HI, please help me... I am thirsty for any insights to my problem. I have a motor: Output: 60W VOLT:12V DC AMP: 7.5A RPM:1800 TORQUE: 3.5kgcm I have a motor reducer: for converting rotation movement of motor to up and down motion(for lifting heavy load) look like this http://www.yhcdsb.com/Eweb/uploadfile/20120405235504775.jpg [Broken] It has a speed reduction ratio of 12:1. Based on theory, if I have a 3.5kgcm input torque to the motor reducer,I will get 3.5kgcm x 12= 42kgcm from the motor reducer. It means that I will have no difficulties in lifting loads less than 30kg without damaging the motor, right??? The problem is I tried both AC and DC motors. Both of them have difficulties lifting the 30kg loads and generate high heat which cause the motors to slowly die out. I have checked the circuitry and no problem was found on the power supply. I am really confused about the gear ratio stuff... I get my speed reduced by a factor of 12. Does it mean that my torque is multiplied by a factor of 12 too??? It seems not to be the case. Does the efficiency of the motor reducer places an important part on it???? how significant is it?