+/- terminals on Kato GG1 motor

[bbussey]

Stupid question time.  I'm utilizing the Kato GG1 motor for my scratchbuilt EP3, but not any of the GG1 prefab controllers.  How do I determine the polarity of the motor terminals — i.e., which one is the positive terminal and which one is the negative terminal?  Pic of the motor is attached, in the proper orientation with the front facing right and the blue magnet facing up and the white magnet facing down.

[victor miranda]

I install it and then when I get it wrong I flip the motor...

 
never tried to get it right from the start.

In most Kato locos the white paint is on the top and it usually goes to the right wide...

Since the gearing determines the direction, I suspect
the motor design is meant to be installed in either direction.

victor

[peteski]

What Victor said.  The permanent-magnet DC motors used in model trains are bi-directional (you know that). 

Yes, there is a convention where some motors do have their lead polarity marked on them.  I think that is so if you apply the voltage according to the polarity markings the motor will run clockwise (looking from the front).  Or maybe the other way around.  But most model train motors do not have those markings,.  Often one of the magnets on open-frame motors is marked (which serves the same purpose as marking the electric terminals.

I usually do not pay much attention to this since rotating the motor 180 degrees will make it run in reverse - that flips the polarity of the voltage applied to it. Of course leaving the motor mounted and just reversing the leads will do the same.

[bbussey]

Okay, then I guess it's trial and error.  The GG1 motor frame clips only allow it to be installed with the white-faced magnet down.

[bbussey]

I went to the Digitrax site and looked up the specs for their decoders.  Don't know why I didn't think to do that first.  Motor(-) is the contact that was connected to the left (fireman) side pickup, motor(+) is the contact that was connected to the right (engineer) side pickup.  Gray wire to motor(-), orange wire to motor(+).

[peteski]

I went to the Digitrax site and looked up the specs for their decoders.  Don't know why I didn't think to do that first.  Motor(-) is the contact that was connected to the left (fireman) side pickup, motor(+) is the contact that was connected to the right (engineer) side pickup.  Gray wire to motor(-), orange wire to motor(+).

Ah, so the question was about hooking up the DCC decoder to the track lead.  While what you describe is the standard convention,it is really irrelevant.  The important thing is to properly hook up the motor.

The loco will run on the correct direction (as indicated on the DCC throttle) if the motor is wired correctly.  If the loco was originally DC then the orange motor output lead  attaches to  the motor terminal which was originally attached to  the right side track pickup (DCC red wire) and the gray motor output lead  attaches to  the motor terminal which was originally attached to  the right side track pickup (DCC black wire) .  once the loco's motor is wired correctly, swapping the track power leads will have no negative effect.

It is easy to remember the colors: Red is right and red goes with orange and black goes with gray (as color similarity goes).

[mmyers]

You need to determine which way the motor will need to rotate to go forward when installed. Whichever pole is + to do that and you have it. Switch direction on the direction switch and the polarity will change as will will rotation. Main thing is if a decoder is being installed, the orange wire goes on the positive terminal when the motor is driving the engine forward. Get that and all the other directional stuff on the decoder will also work.

martin Myers

[peteski]

You need to determine which way the motor will need to rotate to go forward when installed. Whichever pole is + to do that and you have it. Switch direction on the direction switch and the polarity will change as will will rotation. Main thing is if a decoder is being installed, the orange wire goes on the positive terminal when the motor is driving the engine forward. Get that and all the other directional stuff on the decoder will also work.

martin Myers

Ah, a much more concise explanation of what I was trying to say - nice!