hi ,
i have some dc motors with encoders. there is a sticker on the motor with these lines ;
JGA25-370
DC6V210RPM
in my project i will using 12v line.
i want to use motors as wheels and i am just asking is it safe to run 6v motor on 12 line ? or anybody tried this ?
i found some spec table
mine one probably 6v with 34 gear ratio model
i need some advice guys thanks
is it safe to run 6v motor on 12 line ?
The motor will run about twice as fast at 12V, and burn out much faster. But it will run for a while, possibly throwing some sparks.
thanks for your fast reply 
i dont know much about electronics , still learning,
i measured stall currents at
6v 1.2 amp
12v 1.8 amp
It is good that you know about stall current! However, I would expect the stall current at 12V to be twice that at 6V. It is just the motor power supply voltage divided by the winding resistance (provided that the motor power supply is not current limited).
If you are using a motor driver and control the speed with PWM, do not run the motor full speed for long periods and it will probably be OK.
The important thing with a motor is the current in the motor coils. Usually when the spec mentions a voltage it means that at that voltage the current in the coils will not be excessive.
If you are using a higher voltage it will be able to force a higher current through the coils and the motor is likely to overheat and get damaged.
If you use PWM with analogWrite() to control the speed of the motor then you can safely use a higher voltage as long as you limit yourself to a suitable maximum PWM value. For example if you are powering a nominal 6v motor with a 12v power supply you should probably not exceed an analogWrite() value of 128 which is 50% of the max.
...R
thanks for your replies
ordered some tb6612 to drive , do i need to use one driver per one motor?
(i mean binding two channels to one motor)
sorry for that i dont like smoke at all but i cant stay away 