Elec motor voltage

Started by swoffer, February 07, 2018, 11:57:27 AM

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Tiddlerbasher

Resistors are not polarity sensitive. You can fit them whichever way round - they just have a very limited function - they resist.
For a VERY simple explanation of electricity.
Think of plumbing.
Hold a pipe vertically - the distance in height from one end to another is similar to voltage - a potential difference.
Water will flow more quickly through a vertical pipe than one near the horizontal = more voltage means more current for a given wire (pipe)
Now increase the bore of the pipe = less resistance more flow = less resistance more current - amps.
Greate pressure of water - more volts = greater flow = more amps
Simple equations Ohm's Law - Volts (V) = Resistance (R) x Amps (A) or A = V/I or R = V/I also Power (simplified) = V x I

Gfish

#16
Cool. Good visual explaination. Missed what "I" was. Is it = to Watts. Good to know 'bout resistors. Sorry for the thread tangent, Swoffer.
Gfish
Fishing tackle is an art form and all fish caught on the right tackle are"Gfish"!

STRIPER LOU

Gfish, there's no need for a converter. A bridge rectifier does the job of converting the AC to DC.

................Lou

swoffer

AH , thanks so much for all the input guys .

Ive got my head around how these PWMs work now .

I've ordered one off Ebay , $1.72 with free postage , unfreekin believable how they can do it for the price .

Anyway I'll try it and see .

Again thanks for the pointers , I knew I would get good advice here .

Tiddlerbasher

Swoffer - the price thing is easy - big country - billions of people - they make a few cents on each product - they are all trying to make money. Every country has done it at some time or another :-\
The point is it will do the job :)

Ron Jones

Brian has to be correct. If he is using a 3 volt power supply then it's almost got to be a dc motor. An idea, buy a charger and some rechargeable D cells. You know they give you what you want.
Ron
Ronald Jones
To those who have gone to sea and returned and to those who have gone to sea and will never return
"

Tiddlerbasher

Ron - my rod wrapper was originally battery powered. Until I finished wrapping some guides - I set the motor speed to slow applied the epoxy and left overnight to set. The batteries died in the night. The epoxy sagged and dripped. It was a royal pita to clean up and redo. After that I fitted a mains power pack.

swoffer

Quote from: Tiddlerbasher on February 08, 2018, 11:42:27 AM
The batteries died in the night. The epoxy sagged and dripped.

Yep , my biggest concern as well with the battery option .

Three se7ens

#23
Quote from: Bryan Young on February 07, 2018, 02:16:54 PM
Quote from: swoffer on February 07, 2018, 01:23:07 PM
Awesome TB , how bloody cheap are they eh .

So just to be sure , if I get this one  

DC 1.8V 3V 5V 6V 12V 2A motor speed controller 30W PWM 1803b K7 L6

And say input 6v I will be able to turn it down to 1.8 v , do I understand that correctly ?

Thanks heaps .



AC and DC motors work very different.  A DC motor will not work if you reduce the voltage.  It will only work at the proper voltage rating of the motor (+/- tolerances).  What drives the motor faster or slower is the effective overall current provided to the motor.  Note that the motor will only take a maximum prescribed current and you cannot push more current to make the motor faster even if you wanted to.  What a PWM device does it controls the amount of pulse current going to the motor.  The closer the pulses are together, the faster the motor will operate.  The wider the time between pulses will slow the motor.  In short, the speed of the motor is controlled by the current, not the voltage.


Just to be clear on this, in a DC motor, voltage determines rpm, and amperage determines torque.

In an AC motor, frequency determines rpm, and amperage determines torque. 

swoffer

Quote from: Three se7ens on March 14, 2018, 04:25:39 AM
  A DC motor will not work if you reduce the voltage.  It will only work at the proper voltage rating of the motor (+/- tolerances). 

Hmmmm , dont know about this as I'm not a sparkatron at all , what I do know is the motor is rated for 3 volts and running it on 1.5 v caused it to run fine just at 1/3 the revs of 3 volts .

Any way I got the little modulator thingy in the post the other day , wired it in and it works perfectly . It has a dial on it that allows the rod turner to run at any revs I want from 0 to 50 . So in the end its just what I needed .

Cheers for the input guys .

Al

Carl L

Print a copy and put it in your files... I refer to this regularly.. Carl, KF5SPZ..

gstours

So what I see and hear is waay cool(good)...  first thing is in watching the post I've learned stuff,  the question was answered,  you learn something,   The price is right!   Thanks again to all of the people who have made this forum work.    And work well.....🙏🙏

Ron Jones

I'm glad it is working. I never thought I'd see the day where a PWM would be as cheap as a potentiometer. Really, anything would do that would change voltage to the minimum that will spin the motor will do. 3-7s is absolutely correct, a DC motor will only spin in its designed voltage range, but I have been surprised often at how wide that range is.
Glad it all worked out.

NOW SHOW US PICTURES OF YOUR WRAPPED RODS!!!

Ron
Ronald Jones
To those who have gone to sea and returned and to those who have gone to sea and will never return
"

Three se7ens

Quote from: swoffer on March 14, 2018, 07:43:06 AM
Quote from: Three se7ens on March 14, 2018, 04:25:39 AM
  A DC motor will not work if you reduce the voltage.  It will only work at the proper voltage rating of the motor (+/- tolerances). 

Hmmmm , dont know about this as I'm not a sparkatron at all , what I do know is the motor is rated for 3 volts and running it on 1.5 v caused it to run fine just at 1/3 the revs of 3 volts .

Any way I got the little modulator thingy in the post the other day , wired it in and it works perfectly . It has a dial on it that allows the rod turner to run at any revs I want from 0 to 50 . So in the end its just what I needed .

Cheers for the input guys .

Al

Sorry, I did not say that part.  I just had the message quoted wrong.  Its fixed now