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Generally bad ideas.

eptheta

Dec 20, 2009
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Now I know very well that ratings exist for a reason, but...

How bad an idea is running a 12V rated motor using 18.5V ?
How long will it last before it burns out?

Assuming that it is a really bad idea, why ? Its only copper so it can take the current, and my fuse doesn't blow (but I ran it for about 4s) so its not because of low resistance related shorting....

This is probably the most incompetent question I have asked, but I desperately need faster motors.
 

TheLaw

Sep 27, 2010
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I wouldn't try it. You could probably undervolt it. But overvoltage is never good a good idea. Even if it works, it won't be reliable, most likely.
 

TheLaw

Sep 27, 2010
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Try an experiment on a cheap computer fan and run it at like 15V and see if anything happens.
 

Resqueline

Jul 31, 2009
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Well, it depends on what type of motor it is, how large safety margins it had to begin with, and what kind of duty cycle & load it'll be exposed to.
Kids "routinely" apply 12V to 3V toy motors, but I never tested myself how long they'd run like that before failing. How long do you need it to last?
I've run brushless computer fans at 15-16V w/o adverse effects. The same fan models can be had in very different power ratings so there may be big safety margins.
 

TheLaw

Sep 27, 2010
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I think fans/motors can run at higher voltages then they are rated for alright, but I think the manufacturers like to put a slightly lower voltage rating for reliability's sake. If you are trying to drive an industrial motor, it might be a different story than if you are using a PC fan motor with tiny SMD parts and 28 gauge wire.
 

barathbushan

Sep 26, 2009
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check the maximum voltage rating for the motor , before trying it . Motors can only take so much abuse they have been designed for
 

eptheta

Dec 20, 2009
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TheLaw, the motor only gets slightly hot, so i can't see why it won't last.

How long do you need it to last?

Well, i have about 240 holes to make on my PCB, and each barely takes 2s to make.
I made just 14 yesterday before the motor became rather hot, and I didn't want to destroy it right away.

It seems to work fine if I don't let it run continuously (about 4 seconds on, and then off for a second or so)

check the maximum voltage rating for the motor , before trying it . Motors can only take so much abuse they have been designed for
The rating says 12V, but I don't understand why higher voltages should be a problem.....


Oh and also, When i turn it on, there is a moderately large spark, but that doesn't seem to be doing much damage.
I'll try actively cooling the motor while I'm using it when I drill the remaining holes.
 

KMoffett

Jan 21, 2009
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I made just 14 yesterday before the motor became rather hot, and I didn't want to destroy it right away.
Why do you want to destroy it at all? :confused:

With higher than rated voltages motor draws more current than the internal wiring rated for. This produces a lot of heat that the motor is not designed to dissipate. Heat degrades insulation and dries out bearing lubricants. Higher voltage generally means higher speeds, which means higher centrifugal forces and more stress on rotors and bearings. All this is why motors have voltage ratings. But, it's your motor. ;)

Ken
 

barathbushan

Sep 26, 2009
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Why do you want to destroy it at all? :confused:

With higher than rated voltages motor draws more current than the internal wiring rated for. This produces a lot of heat that the motor is not designed to dissipate. Heat degrades insulation and dries out bearing lubricants. Higher voltage generally means higher speeds, which means higher centrifugal forces and more stress on rotors and bearings. All this is why motors have voltage ratings. But, it's your motor. ;)

Ken

This is the precise answer to the overvolting motor question , however you were mistaken where the motor draws more current ,as you might know current is analogous to torque which depends on mechanical loads , so without any loads it draws a specific current , and as you apply load , it draws more current , if you apply maximum mechanical load , it draws huge current in order to convert it to torque which drives the load .

so two things are bad for motors
1)overvolting
2)adding lots of load
 
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eptheta

Dec 20, 2009
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Why do you want to destroy it at all? :confused:

Hahaha, yeah I know it sounds silly. But until I find a 24V motor, I "am willing", not "want", to let it get destroyed.

In any case, I finished making all 240 holes within a few minutes... I got a thin gel pack out of the freezer, and wrapped it around the motor to keep it cool... Aside from the unusually large sparks (high current I guess?) it worked fine, and still works...

Let's just hope it serves me well until I find a better motor (or become rich enough to buy a PCB drill press !)
 

eptheta

Dec 20, 2009
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Sorry, I bought just one and that too for Rs.125 ! Way too much if you ask me.
 

eptheta

Dec 20, 2009
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Off topic: On another note, wow barath, 60+ posts in one day !!!

My drill still works ! Now i just have to get a better bit holder. Right now I'm using the hand drill's holder stuck with super-glue on to my motor... Not very sturdy nor reliable...
 

barathbushan

Sep 26, 2009
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oh really !! Right now i have my semester end , so i guess i have time to kill :)
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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oh really !! Right now i have my semester end , so i guess i have time to kill :)

I would tend to urge quality over quantity.

edit: Not that I think enthusiasm is a bad thing :)
 
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LTX71CM

May 23, 2010
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For anywhere from $20 &up you can buy a Dremel that can reach in excess of 30,000RPM. A Dremel is cheaper and designed for that speed and usage as compared to your motors. Save your motors for some other project and spend $30 getting a better tool for the job. For as much as you spent on those motors you could have even purchased the drill stand to use with the Dremel.

I have comments regarding your topic but it's potentially far reaching, I don't care to write an article at the moment. Most of the pertaining aspects have been touched on but heat, bearing type, brush type, duty cycle and manufacturing quality are key points to your question. Could it destroy the motors? Of course. Will it? Eventually.
 
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