Supply for 2 dc motors 3V with gear box

Hi,

i've 2 dc motors 3V with gear box and a arduino motor shield, and i don't know if a 6V power is enough to run the motors.

Thanks in advance

More than enough.

Thank you for the answer i can use a battery pack of 2 AA batteries. If use 2 dc 6V motor can i use a 6V alimentator that i connect on arduino uno board?

Maybe i understoop, i need to use a 9V battery to supply arduino uno board and a 4x AA battery holder (with the batteries) for the 2 DC 6v motor.

is it correct?

When I said more than enough, I really meant it, as in too much. Unless you're putting the motors in series, but I assumed you'd want to control them separately.

i thought that 6v supply is more than enough for 3v motors, but for 6V motors?

Maybe this is a good place to ask a question that will help out the OP on this one. I am interested in using PWM. I know that the pin on the arduino will not be able to power the motor. But if I use a separate voltage supply and use a transistor to control the motor that will work. Now comes the PWM question. If I use PWM on the base of the transistor will it control the motor? In other words if I have a 6 volt battery and give it a 50 percent duty cycle will I be giving the motor 3 volts? I'm sure this is an uneducated question but I am teaching myself this stuff so uneducated is a good exemplar. I'm not trying to hijack this thread I just thought the answer might help the OP.

if i've 2 dc motor 4.5V can i supply these with a 9V battery connect to arduino barrel jack?

Please don't bother powering motors from a 9 volt battery, unless your surname is Duracell or Ever-Ready. Can you give us some idea of your electrical background? Do you recognize the terms parallel and serial connection?

MillenniumBug: i thought that 6v supply is more than enough for 3v motors, but for 6V motors?

If you have a 6V supply, then you can drive any number of 6V motors, as long as the supply can provide enough current (amps). You have not told us what the amp draw is for each motor, nor how many amps (or milliamps) the supply can provide.

the current for each motor is 0.030A

30mA? Are you sure? A phone vibra can take up to 100mA.

sorry it's 800mA

but so i can't supply both arduino and motor with an only 9 volt battery connected to arduino's jack i look this site http://www.emartee.com/product/42001/ in point 2 say that i can use only VIN on arduino

That is correct – you can’t drive both the motor and the Arduino from a single 9V battery. It will sag before then – and run out of juice very quickly!
Also, the 5V regulator on the Arduino itself will not like you drawing 2*800+50 mA, or about 1650 mA.
And the “digital out” pins of the Arduino will not deliver anywhere near 800 mA, but you probably already know this. Thus, you need to use a MOSFET transistor or a motor control board to control the motor, assuming you have the right power source.

If you need a mobile power source, I would recommend two 3.7V LiPo cells, for a total of 7.4V. This is a little more than the rated 6V of the motors, but if you don’t run them too hot, you’ll probably not burn them out. You can drive the motors directly from the “+” of the battery, through a MOSFET transistor, into “-”/ground, and also feed the Arduino through the input power barrel from the same batteries. Remember to put a reverse diode and/or Zener across the motor so it won’t fry the controlling transistors when it stops.

I attach a very quick sketch. (That is missing ground to the Arduino – oops :slight_smile:
You probably also want 220 Ohm resistors into the gates of the transistors, and perhaps a 22k resistor from gate to ground to bleed down if power is removed from the Arduino.

If you need a mobile power source, I would recommend two 3.7V LiPo cells, for a total of 7.4V. This is a little more than the rated 6V of the motors,

can i connect the cell to the barrel jack of arduino?

Yes. 7.4V will drive the Arduino through the barrel jack just fine.

thank you very much