Common carrier. A common carrier in common law countries (corresponding to a public carrier in civil law systems, usually called simply a carrier) is a person or company that transports goods or people for any person or company and that is responsible for any possible loss of the goods during transport.
Best Answer: Torque is a twisting force. It is the power output of an engine at one specific point in time. The first number, 200 in your expample, is the amount of torque. In America is is measured in foot/pounds. The second number, 400 in your example, is the RPM where that torque number occurs.
Torque motor principle. Torque motors are a special class of brushless permanent-magnet synchronous motors. Since the payload is directly connected to the rotor without the use of transmission elements, torque motors are classified as direct drives. Depending on your perspective, a torque motor is either a rolled-up linear motor or a classic servodrive with a large number of poles.