08-09-11, 08:35 AM | #11 |
Lex Parsimoniae
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My guess is lower RPMs likely means more current, which could lead to a hot motor..
I wonder if a current sensor could be used to control AC power input to a motor?? http://ecorenovator.org/forum/applia...r-limiter.html Something like this circuit breaker, working at high speeds? Once the motor got running it's max RPMs/load could limited by the amount of current you allow it to draw.. RPMs would coast down between power cut-offs..?. If a loaded motor normally uses 8A, but you limit it to 5A, it's bound to run a bit slower..?. |
08-09-11, 11:44 AM | #12 | |
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Quote:
Here is an excellent explanation of how they work. Understanding how induction motors actually work will help in giving useful advice. -AC_Hacker
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08-09-11, 01:21 PM | #13 |
Lex Parsimoniae
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Luckily, I wasn't giving advice, but asking questions.
Wondering if some missing 60hz cycles would cause the motor coast down a bit.. It seems like the motor would be trying to speed up and then slow down, as the power disappeared, and then reappeared at the next Zero crossing.. To test the idea, I would need to build another control circuit, like this one. But without the second SSR, since I would only be switching the hot side. I would also change C1 to a much smaller value, for faster switching. I'm wondering if the flywheel effect would come into play.?. Maybe there is a low current setting that would allow my mill-drill to run without the RPMs zooming up and down too much..?. What do you think? Is it a waste of time to try it? |
08-11-11, 09:12 AM | #14 | |
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Quote:
-AC
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08-11-11, 12:26 PM | #15 |
Lex Parsimoniae
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I have been really busy on other things (getting ready for winter),
so building another power limiting rig is on a back-burner right now. Once I get it built and tested, I'll know if it makes the RPMs surge, and post my findings. |
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