I have seen advice that it is not best to cycle a larger dust collector on and off too frequently. Why is this the case for DC’s and not other power tools ie. table saws, lathes, bandsaws etc?
Printable View
I have seen advice that it is not best to cycle a larger dust collector on and off too frequently. Why is this the case for DC’s and not other power tools ie. table saws, lathes, bandsaws etc?
Applies to all motors except, compressor duty motors. Dust collectors take the longest time to ramp up to speed so the starting coil is no longer energized and dumping heat into the motor. A table saw has almost no starting load.
A dc is the only motor in the shop that is running at full load 100% of the time, it never idles at a low power draw. A stick welder is so low an on time that the NEC allows you to use undersize wire from the breaker to the welder outlet. 40 amp wire from a 50 amp breaker is code.
Bill D
Bill has the rationale, at least for industrial-sized dust collectors. For one-person shops, perhaps the story is different. The motors are typically 2 or 3 horsepower, not 20 or 50. They get up to speed in a couple seconds. These smaller motors do get a pulse of heat at start-up, but it just isn't that big. For instance, my dust collector has a 2 1/2 horse motor. I turn it on when there's stuff to collect, and turn it off when there's not. On a busy day at the shop, it may go on and off a couple dozen times. The motor does have an over-temperature cutout, which has only tripped in a brownout. It is now 18 years old, and has been used nearly every day. It is still going strong.
What is your idea of "larger dust collector"? 5hp or 20hp? Hobby shop or commercial? Number of machines running at one time? 0 or 6?
Thank you for the clarification request. I should have been more clear. 3-5 HP range.Quote:
Originally Posted by Richard Coers
Is the problem that the starting capacitor will wear out too quickly because of overheating due to too frequent use, or is there also some sort of damage done to the motor itself?
Starter winding may overheat and burn insulation.
Bill D
If it helps, I recently asked Oneida how often I can safely cycle a V-3000 3 hp unit. They said no more than 6 times an hour.
Cliff
Use a 3 phase motor and a VFD and there is no limit on starts per hour, this is how Clearvues are controlled in Australia.
I'm one of the unfortunate to learn the hard way. Clearvue 1ph 5hp with a Leeson motor started on fire. They reckon the capacitors overheated, leaked oil into the windings, and caught fire. Their rationale for it is too many starts without giving the motor time to cool down inbetween. They recommend no more than 3-4 cycles an hour. D.C.'s are much harder starting than other tools, especially if blast gates are left open when starting, and they don't cool down as quickly as other machines.
I wonder how many other CV owners have had this problem, I still can't understand why CV, Oneida etc still supply single phase dust extractors for the bigger models and I guess it is a hangover from when VFD's were not as widely used or as affordable as they are. Are you going to replace it with another single phase motor?Quote:
Originally Posted by Jonathan Jung