3 Pin Motor Block

JimmyB

JimmyB

Phase 1 complete, roll on Phase 2
23 Feb 2018
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I am sure I have seen a thread on this, but I cannot find it, basically have to convert a 3 pin motor block to a 4 pin block. Having stripped down a motor block I can see what the issue is, i.e. one side pick up passes through the motor connection with no separation, is there an easy(ish) fix :)
 
JimmyB

JimmyB

Phase 1 complete, roll on Phase 2
23 Feb 2018
1,866
275
65
Weston-super-Mare
Zerogee

Zerogee

Clencher's Bogleman
25 Oct 2009
16,794
189
North Essex
That guide is useful, but doesn't seem to mention putting a short piece of heatshrink over the "white" terminal pin, and also over the new yellow wire and the motor tab it is soldered to, in order to ensure that they are fully isolated from each other. When bending the motor terminal tab away from the white pin, you can either bend it inwards or outwards, but if you go outwards (leading the new yellow wire outside the white pin) then you may need to carve a little bit of plastic away from the inside of the gearbox sidewall to make sufficient clearance for the wire. Taking the yellow wire inside the white pin can be easier provided you ensure that the new wire cannot foul the motor shaft or worm. Provided you've insulated everything with heatshrink, you won't have to worry about the physical proximity of the pin and wire.

Jon.
 
Ralphmp

Ralphmp

Registered
6 Jan 2010
880
37
Herts
I vaguely remember a posting from way back where the person doing the conversion had used a piece of copper wire from one of the live or ground wires in (I think) 45amp twin and earth cable to attach to the motor terminal instead of a flying lead. This meant that when re-assembled, the motor block had, in effect, 4 pins to connect to as opposed to 3 pins and 1 piece of cable. I've not done a 3 to 4 pin conversion since the post was issued (all mine followed Mike D's step by step guide on GSM) so I can't speak to the effectiveness of the "4th pin" approach. However, it did seem a neat alternative when fitting a DCC decoder.
 
LGB333

LGB333

Active Member
I just converted an LGB 2156 Santa Fe Alco Diesel to DCC using a Massoth XLS power/sound decoder. The LGB 2156 has two, three pin motor blocks and I found just clipping off about 1/8th inch from the motor's right side copper connector did the trick. Didn't have to mess with either binding the connector or the holding area of the motor's pin........the 1/8th inch provided sufficient physical separation from the existing "white" track power pickup pin. Then I soldered the "yellow" wire to the outer side of that motor connector.......plenty of space to hold the solder and the wire.

I've found several challenges when I've tried to modify the plastic base around the shared "white" pin to isolate the motor's copper connector, same with trying to bend the motor connector, it usually causes the motor to not seat into the motor block properly, i.e., to extend up higher than it should. This is usually found when I try to screw the motor block's cover back on. And then additional trial and error adjustments. Anyway, just my experience with these motor block modifications........so just cutting the motor connector to a shorter length certainly did the trick for the LGB 2156 loco.
 
Greg Elmassian

Greg Elmassian

Registered
8 Mar 2014
2,902
188
San Diego
www.elmassian.com
I found that I was able to isolate the motor from the track by putting a length of heat shrink on the long rod (sorry I did not take pictures), the advantage being that I could remove the heat shrink later and restore it to a 3 wire block easily.

Greg
 
JimmyB

JimmyB

Phase 1 complete, roll on Phase 2
23 Feb 2018
1,866
275
65
Weston-super-Mare
I have not gotten around to converting mine yet, but I will try to document the work carried out.