On Friday, February 06, 2015 12:11:45 PM Viesturs Lācis wrote: > Not sure, what do you mean. > I need torque limiter to protect the worm gearbox in case of power > failure, when it is rotating 2 ton platform, VFD would handle > acceleration/deceleration during normal operation. > > Thank you, guys, for the links, already sent few enquiries, hopefully > there will be some useful replies. > > Viesturs
Don't forget that in a worm drive, the drive is not normally reversible. IOW the worm, driven by the motor, and moving the table/plsatform, but if the motor stops from a power failure, it is up to the bull gear to have strong enough teeth to stop the platform in its tracks. A torque limitor between the bull gear and the 2 ton platform would need to have a pretty high limit, but not so high as to clear a few teeth off the bullgear or worm or both. How big are the gears, and how well anchored is the worm housing? AIUI, the harmonic drive is not as irreversable as the worm drive, but for something that heavy, it would be quite a bit larger/heavier/costly in comparison to the worm drive. Might it be possible to make a coupling using valve springs as the give element, in the same manner as the hub of an auto/truck clutch disk but on a 5x size scale? Something that would, if the drive freezes, allow the platform a few degrees of rotation to get stopped and bounce backwards to a resting point when the worm stops dead suddenly? The give of the valve springs would broaden the applied torque pulse enogh to save the gears. I'd be quite amazed if someone actually builds a slip clutch on that sort of a scale where the thing might have 2+ tons to stop. I would expect to have to make it. Perhaps one could mount a small auto flywheel and clutch assembly on the bullgear output shaft, and drive the platform from the input shaft of the transmission that fits the disk by milling off the rear of the tramnsmission, and using the bell housing to hold & maintain the shafts proper alignment under power? Just let the clutch disk slip a few degrees to act as the torque limiter you need. Interesting bit of "what if"... It might be interesting to visit the scrap yard with your imagination working. > 2015-02-06 18:57 GMT+02:00 Nicklas Karlsson <[email protected]>: > > There is a strong correlation between torque and current in an Electric > > motor. For DC motors and servo motors it should be relatively simple to > > implement but I do not Think there is any simple solution to Control > > current in an ordinary cheap induction motor. > > > > Nicklas Karlsson > > > >> Hello! > >> > >> I would appreciate, if somebody could suggest European > >> manufacturer/reseller for reasonably priced friction torque limiters. > >> I mean someting like this: > >> http://www.nuteckcouplings.com/torque-limiters.html > >> > >> The goal is to limit the max torque between sprocket and shaft to 100 > >> Nm. I have tried contacting some italian manufacturers, but they do > >> not seem to care to respond. I got an offer from a german > >> manufacturer, but that seems too pricey, so I would like to find some > >> other alternatives as well. > >> > >> Viesturs > >> > >> ---------------------------------------------------------------------- > >> -------- Dive into the World of Parallel Programming. The Go Parallel > >> Website, sponsored by Intel and developed in partnership with > >> Slashdot Media, is your > >> hub for all things parallel software development, from weekly thought > >> leadership blogs to news, videos, case studies, tutorials and more. > >> Take a look and join the conversation now. > >> http://goparallel.sourceforge.net/ > >> _______________________________________________ > >> Emc-users mailing list > >> [email protected] > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ----------------------------------------------------------------------- > > ------- Dive into the World of Parallel Programming. The Go Parallel > > Website, sponsored by Intel and developed in partnership with Slashdot > > Media, is your hub for all things parallel software development, from > > weekly thought leadership blogs to news, videos, case studies, > > tutorials and more. Take a look and join the conversation now. > > http://goparallel.sourceforge.net/ > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------- > ----- Dive into the World of Parallel Programming. The Go Parallel > Website, sponsored by Intel and developed in partnership with Slashdot > Media, is your hub for all things parallel software development, from > weekly thought leadership blogs to news, videos, case studies, tutorials > and more. 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