuff with these
Yeah. I know this motor. It's actually one of the better ones: most use a direct worm gear. This one uses a worm gear driving a reduction gear. Much more efficient than Nissans / Fords, etc.
Oddbot is right. The only way you're going to drive one motor forward and the other one backward is by electrically isolating them and since the motors are -ve earth, you're snookered. My solution was to use a wooden chassis!
I do have one suggestion, but it's ropey and you aren't going to like it. You could use a 2-channel PWM drive, making sure that only one channel is pulsed at a time at no more than 50% mark to space. It means your max forward speed/torque is only half the capacity of the motor, though.
One ig ass-ache about these motors is that they run at different speeds backwards than they do forwards. Mine typically ran at 60RPM fwds and 50RPM bkwds. To get a straight line, you really need feedback.
@ Fri, 2010-04-23 10:58
took one apart
Hey
All i know is that they are from a 10yr old pug 106, there is no maufacturing number etc except a made in france stamp. I took one apart but as i am not an expert in motors i am not to sure with messing with the internals of it.
At the moment i am just controlling the motors straight from the battery, i then plan to control them with a PIC and a sabertooth motor controller board.
I can get the tank to drive around in a circle but its when i try to get it to go in a straight line it shorts the battery!
Any ideas greatly appreciated
@ Fri, 2010-04-16 11:31
Since most cars have the
Since most cars have the body grounded you will probably have to insulate your motors.
@ Fri, 2010-04-16 13:13
ThanksThat would be the
Thanks
That would be the correct way of doing it but there is a steel sprocket bolted onto the output shaft of the motors, that drives a chain so its not really possible.
i was wondering if there is some kind of modifications that could be made internally to the motor to prevent the housing from being grounded?
@ Fri, 2010-04-16 13:26
You will have to pull one apart and find out
Since you haven't told us exactly what motors your using (manufacturer, part number etc) and haven't posted any photos of your setup etc then how can anyone help.
Even if someone could tell you how to modify it then you would have to pull them apart to do it so I suggest you pull them apart anyway. If you can't work out to modify them then post clear high res photos so we can help.