BossCat's Push Trailer

[BossCat]

I got a phone call from my mate telling me my motor had arrived, I nipped of to collect it

36V 500W Electric Motor Electric Bike, Scooter 2500RPM



After unpacking the motor my mate tested it on his battery booster (for jump starting cars), the motor span up, he then tested it on another booster, and finnally we tested it on a cordless drill batt. All three tests we suscessfull.
When I got home I further tested it on a Kinetic 12V 7ah/20hr battery I have, it was then a thought occured to me - Which way does the motor spin?

In this photo with the motor sitting on top of my trailer (just for demonstration purpose) the motor spins anticlock wise..



where as the trailer wheel below needs to turn clock wise to drive.

The only way I can now think of mounting the motor would be like this.....



With the motor just in front of the wheel, sticking far enough out to catch the chain line of the cog when I swap the trailer wheels around - so that the drive cog is on the outside.
The only other way I can think? is keep all as is and reverse the polarity + - on the motor so it spins clock wise?
QUESTION
Would reversing the polarity + - harm the motor?

Its the only thing I can think of when I see pictures like this...



Regards
Tom

[corgi1]

I would think the motor is made to run most powerful the right direction,and weaker reversed,,,,You may need to rearange the components in the trailer and put the motor on the same side as the one pictured above,and the pic above with the motor mounted on the ground would greatly limit the distance you could travel lol............Just my opinion

[rustymullet]

Smaller electric motors such as electric rc you can easily reverse motor to make it a pusher or puller type motor. I would think the same applies to a larger scale motor . It's all in the physics. rusty mullet

[BossCat]

Originally Posted by corgi1

I would think the motor is made to run most powerful the right direction,and weaker reversed,,,,You may need to rearange the components in the trailer and put the motor on the same side as the one pictured above,and the pic above with the motor mounted on the ground would greatly limit the distance you could travel lol............Just my opinion

I think you missed the point. In the picture below....
Bike - Trailer wheels and motor all running in an Aticlockwise direction as you look at picture.



If I set my trailer and motor up like that I would have my Bike - Trailer wheels running anticlock and my motor running clock wise, unless I reverse the polartity on my battery.

Thats why I was asking if any harm would be done or loss of power to the motor if I reversed the polarity.

To keep the polartity I would need to set my trailer up like Decon's PAT Trailer, with the motor on the other side of the trailer.....



Regards
Tom

[deacon]

The only time I ever had a problem running a motor backwards was when it had a clutch attached to the end of the shaft. Otherwise I have run them in either direction with no problem at all. I really like the attachment to the bike to make the hook up. It looks to be a hundred times stronger than mine was.

That little pusher of mine ran really nice, it would have been even better with 36v. Too bad I didn't keep it so that I could run it till it killed me lol.

I like your design for the trailer. I have gone with the classic support on each side of the wheel. the trailer is ugly as **** but it is stronger than a bull.

[zabac70]

Changing polarity won't hurt motor , if it is a brushless motor (DC). Performance would be the same either way. Some of these motors (don't know if it is the case with yours) have diode incorporated within them , but in that case if you switch "+" and "-" it just wouldn't work - no damage will occur. In that case something should be done with controller to reverse direction of rotation.

[deacon]

Be sure you switch the motor wires not the battery ones. I know you knew that but what the heck somebody might not.

[BossCat]

Originally Posted by deacon

Be sure you switch the motor wires not the battery ones. I know you knew that but what the heck somebody might not.

No I never knew that, plus I've no idea what you mean?

Motor has RED and BLACK wires coming from it. I hook up to a batt with RED wire to Pos and BLACK wire to Neg, motor runs clockwise. If I reverse the wires, RED wire to Neg and BLACK wire to Pos the motor runs anticlock wise like I want.

Anyway here's what's been done so far.
I stripped down a bike wheel and seperated all the cogs. I got my mate to weld a plate onto the cog then drill and file a hole so that the plate slips over the motor spindal. I then stripped the large cog of an old bike pedal and got my mate to weld the cog to a wheel. Wheel hooked everything up to a trailer and tested it. It ran ok if a little off center.

deacon
I like your design for the trailer. I have gone with the classic support on each side of the wheel. the trailer is ugly as **** but it is stronger than a bull.

Sadly the trailer pictured (i used for refrence) is not mine, I only wish it was.



The build for this trailer is here - Endless-sphere.com • View topic - Ross' bike pusher (trailer) project...

This is MY trailer....





This was the trailer before I changed the tow arm, I done this as I dont think that the little towball I have on the tow arm would hold up to the stress put on it by any motor.




I took the towarm off my monowheel trailer and attached it to my motor trailer as I thought this would be a stronger setup. After a test ride (no motor on, need to get batts) I found the bike unsteady and pulled to one side? I think this maybe because my mate welded the towarm a bit squint? Im going to try another steering stem under the angled plate to give the trailer rotation to see if it helps.



Regards
Tom

[corgi1]

================================================== ================
I took the towarm off my monowheel trailer and attached it to my motor trailer as I thought this would be a stronger setup. After a test ride (no motor on, need to get batts) I found the bike unsteady and pulled to one side?
================================================== ================
I am looking at the pic and asking did the bike pull left?,,,if it did the motor chain on this side may cause drag too the left.
I think the drag would be less if you could make the pivit for the hitch adjustable ,and could move toward the motor side of the trailer,,this would put the drag more directly behind the bike tire.

[corgi1]

Another Question? ,,does that hitch mount allow the bike to lean as you corner with out hindering free leaning of the bike?,,,