i need to use an electric motor and i need to know how to change it to dc
U will need a power converer, they sell theses for cars at a auto place, there about $30 for a cheap one that should do for a small motor. A place like home depo might also have this
Basically you can't change the motor. You might be able to use an inverter which synthesises AC from the DC supply. As you give few other details I can't go any further on this one.
There are other ways to use an AC electric motor other than by using utility AC power. They all involve using an AC outlet. A DC to AC inverter has an outlet on it to plug you AC loads into. An AC generator (use good ventilation) has an AC outlet on it to plug your loads into. If you are using 12VDC from a car battery then inverters are available at automotive parts stores, department stores, truck stops, etc. They come in different power rating and you should reading the power rating of your motor to determine which one might work. the rating might be in HP, VA, Watts or FLA. The inverters are usually in Watts KVA or KW. If the only rating you have is HP then you need to multiply the HP by 1000 to get VA. 1000 VA is the same as 1 KVA. Watts is similar to VA. 1000 Watts is 1KW. On larger motors there is a something called locked rotor current. This is the current that the motor draws when you first turn it on. It is often about 6 times the FLA. This can be a problem for your system because it may overload the inverter when you start the motor. If the motor does start then it may take a while to get up to speed. Once it is up to speed then at full load the current shouldn't be more than the FLA rating. I hope this helps.
Hold on a minute. If you're thinking of running an AC electric motor on DC, forget it. It won't work. If the power available is DC, you need a DC motor that runs on the voltage you have available. Most common, single-phase, AC motors require 120 volts. You'd better regroup and reconsider your strategy.
