[stoner]

hy i,ve just reired my track to club specs, positive polarity. i,,ll try to explain the problem. viewed from me standing in front of a straight. press the trigger the cars go left. put a lightbulb tester on the - side of psu and furthest track rail and when i push the controller it lights up..... so i presumed the furthest rail was the +. problem is when i put just a motor leads on to the track, red from motor to farthest rail and black from motor to the nearest rail, the motor runs backwards when i press the trigger,and the light is still on to the farthest rail, which i presumed was the red to the motor.will any one explain it to me. john

 

[zendragon]

this is correct as the motor turns in a clockwise direction when viewed from behind turning the crown wheel clockwise also when viewed from drivers side or offside on real car.
simples
Zen

 

[RichD]

When you are talking about how a track is wired polarity actually refers to the direction that electricity goes through the controllers, not the direction the cars will run on the track. 1/32nd and 1/24th tracks are wired so that the right hand rail is positive looking in the direction of travel.

 

[300SLR]

"Positive polarity" most often refers to which way the current passes through the controller. This is important with electronic controllers but doesn't matter with resistance controllers.
Which direction the car travels is completely separate.

From what you say, I think your track is wired to positive polarity.
If I understand the description correctly (and I'm not sure about that) it sounds like the track is wired for the normal direction of travel.
I might have misunderstood the description - but are sure the red and black wires on the motor are the right way round?

 

[stoner]

zendragon, thanks for trying to be helpfull, but i had a hard time understanding what you where getting at. i know the majority of motors run CW, unless you can see which way the timing advance is,check em on a speedo and see which direction is faster.offhand i can only think of 2 motors which run CCW, the falcon 2 and the proslot euro motor with an american arm. my problem is,? useing a slot it motor and leads, the rail that lights up when i press the controller seems to be negative. so placing the red lead from the motor on the piece of lit track and the black lead to the other rail, causes the motor to run CCW taking the motor to the psu and applying power, it runs CW, so its not as simple as crossing the motor wires as the track seems to power the motor from the negative rail. which if its right, will damage all my motors with any advanced timing. ive been over the wireing diagram a dozen times, and it seems okay. so whats the next step. john

 

[roblees]

Joh n did you use the wiring diagrams on the tech pages of the BSCRA website. If your wiring is correct but the cars/motors don't run in the direction you want, only reverse the connections at the track - the direction of travel will then be reversed.

 

[stoner]

i used the wireing diagram from a recent forun topic and chris frost. i put DPDT switches in the circuit to reverse travel, curtesy of old weird harold. but the problems the same. the rail that lights up when you press the controller doesnt feed the motor. its the unlit lane that supplies the right power to spin the motor CW. john

 

[300SLR]

Agreed - having the motor rotating the right way to take advantage of commutator advance is important.
(Of course that only matters if the motor has commutator advance - A lot of low end motors symmetrically timed, so they work equally well either way round)

The important thing to understand is that the direction of motor rotation is all about the mechanical arrangement. Let's look at the detail

The direction of motor rotation can be reversed by fitting the pinion on the other end of the motor (swap can end drive for endbell drive to can end drive or vica versa) Obviously this is only practical if there is enough shaft length at each end of the motor, and the motor will fit the chassis the other way round.

In an inline, putting the crown wheel on the other side of the pinion reverses direction of motor rotation.

In an anglewinder, which way round the chassis is built defines the gear position so swaping can end drive / endbell drive is the the only way to reverse the motor rotation.

A sidewinder is the same as an anglewinder, unless it possible to mount the gear on opposite side of the chassis - which reverses direction of motor rotation.

Obviously the lead wires need to be wired the correct way round so the car goes forward.

 

[Thatcedric]

The car goes the direction I would expect, left. So no problem there. as mentioned earlier, CW & CCW is a matter of viewpoint not an absolute.

 

[RichD]

This is what is referred to as positive polarity.

As you described things in your first post for the cars to go left the rail closest to you would have to be negative. I can't recall seing a motor that was marked with positive and negative wires. As has been said before a lot of motors made for 1/32nd scale cars have neutral timing and will have the same performance no matter which direction they are run. Looking at the motor from the endbell end the right hand connection has to go to positive if the pinion gear is on the endbell end.

 

[stoner]

thanks rich, i,ve been i,ll so i,ll recheck it this morning and let you know the results. john

 

[stoner]

i,ve cheched it and the wireing is correct positive polarity. i just have to change the motor wires over to make the motor spin cw and travel in the right direction.. still dont under stand why! if i put the positive lead from a motor onto the poitive track rail it spins ccw, such are the vagaries of life for an electrics moron. thanks for your help. john.

 

[RichD]

What end of the motor is the pinion gear on? If the pinion was moved to the opposite side the wires would have to be reversed. Another option is to open up the motor and swap the magnets around.

 

[stoner]

all? the mainstream cars are wired for reverse polarity tracks, so i,ve only got to reverse the leads from pick up to motor to make them run right. same for scatchbuilds, all the newer motors, slot it, nsr ect have a red spot on the poitive side of the motor teminal so no problem there. the few motors that i do have, that spin CCW are the only ones that the axle gear has to be reversed, so the advance in timing works right.. the majority of slower cars have neutral timing and no red spot, so there okay as long as the motor leads propel it the right way down the track. i think ive got it all sussed out now thanks to your help. by the way i,ve got that chinese dimmer switch and the DPDT switches in and it all works a treat. i was racing the grandson all afternoon on very low voltage and he beat me loads[he,s 3 yrs old] its his first question coming through the door, are we going to race our cars today. so i must be doing some thing right. he has the magnet cars and i run without, to even it up a bit. john