About this isolating thingy

[SpaceMouse]

QUOTE: Originally posted by JohnT14808

Chip...saw your follow up post with photos...Great work!! Hope mine goes as easy....I think I'll try it on an older switcher first......

I think with the more recent stuff, easier happens more often than harder. In my short experieince, harder means getting a decoder into the space, not making the electrioncis work.

[JohnT14808]

Chip...saw your follow up post with photos...Great work!! Hope mine goes as easy....I think I'll try it on an older switcher first......

[SpaceMouse]

Thanks Randy. Good tip.

[rrinker]

See the disagreement here comes because BOTH people. It really doesn't matter HOW you isolate the motor, just that it IS isolated.

If one of the brushes is connected to the motor case, and then to the chassis - you can isolate the brush from the motor case, OR you can leave that aloneand isolate the motor from the chassis. Or both, if you are really paranoid, but one or the other will work just fine. Just as long as there is NO PATH from the loco chassis to the motor brushes - in other words, no way to bypass the decoder. You have power on the right hand rail that gets to the motor. The decoder most be in the middle of this path, with no way around it. You have power ont he left rail, that gets to the motor somehow. Again, the decoder must be in the middle of this, with no way around it.
You can usually eyeball it. A meter can help, just to be sure.

Chip - remember the Proto2000 S1, with the new orange wire? That's a good example of what needs to be done, although the only danger there is because at the extreme swivelled position, a wheel could contact both the track and the metal frame of the loco. Had Life Like pulled an Athearn and used the frame as the electrical path right from the wheel, you'd have an real isolation issue, but the procedure to connect up the orange wire to the lower motor brush would resolve it.

Always, ALWAYS put a newly decodered loco on the programming track FIRST. The programming track is current limited - in other words that full booster power is not and can not be applied to the programming track. A few milliamps on the programming track will more than likely not damage a decoder. If it doesn't respond to program commands, DON'T put it on the main until you figure out the wiring fault. If you always remember that, you will probably never blow a decoder.

--Randy

[SpaceMouse]

QUOTE: Originally posted by JohnT14808

I'm with selector, Chip....Pics and some comments please...and more pics!! Then of course is the movie rendition of "...When She's Comin' round the Mountain...." so we can all see your DCC loco in action!!!

I will but it looks like it might be pretty dull. I pulled the cover off just now to soak it just now and both motor poles are on the top. One goes to the wheels, the other to the motor case and screws down. Isolating this sucker is probably going to be as easy as disconnecting that lead to the motor case.

[JohnT14808]

I'm with selector, Chip....Pics and some comments please...and more pics!! Then of course is the movie rendition of "...When She's Comin' round the Mountain...." so we can all see your DCC loco in action!!!

[SpaceMouse]

QUOTE: Originally posted by SpaceMouse

Would touching the leads to the poles and to each side wheels be a reasonable test?

QUOTE: So always check that neither motor lead is connected to your locomotive's frame. Do this by connecting an ohm meter between either motor lead and try every wheel. Then do the other motor lead and all the wheels. Note: The motor frame in all likelihoodis connected to your frame. This isn't a problem. It's the leads to the motor, the ones you will soon attach decoder wires to, that are your concern."

I seem to have gotten it. Thanks everyone.

[Anonymous]

Remember the electronics rule "All electronics runs on smoke! When the smoke escapes, the eletronics don't run any more"!! It may be a steam locomotive, but that only the toys are supposed to have the smoke makers.
Will
P.S. Check the decoder to motor side of the connections for continuity to the frame. The warrantee on the decoder does not cove escaped smoke!!

[Anonymous]

This is straight off Allan Gartner's web site.

"RECOMMENDATION 8-8: ALWAYS Ensure That Neither Motor Lead is Grounded to Your Locomotive's Frame

That's right. Don't trust me. If I say that the motor in a particular locomotive is not grounded to the frame, don't believe me. Who knows for sure that the motor that came with your locomotive is the same as the one in mine. If you have a different motor, your decoder could be destroyed. So always check that neither motor lead is connected to your locomotive's frame. Do this by connecting an ohm meter between either motor lead and try every wheel. Then do the other motor lead and all the wheels. Note: The motor frame in all likelihoodis connected to your frame. This isn't a problem. It's the leads to the motor, the ones you will soon attach decoder wires to, that are your concern."

[Anonymous]

That's incorrect. All you need to do is isolate both motor connections from the frame. That's ALL. As long as there's no electrical continuity between the motor brushes, and the frame of the loco, you're good to go.

QUOTE: Originally posted by cacole

Touch one lead to the frame and the other to both brushes, one at a time. If you get a tone or Ohm reading of anything but Infinity, the motor is not properly isolated from the frame. Just putting electrical tape between the motor and frame is not enough -- you must also change the machine bolt that holds the motor from a metal to a nylon one; or use double-sided white foam tape to secure the motor if it is flat enough for the tape to keep the motor from moving under load.

[Anonymous]

It doesn't have anything to do with the motor itself, but rather the motor contacts. If the frame is connected to one of the contacts (brushes) then it has to be isolated. I have an old AHM 0 4 0 that had one side of the motor (brush) grounded to the frame. I defeated the connector, and converted it to DCC. It's been running over a year. The motor is still mounted to the frame. You don't have to isolate the motor itself, just the motor connections. Now I know on some older ones sometimes that's hard to do, because there is only one connection on the motor, and the frame makes the other connection. In cases like that, you usually have to end up repowering.

QUOTE: Originally posted by jfugate

Chip:

You won't need a meter to find out.

The motor needs to be insulated from the metal frame and have two wires running to it.

If the motor contacts the metal frame anywhere, then you will need to remove the motor, put down some electrical tape, then mount the motor back in place with plastic screws.

Next you will need to find the two motor terminals and run the orange and gray wires from the decoder to each of the motor terminals.

Finally, you wlll need to connect the black decoder wire to one side of the track power pickup and the red wire to the other side. If you only see one wire inside the loco going to the motor, or you see one motor wire anchored to the frame with a screw, then the frame is being used to transmit power to one side of the motor.

If the frame's "hot", then you can connect either the red or black decoder wire to the frame, and the other wire to the wire(s) coming from the trucks. Also make sure the decoder does not touch the frame anywhere.

Does this make sense?

[selector]

Chip, if you are of a mind, especially since you are fairly confident in your skills and know-how, would you consider your own clinic with pix. It needn't be a multiple pager, unless you get lots of inquiries and discussion, but guys like me might benefit from a five or six photo essay and a few captions as you install the decoder and do all testing, including what you are doing now.

I, for one, would be highly grateful.

[SpaceMouse]

QUOTE: Originally posted by cacole

Touch one lead to the frame and the other to both brushes, one at a time. If you get a tone or Ohm reading of anything but Infinity, the motor is not properly isolated from the frame. Just putting electrical tape between the motor and frame is not enough -- you must also change the machine bolt that holds the motor from a metal to a nylon one; or use double-sided white foam tape to secure the motor if it is flat enough for the tape to keep the motor from moving under load.

Thanks. I have nylon screws.

[Anonymous]

But before you can test you have to remove the existing connection from the brushes to the wheels....it's obvious, but easy to forget!

[cacole]

Touch one lead to the frame and the other to both brushes, one at a time. If you get a tone or Ohm reading of anything but Infinity, the motor is not properly isolated from the frame. Just putting electrical tape between the motor and frame is not enough -- you must also change the machine bolt that holds the motor from a metal to a nylon one; or use double-sided white foam tape to secure the motor if it is flat enough for the tape to keep the motor from moving under load.

[SpaceMouse]

Would touching the leads to the poles and two each side wheels be a reasonable test?

[SpaceMouse]

QUOTE: Originally posted by jfugate

Chip:

You won't need a meter to find out.

The motor needs to be insulated from the metal frame and have two wires running to it.

If the motor contacts the metal frame anywhere, then you will need to remove the motor, put down some electrical tape, then mount the motor back in place with plastic screws.

Next you will need to find the two motor terminals and run the orange and gray wires from the decoder to each of the motor terminals.

Finally, you wlll need to connect the black decoder wire to one side of the track power pickup and the red wire to the other side. If you only see one wire inside the loco going to the motor, or you see one motor wire anchored to the frame with a screw, then the frame is being used to transmit power to one side of the motor.

If the frame's "hot", then you can connect either the red or black decoder wire to the frame, and the other wire to the wire(s) coming from the trucks. Also make sure the decoder does not touch the frame anywhere.

Does this make sense?

Totally. Thanks. I know how to wire it. I just was told over and over to test, test, test before I put it on the program track--especially with weird instalations. I just didn't know where to test, exactly.

[jfugate]

Chip:

You won't need a meter to find out.

The motor needs to be insulated from the metal frame and have two wires running to it.

If the motor contacts the metal frame anywhere, then you will need to remove the motor, put down some electrical tape, then mount the motor back in place with plastic screws.

Next you will need to find the two motor terminals and run the orange and gray wires from the decoder to each of the motor terminals.

Finally, you wlll need to connect the black decoder wire to one side of the track power pickup and the red wire to the other side. If you only see one wire inside the loco going to the motor, or you see one motor wire anchored to the frame with a screw, then the frame is being used to transmit power to one side of the motor.

If the frame's "hot", then you can connect either the red or black decoder wire to the frame, and the other wire to the wire(s) coming from the trucks. Also make sure the decoder does not touch the frame anywhere.

Does this make sense?

[SpaceMouse]

So if neither brush is contacting the frame, I'm good to go? BTW, I have plenty of electrical tape and nylon 2-56 screws.

On the MDC 4-6-0, I built, one brush was to be bent to contact the frame. So that might be a problem.

[jrbernier]

Chip - You need to isolate the 'motor brushes'. If you can place you ohm meter on the frame and get contact on either motor brush(or wire), you have a problem. Having not seen a MDC climax for years, I am not sure how the motor is grounded to the frame(if at all).
I know on the Athearn engines, the bottom motor contact is touching the frame with a small spring brass piece. Reforming(bending it) so it does not touch, soldering a wire to it and taping it will get you to DCC ready real fast!

Jim

[Anonymous]

Chip,
Some of this is conjuecture, but here we go:
Does the motor have two wires to it? If it only has one, the other side is coming from the frame, and you might be toasted (someone else may know a way around that).

With the meter set to some relatively small Ohms scale..
Between the two wires you should have a pretty small value.
Between either wire and the frame you'd like to see infinite Ohms.
Once the leads are disconnected from the wheels you'd like to see infinite Ohms from any wheel to either wire.

I think that should cover it, basically the trick is that the input to the decoder (wheels) tot the output of the decoder (motor leads) can't be touching.

The lights are another matter, and I have been confused there, so I'll let someone else jump in.

[SpaceMouse]

I understand that for a loco to run DCC without creating unwanted smoke, the motor cannot be in contact with anything that has power running through it.

So I've got the multi-meter one hand and a zillion year old MDC Climax in the other. Where do I put the pointy things to make sure nothing goes poof?