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Potentiometer

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J.M. Millern

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Having questions on a new project. I assembled a potentiometer between my battery case and my 1.5-3dc hobby motor, and everything works though my batteries are getting hot quickly. Is there a step that I'm missing? Do I need to install something else or is this normal? It's a project for a display board. Yes, I am clueless when it comes to electronics.
 
With the information you've supplied, your overloading your "battery case" source of power.

Can you provide some additional information?

What does the battery case have in it? (# of, and what size batteries)?

What can you tell us about your potentiometer?

Do you have any more information about the hobby motor and anything else you might think important.

This will help us better understand what is going on.
 
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Without much to go on, my guess is that the batteries are not rated for the current draw of the system.

Speed control of a motor is bet done using PWM or Pulse Width Modulation. It will give you the best battery life.

The potentiometer may also not be sized properly. It has a wattage rating that can't be exceeded. Look up Ohms law.
 
What I have is a 2-AA battery case, and a 500k-ohm RadioShack push switch potentiometer. It's for a display board for a school project. The hobby motor is a 1.5 to 3 dc
 
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Yes ...your messing a bit..You require a motor controller..

https://freecircuitdiagram.com/2009/02/01/pwm-motor-control-circuit/


Or you find yourself a rheostat control..like the cheaper ones used in the slot car hobby

A rheostat is similar a potentiometer only it handles more current ..
If theres a hobby shop near you..that does RC boats.. ask if they have the Dumas 6 volt speed control.Its like $20 or something ..and hook your self up with 6 volt battery or pack..Sealed lead acid works well..
You motor is most likely a Mabuchi 180 ..it can handle 6 volt for a period of time with minimal load.. I run the same motor and battery in a small RC ship.. only I use an Electrionic speed control..
you may well want to get yourself another battery case say 4 cell ,a 3volt motor on a 3 volt battery, well quickly draw increased current once the voltage drops..

what your describing is no different than what the RC guys get when they begin to draw 30+ amps from their battery packs..the fast discharge really gets them warm fast
 
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The motor draws 2.6A (!) when it starts running and when it works hard.
The very high resistance "volume control" is designed for an extremely low current and if it was used to apply power to the motor then now its low resistance range is burnt out or is shorted.

A new AA alkaline cell or a few in series can provide 1A of current only for a couple of minutes before its voltage drops like a rock.
 
J.M.,

Is controlling the motor speed a necessary part of the display while it is being viewed?

Or is is just for setting up the display?
 
the 2.6 amp is stall current, take the motor and bind up the shaft on 3v.. I have done this.
The motor runs quite happliy on a 750 ma fuse start ,stop,full ahead to full astern,on a direct drive propellor thats 20mm dia 4 blade's, with a modified pitch,to get more top end speed,and better astern manuovering, the only time I have popped the fuse is when i dredge up weeds,feathers,plasitc bag's ,old fishing line,and ,,the worst...spent condoms..

I use a light fuse because the speed control is 5amp maximum, with a low duty cycle. In fact alot of the speed controls on the market for RC are over rated..Often benchmarked in perfect condition's ..
 
Why is the speed control pot a 500,000 ohms extremely low current volume control instead of maybe a 100 ohms wirewound power variable resistor?
But today nobody uses a resistor in series with a motor to control its speed.
 
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