Glad we now have a definitive decision. The motor expert has spoken.BUT really, the whole idea and concept seems like a poor choice.
Glad we now have a definitive decision. The motor expert has spoken.BUT really, the whole idea and concept seems like a poor choice.
Consider that the TS is proposing the use of a stalled motor in place of a spring. Then explain how that makes sense. It will be interesting to see what you come up with.Glad we now have a definitive decision. The motor expert has spoken.
I read the whole thread again and I find nothing stated by the TS to imply anything else than the motor is used to rewind a string winch after a package is pulled out. There may be a possibility that the motor gets switched on to do the retract, but I did not see that mentioned. Certainly a system that gets switched on and otherwise is allowed to turn freely is reasonable, but at that point there is the question of what switches it on and off.@MisterBill2 Back to not taking time to read the whole thread are we?
Did you happen to see this?Consider that the TS is proposing the use of a stalled motor in place of a spring.
I am designing a sort of winch system, where the user can pull the package freely, and once they are done, the winch reels back up the string around a drum. I would like to use a DC motor connected to the drum to reel back the string. This means that when the user is pulling the winch, the drum will spin in one direction (let's say clockwise), but when the motor is reeling back the string, the drum will rotate in the opposite direction (anti-clockwise). This also means that the motor - which is not engaged in the first part - will be forcefully spun clockwise, and then it will kick in and spin anti-clockwise afterwards.
Yes, it will act as a generator. Why does this worry you?I am worried that when we are forcefully spinning the motor in the clockwise direction, it will act as a generator.
I would say it means that you are presenting a voltage at the output of your system. If your system is poorly designed, then maybe it will allow some current into it's circuitry.This means we are sending current back into the system
What are these electronics? What is this "system?" Is it a DC motor drive? If so, it should have no problem with back EMF. If it's something that you've designed, maybe design it to handle this.- possibly damaging electronics. How do I overcome this?
That effect is primarily with permanent magnet DC motors. Wound field motors tend to have much less cog effect when turned with the power off.A DC motor with permanent magnets produces magnetic "cogging" when it is disconnected and is spinned.
Maybe a very little one from a standard PMDC motor that most would never notice. But a BLDC motor is a different situation, it does have a real "cog" feeling to it. This is due to the poles salient poles of a BLDC verses the distributed poles of a PMDC motor.A DC motor with permanent magnets produces magnetic "cogging" when it is disconnected and is spinned.
I just did a check and our TS claims to be an electrical engineer. Perhaps the definition has changed a bit, maybe.Maybe a very little one from a standard PMDC motor that most would never notice. But a BLDC motor is a different situation, it does have a real "cog" feeling to it. This is due to the poles salient poles of a BLDC verses the distributed poles of a PMDC motor.
Is that important to you?I just did a check and our TS claims to be an electrical engineer.
I'd say yes, since mrbill claims the same thing.Is that important to you?
Max, YES! if an individual claims an educational background then I do not need to be concerned about confusing them when I reply, while if they are a new-be, then I need to provide a much more detailed explanation. Also, if an individual claims to possess a specific skill set then why do they ask such uninformed questions???Is that important to you?
Odd that the OP has not come back, in spite of 22+ posts?
Max.
I thought that's what the forum was for.There are too many NOOBS on these electronics forums.
I never said or implied that I was down on Noobs. I am always willing to share knowledge and insight with those wanting to learn. And a long career has given me a lot of experience beyond what I learned in college.There are too many NOOBS on these electronics forums.
Agreed. Here we can discuss the basics.I thought that's what the forum was for.
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