Pete the Elaner Posted October 4, 2016 Share Posted October 4, 2016 I am thinking of using some poorer runners for double-heading (specifically Lima 31s). I am planning to remove some gears to allow them to run freely & maybe re-wheel them too. I am considering keeping DCC for lights & sound & would prefer to keep the ability to read CVs if possible.. I have JMRI so adjusting CVs by name rather than number should not be a problem. It is possible to disable the motor by adjusting a few CVs? Link to post Share on other sites More sharing options...
Nigelcliffe Posted October 4, 2016 Share Posted October 4, 2016 You could try setting the three-point speed curve to effectively zero (or nearly zero) for all three points (min, mid and max). That should stop the motor turning much. Or, you could just disconnect the motor lead ! - Nigel Link to post Share on other sites More sharing options...
tamperman36 Posted October 4, 2016 Share Posted October 4, 2016 you could remove the gears from the motor thus allowing the wheels to rotate freely, but you could possibly use the motor drive wires to fit a working roof fan Link to post Share on other sites More sharing options...
Pete the Elaner Posted October 4, 2016 Author Share Posted October 4, 2016 You could try setting the three-point speed curve to effectively zero (or nearly zero) for all three points (min, mid and max). That should stop the motor turning much. Or, you could just disconnect the motor lead ! - Nigel Disconnecting the motor would certainly stop it from working but it would also stop the system from reading CVs, which was what I was trying to avoid. I wondered just how much control the variables had on motor control & thought the answer may lie on this path. Link to post Share on other sites More sharing options...
Pete the Elaner Posted October 4, 2016 Author Share Posted October 4, 2016 you could remove the gears from the motor thus allowing the wheels to rotate freely, but you could possibly use the motor drive wires to fit a working roof fan Some of the gear wheels have already been removed. I had not thought of driving a roof fan. That would add to the project creep. Link to post Share on other sites More sharing options...
SRman Posted October 4, 2016 Share Posted October 4, 2016 Disconnecting the motor would certainly stop it from working but it would also stop the system from reading CVs, which was what I was trying to avoid. I wondered just how much control the variables had on motor control & thought the answer may lie on this path. I agree with Nigel (post #2): setting a very low value in CV 5 and 6 should do the trick. It may also help to set CV2 = 0, as Lima motors often need a little more kick to get going (this will remove that extra starting "oomph"). I have once stopped a motor from responding by accidentally setting ridiculous values in CVs 5 and 6 but I can't remember what I did at the time. I'm not sure what would happen if you set them both to zero; either that would completely stop the motor from responding, or it will go to the decoder defaults and run 'normally'. Link to post Share on other sites More sharing options...
RMweb Premium Steven B Posted October 5, 2016 RMweb Premium Share Posted October 5, 2016 If you want to maintain the ability to read back CVs then could you replace the motor with a resistor? (and set the speed curve to 0 so as not to waste track power). Happy modelling. Steven B. Link to post Share on other sites More sharing options...
dasatcopthorne Posted October 6, 2016 Share Posted October 6, 2016 Remove the gears, otherwise you will be trying to drag a non-working motor. You need the motor in-circuit to get responses from the chip. Dave. Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted October 6, 2016 RMweb Premium Share Posted October 6, 2016 As the bearings of a loco are not running as free as a coach be careful - halve of the pulling power of your " double header" will be used for pulling the modified loco... Why not considering a real programmed double header? Even if the loco is not such a good runner the other one should help it to get over this contact problems... Link to post Share on other sites More sharing options...
34theletterbetweenB&D Posted October 6, 2016 Share Posted October 6, 2016 Alternative approach, remove the weight and traction tyres (rewheel) and you will have a loco which can move itself independently - if that ls ever a potential part of your operation - but will have no effect in multiple coupled to a heavy centre motor type. Pick up is best maintained on driven wheels, so there is an advantage in reliable current supply to the decoder. Link to post Share on other sites More sharing options...
Pete the Elaner Posted October 12, 2016 Author Share Posted October 12, 2016 Thanks for the replies. I have tried changing all the speed variables I can find... but the motor still spins. The gears are sitting on the workbench so the loco is able to move (fairly) freely. One of the uses I wanted it for was to top & tail engineer's trains so I can't have the rear loco powered because I know it will either snatch or drag, in either case causing a derailment. To make matters worse, my stock is coupled with screw links & instanters. I found that with the motor settings set to zero, the motor still turns but I can't rev the engine up with the throttle. It seems that Legomanbiffo has now created a solution which solves this: his "Drivelock" function. Link to post Share on other sites More sharing options...
RMweb Gold Dagworth Posted October 12, 2016 RMweb Gold Share Posted October 12, 2016 Set CV 19 to 99* As long as you never try to use advanced consist number 99 then the motor of that loco will never do anything. The lights will still respond to the normal decoder address To put the loco back to normal operation again set CV19 to zero and put the gears back. Andi *99 used as an example, could be any two digit number but NOT 03! Link to post Share on other sites More sharing options...
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