Advice on controlling 12v dc motors speed

Using Arduino Motors, Mechanics, Power and CNC
#1

Hi.

I need to power 3 12v dc motors’ speed independently.

My motors specifications are very similar to this:

Nominal voltage: 12v
No Load speed: 7750rpm
No Load current: 0.4A
Stall Current: 15 A
Stall Torque: 2100g-cm

At Maximum Eff:

Speed: 6660 rpm
Current: 2.45 A
Torque: 295g-cm
Output: 20.14W
Efficiency: 68.5%

My question is, if i only need to control the speed (not direction), could a mosfet be sufficient to do so? and what type of mosfet?

And if i want to power three motors from a battery,what type/specification of batteries should i use (for a maximum of 3h, 90% of the time with no load)?

Thanks, and if possible some good links to tutorials on the principals of dc motors powerconsumption/power/control because i now little about them and don’t know where to start from :slight_smile:

#2

Hi,
Some starting info HERE thanks to Mike Cook..

And more HERE

A MOSFET like This One
might be good. There is a good article on this HERE

You'll want a silicon or Shottky diode across the motor is the reverse direction to handle spikes you will otherwise get.

IF you are going to speed-control these motors , drive their gates with a 100 ohm resistor from Arduino, and add a 10K or so resistor from Gate to Source to hold the FET off during powerup..

Batteries? You said about 2 Amps, 90% of the time so maybe 2 * .1 * 3 hours * 3 motors or about 2 Ampere-Hours.

Let us know how it goes...

DISCLAIMER: Mentioned stuff from my own shop...

#3

terryking228:
Hi,
Some starting info HERE thanks to Mike Cook..

And more HERE

A MOSFET like This One
might be good. There is a good article on this HERE

You'll want a silicon or Shottky diode across the motor is the reverse direction to handle spikes you will otherwise get.

IF you are going to speed-control these motors , drive their gates with a 100 ohm resistor from Arduino, and add a 10K or so resistor from Gate to Source to hold the FET off during powerup..

Batteries? You said about 2 Amps, 90% of the time so maybe 2 * .1 * 3 hours * 3 motors or about 2 Ampere-Hours.

Let us know how it goes...

DISCLAIMER: Mentioned stuff from my own shop...

Thanks a lot ^^

#4