How a Servo Motor works    

          The industrial robot needs a drive with particularly high demands. How a Servo Motor works ?Not only does the robot have to be able to accelerate and decelerate fast – also precisely positioning is required. In fact, here is a three-phase servomotor installed. 

        In this Article, we will first clarify the term servomotor and servo drive in general, then the 3-phase-servo drive. The servomotor is a part of a servo drive- whether brush less DC motor, synchronous or a robust asynchronous motor. But one thing in common is the detection of the rotor position by a sensor. This can be a resolver or an encoder. The sensor device gives feedback to a controller to keep.

       for example,

         The rotational speed or torque constant or to reach the target position as fast as possible. A servo motor system includes the servo motor with its feedback device, a servo amplifier and a controller. But how these devices work together? 

         The servo controller sends low voltage control signals for position, speed or torque to the servo amplifier. Now these commands are amplified up to high power, which the motor can use. The electrical pulses of a sensor are sent back to the amplifier. This amplifier uses this information to control speed and rotor position. The job of the servo motor controller, also named as the motion controller, is to close the loop on the system. By constantly interchanging data with the servo amplifier, the motor parameters like torque, speed or position can be adjusted immediately. Some manufacturers offer modules, which combine the controller and the amplifier. So you would have fewer parts, fewer connections and a smaller footprint.

          Talking about an AC servo motor you usually mean a 3 phase synchronous motor whose rotor field is excited by permanent magnets. So you can get a very powerful and brush less motor of small size. The stator winding produces a rotating magnetic field whose rotating speed and force is controlled by the amplifier and controller. In order to position quickly, all these motors must have a low moment of inertia, which can be achieved by an elongated shape.

Difference between AC Servo Motor and DC Servo Motor

• DC  has each a positive and a negative terminal, with this flowing within an equivalent direction between every terminal.
• AC operates in reverse,wherever this alternates fifty or sixty times per second, relying upon the region.

Now we will discuss that difference between AC servo Motor and DC servo Motor.

• AC Servo Motor Deliver Low power output of about 0.5 Watt to 100 Watt. On the otherwise DC Servo Motor deliver high power output.
• AC Servo Motor Efficiency is less about 5 to 20%. Other hand DC Servo Motor has High efficiency.
• AC Servo Motor Due to absence of commentator maintenance is less. DC Servo Motor Frequent maintenance required due to commentator.
• Stability problems are less in the AC Servo Motor. Otherwise DC Servo Motor more problems of stability.
• No radio frequency noise in the AC Servo Motor. In DC Servo Motor Brushes produce radio frequency noise.
• AC Servo Motor Compare to DC servo motor,it is relatively stable and smooth operation.
• DC servo motor is Noisy operation. AC amplifier used has no drift in AC servomotor.
• DC Amplifier used has a drift in DC servomotor.