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point moters for code 75

879 Views 3 Replies 4 Participants Last post by  billericaybill
Can someone help me out with this one , i have mounted two point moters on to my code 75 3 way point and had to fit on to them a pl13 SPDT switches
The point moters throw the point across ok ,but the two SPDT switches dont seem to go all the way across and will not change the polarity. I have to give them a little push with my finger to make them go all the way over before i can get them to work,as they are mounted on to the bottom of the point with the pin into them i do not see why they will not work.

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***Yes, they should work. Like many things built with sloppy tolerances however ...sometimes they simply don't which is frustrating. This is largely due to internal friction and loose tolerances combining to make the throw "only just" happen... this is contributed to by the fact that the switch added to the point motor means a lot of friction unless the power supply is really adequate this sort of thing is always likely.

Try lubricating both the point motor and the switch with a little plain old vaseline (not oil!). It may just free things very slightly, perhaps enough to give them that extra wee bit of throw.

Sounds to me like your point motors are not properly centred. The throw of the PL10 point motor is much greater than that required to move the blades. You can have the situation where the blades move back and forth OK, but the off-set motor leaves the PL13 contacts in mid-position on one path. I've had this problem several times and have had to carefully adjust the position of the motor. I assume you are using PL12 mountings rather than direct attach.

One way of overcoming this is to first fix the blades of the points in mid-position using a bit of blue-tack between the blades and stock rail. Then fix the point motor so that the operating pin is also in mid-position. That should ensure proper centering of the motor and hence the switch.
another way to centre the point blades is to push a matchstick between the moving rail and the side rail on both sides. that way it is possible to adjust the blades so they are exactly centred and locked in. Another way to got more throw, admittedly ugly but very effective is to elongate the hole in the tie bar so that the motor bar has more room to throw. i have used this on seep motors when they have not had sufficient side to side movemen to switch contacts on code 75 finer scale points.
regards, Andrew
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