3 Pin Motor Block

JimmyB

JimmyB

Phase 1 complete, roll on Phase 2
23 Feb 2018
1,486
139
65
Weston-super-Mare
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
1,486
139
65
Weston-super-Mare
Zerogee

Zerogee

Clencher's Bogleman
25 Oct 2009
16,514
61
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
750
0
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.