Controlling a reversable motor.

Thread Starter

hamgeek

Joined Apr 11, 2018
2
I've got one I've been working on until I blew out the imagination cells in my brain. I've been trying to design a motorized antenna mount for the luggage rack on my SUV. The idea is that a vertical antenna (only about 3' long) can be folded against the roof racks so I can park in those pesky low parking garages. I have what seems to be a windshield wiper motor (new and no markings) that has what appears to be some kind of switch which is a a piece of gold plated metal on the main plastic gear and two contacts on the cover. I was hoping to use that as a limit switch since I don't need a full rotation and probably going to gear down the output slightly for just a quarter rotation. The antenna mount would attach to the output shaft so it could go from horizontal to vertical and back. I made a circuit with relays and diodes that would work either direction but would get stuck at the end (not reverse direction). Also, I'd like only two wires going to this mess. The switches ("up" and "down") send power to the motor either polarity so it's independent of the car body (so is the antenna if anybody cares). The idea is to flip a switch (or press and hold a button) the antenna goes up and stops, flip another switch and the antenna goes down and stops. I'm trying to keep it simple, use what's available and the whole thing can be "removable" if need be. It would be so much simpler if there were two switches. sorry I don't have any diagrams to show. It's on the tip of my frontal lobe but I just can't quite get it. Any help kicking my brain in gear would be much appreciated.
 

MaxHeadRoom

Joined Jul 18, 2013
19,492
There a many different configurations of wiper motors many that operate in one direction only, this would be the type I would think would work best for you.
It would need some adjustment of the point of reverse, probably.
Or at least change the length of arm operator.
Max.

 

Thread Starter

hamgeek

Joined Apr 11, 2018
2
Thank you but it is one I already have. That was the whole point, to use what I had. This motor can run in both directions and the switch looks like it was supposed to trigger a circuit to reverse polarity. I'm beginning to think this is one for a rear window wiper. Smaller and not too fancy. Don't want to have to add my own limit switches but might have to go that way.

There a many different configurations of wiper motors many that operate in one direction only, this would be the type I would think would work best for you.
It would need some adjustment of the point of reverse, probably.
Or at least change the length of arm operator.
M
 

shortbus

Joined Sep 30, 2009
7,250
Thank you but it is one I already have. That was the whole point, to use what I had. This motor can run in both directions and the switch looks like it was supposed to trigger a circuit to reverse polarity. I'm beginning to think this is one for a rear window wiper. Smaller and not too fancy. Don't want to have to add my own limit switches but might have to go that way.
Just make sure that no matter what you end up doing that you test it before mounting on the cars roof. Windshield wiper motors are pretty powerful due to the worm gear in their drive train. They would be able to put a pretty good dent in your car roof it didn't work correctly.

And like Max said most of them only run in a complete rotation in one direction, Though they can be reversed by adding wires to the brushes. Though some do reverse a short distance, to "park" when shut off.
 
Top