Isolating a motor

[Aussie 3 railer]

Hello all again.

Busy day here today lots of questions. I keep reading where the motor needs to be isolated or insulated. Bit confused here and probably miss understanding the term. Can someone enlighten me please.

Dirk

[Rog (RJ)]

All it means is that the motor's electrical connections must be isolated so that there can be no contact with the chassis (if it's live) or the connections to the pickups or rails. Any electrical connection will destroy the decoder.

Ringfield motors often have the left hand brush connected to the chassis and this connection must be removed.

[Mountain Goat]

The need to isolate motor connections is if one needs to hard wire a DCC decoder in the locomotive. If one runs on ordinary 12v DC, one does not need to worry about it. Is only the DCC'ers need worry about motor isolation.

[Aussie 3 railer]

Bit confusing here. The motor is mounted, screwed to the chassis. The output shaft is in contact with the worm and wheel which is in contact with the chassis. I understand the motor wiring (2 wires) is connected directly to the decoder.

Dirk

[Brian]

If there is any connection between the decoders output wires (Orange and Grey) that go directly to the motor, upon placing the loco onto DCC powered rails it will immediately cause the decoder to fail. Usually terminally! Hence the need to test both motor connections once the old DC wiring has been removed from the motor, testing each motor tab to the wheels and where necessary any metal mount / chassis. Any test showing a connection MUST be corrected to remove the connection before proceeding with the rest of the decoder installation.

There must never be any track power connection to the decoders output.

Equally you should never apply an external DC voltage directly to the motor with the decoder still connected to the motor. If a DC power is applied with the decoder still connected to the motor the decoder will terminally fail usually in a puff of smoke!

[RAF96]

Given your username, by chance are you trying to convert 3-rail locos to DCC.

[Aussie 3 railer]

Hello RAF, no I've given the 3 rail system away after I caught this DCC diaease. Since then is been a very sharp learning experience and I am indetted to so many people here for the guidance. I am living it daily now and loving it.

Dirk

[Aussie 3 railer]

Many thanks Brian and to everyone else who helped. I am with it nowat last..

Dirk