changing the direction of an electric motor

i can help you but i shoold know the type of the motor DC motor asynchronious or synchronious or other

synchronous, it's a stepper motor

Dear

Sir

We have one electrical motor With specification as below . As the direction of rotation of the motor is marked on it . I Would like to know , can the direction of rotation be changed like other three phase induction motors, as it has to be used for driving a fire pump . You reply on this subject will be appreaciated

Power 250 KW , 6.6 Kv Medium voltage , 3 phase, 50 Hz .

Awaiting your reply

thanking you

Jabi john

Techniq International

jabel Ali free zone

Dubai

United Arab Emirates

Email Id : Jabi@techniq.ae or John_jabi@yahoo.com

Power it off, remove power completely, open plate on the side of the motor and swap the connection of one of the phases with another coming from the starter, or do it in the starter itself, it does not matter which phases are swapped, but ONLY two!, the motor will now run in the opposite direction.

synchronous, it's a stepper motor

Since when are stepper motors synchronous? or the other way round?

Do you really know exactly what motor you have or am I missing something important?

For simplicity, a DC motor (with step down gearbox) with a permanent magnet field is very simple to reverse and with PWM, to control its speed, and should be more than powerful enough for a miniature crane.

AC motors are harder and need a lot of good "know how" that you do not possess....

Stepper motors with the right control electronics are relatively easy, but do not provide much power/torque....

You should specify motor perticularly the size relating voltage and wattage any permanant magnet DC motor can reverse its rotation with change in polarity , you can do it by electronics circuits simply using transistors ,capacitors and resistors , also through dedicated programable chips that are cheaper , to change state you can incorporate 555 timer or likes that can be triggered by optical switch ,and to drive motor you can use microrelay that uses quiet tiny amount of current for latching or transistor .