Definite-purpose motors are AC motors with mechanical features designed for a specific purpose or application. They are powered by alternating current and require low power to start. The 50 Hz motors are for use on 50 Hz equipment based on European standards. Brake motors hold equipment at a standstill when power is cut to the motor. Instant reverse motors provide instant reversibility with a moderate starting force. Stationary power tool motors operate metalworking and woodworking equipment. Vector (inverter) AC motors provide continuous constant torque performance across an entire speed range. Vibrator motors promote material flow while brushless blowers have a high power-to-weight ratio for hand-held power tools.