How can i find the Voltage Current Ratio of a DC motor?
you can guess the voltage and current rating by looking at coil thickness , resistance , the shaft type ( high torque motors draw high current and have thicker and stronger shafts if you know the speed of it try driving it with a variable voltage variable current power supply and increase the voltage until the rated speed is obtained . if you do this properly you will find out without burning the coil does it have a name plate ,model number, company name or anything.
At least you have to find out one of these things. Voltage, Current, Speed or Power. Otherwise much difficult to find the exact voltage and current. The current and speed varied by the load of motor so you can not justify the right voltage without one of above mentioned value, only guessing. Determine the load of motor arrange to run the motor with that specific load connect with variable DC power source varie the voltage upto the required speed or power of motor by calculating P = V * I . More possible you will burn the motor. There is many other ways but it need the additional informations like no. of poles, size of wires, turns per coil, type of armature winding, no. of armature coil & size of wire, resistance of motor, it will puzzel you. Use the practical guess as above mensioned.
