Brushless (electronically commutated) motors have a rotor equipped with permanent magnets. This rotor is moved by a rotating field which is excited in the stator winding and controlled by the amplifier; there is no electrical connection between rotor and stator. The advantages of these motors are the good heat dissipation, the high overload capacity (full torque at standstill for an almost indefinite time) and the little maintenance required. The only wearing parts are the ball bearings of the motor shaft. This motor is especially suitable for continuous operation with high torques at speeds over 100rpm with a feedback of the rotor encoder signals by hall sensors (rotor encoder). If the feedback of the rotor position is affected by a resolver, the motor can be used as a highly dynamic element; even in the case of low speed the motor does not jerk on account of torque ripple.