Spindle speed stuck need new pots????
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  1. #1
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    Default Spindle speed stuck need new pots????

    Tonight while running my lathe I set the spindle lock then I forgot to disengage the lock before turning the spindle back on, no problem the lock switch worked and the lathe shut off. After I disengaged the lock and restarted the spindle, the rpm would not adjust. Everything else seemed ok, and there were no strange noises. I started disassembling and found a broken post on one of the AB 33173 pots. I'm hopeful this is my only problem but I'm having a difficult time finding a replacement pot.

    What are my options for a new speed controller pot?

    Thanks!

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    What model and year lathe is this for?

    Cal

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    Oops, it is a 1962 10ee

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    I would suggest attempting to solder to the remaining post. The pots were custom manufactured with the armature and field pot having their windings shorted over half of the travel and different on both. Monarch might have a used one, or you might find one on eBay or the like but if you can solder to the remaining post I'd go that route to start.

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    Not for a 62. It looks like a common dual piggyback clarostat type, but unfortunately way, way special.

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    Default Question about the 10k and 50k Pots for speed control on modular

    The schematic shows 10k and 50k, but is that before having half of the rotation shorted or after? A 1968 modular I acquired is missing these pots being discussed in this thread.

    Bob

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    That would fit my 1941 MG, it's a dual rheostat. My field rheostat isn't working.

    Sent from my SM-G950U1 using Tapatalk

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    At this point my plan is to find another 10K pot and replace the innards with my dual pot set up. Has anybody had any success in Frankensteining two pots together?



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    The problem is that the pots are custom for Monarch - for half of their travel the windings are shorted, other half work as normal, and the halves are reversed between the pots. This is so the armature voltage increases and the field remains high for the first half of the travel and the field decreases while the armature remains high for the second half You can't replace any part involving the windings with standard pots.

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    You can use separate pots, making speed control a two step operation or use pots with twice the resistance and use zener clamps to limit the voltage.

    Bill

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    So I replaced the potentiometer with a new used 10ee pot I got from a member here and I now have an issue of the spindle not having any control at low rpm and then shutting off around 2400rpm. I can restart the lathe by re pressing the green start button but not sure where to go from here. I have made a video showing the issue.

    YouTube

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    The field tube could be your problem, anyway its good to have a known to be good spare. The same with diodes.


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