Isolating Motor?

[n1vets333]

 When they say to isolate the motor before connecting a decoder, do they mean to isolate the motors electric contacts from the wheels pickups or do they mean to isolate the entire motor from touching anything that conducts electric from the wheels? What will happen if this is not done corrctly?

[jeffrey-wimberly]

On some locos, especially the Athearn Blue Box locos, the motor grounds to the frame. To work with DCC the motor can't be allowed to ground to the frame or the decoder will be fried. On the Athearn's it's an easy fix. Remove the motor from the loco, break the grounding prongs off the bottom of the motor, place a strip of electrical tape in the motor well, solder a wire to the bottom  of the motor and put the motor back into the motor well. The wire you soldered to the bottom of the motor will connect to the gray wire on the decoder.

 

[SpaceMouse]

The short answer is that it is the poles that have to be isoated from the frame/ wheels.

[n1vets333]

by poles you mean the red and black wire contacts?

[Vail and Southwestern RR]

by poles you mean the red and black wire contacts?

By poles he means the actual electical contacts to the motor.  In some cases, these contacts are made through the frame, in some cases by wires.

[SpaceMouse]

by poles you mean the red and black wire contacts?

Basically you are right, but actually the pole is where the red and black wires connect to the motor and the consquence of wiriing it wrong is you let the smoke out of the decoder. The simple thing to do is to touch the pole with one end of your multi-meter to the and the other to the wheels, set to test continuitiy and if it doesn't beep you're good to go. If it does beep you have to separate the pole from the frame somehow. This could be as easy as detaching a wire or as tough as moving the motor off the frame and connecting it with nylon screws.

The consequence of not isolating the poles is that the decoder will give up its smoke.

Decoders won't run unless you keep the smoke in them.  

[n1vets333]

I have tried installing mrc decoders in about 4 different engines, all of which were quit old and have had no luck. Even though the decoder didnt start smoking, the engines didnt move, any idea what im doing wrong? Could the engines just not be compatible due to their age? Do decoders work with any type of ho motor?

[jeffrey-wimberly]

I have tried installing mrc decoders in about 4 different engines, all of which were quit old and have had no luck. Even though the decoder didnt start smoking, the engines didnt move, any idea what im doing wrong? Could the engines just not be compatible due to their age? Do decoders work with any type of ho motor?

If the motor pulls more power than the decoder can deliver, one of two things will happen. Either the decoder will be damaged or, if you're lucky, it'll shut down.

[n1vets333]

HOW DO i KNOW WHICH IS HAPPENING, LIKE i SAID THE DECODER DIDNT SMOKE IT JUST DIDNT MOVE OR LIGHTS TURN ON?

[jeffrey-wimberly]

Did the locos run well on DC? Do they run on DC now?