Hudson Brushless Servo Motors Deliver High-Dynamic Performance at an Economical Price

Hudson brushless servo motors deliver high-dynamic performance at an economical price. Each brushless motor is optimized for a specific application.

They use a permanent magnet rotor that fits into a stack of stator laminations containing pole pairs oriented in an alternating north-south pattern. The rotor is supported by two rotary bearings. The motor also requires a feedback device to provide position and velocity data to the servo drive.

Benefits

The motor is an important tool that converts a type of energy into mechanical energy. Whether it’s the Nespresso machine, your father’s van or animated Santa’s at malls, we live in a world that is powered by motors. The most common kind of motor is electric, which converts a electrical current into motion that can move things around. Servo motors, in particular, are used for highly precise position and speed control.

Brushed DC motors rely on brushes and a commutator to switch current through the rotor windings as they rotate. This creates arcing that generates significant electrical noise and may cause damage to the motor. Brushed motors also have high inertia, which limits their acceleration and deceleration rates.

Brushless servo motors use permanent magnets and a fixed armature to eliminate the need for mechanical commutation. An electronic controller switches current to the armature windings in a way that mimics the commutation of a brushed motor. The benefit is much greater efficiency, longer lifetime, less expensive maintenance and reduced noise.

Additionally, Hudson servo motors feature a built-in thermal sensor that tells the servo drive when the encoder electronics are near their maximum safe operating temperature. This is an important feature because it prevents the motor from overheating and helps ensure the windings remain a full 65oC below their short-term maximum temperature rating. This is a key safety measure that reduces the risk of insulation failure, even in cases where the motor runs continuously for long periods of time.

Commutation

Brushless motors use an electronic commutation system instead of the mechanical commutator found in conventional DC brushes. This allows the current to be passed directly between the rotor and stationary part of the motor, without having to be switched via a commutator. This allows the motor to generate higher torque, be more compact and require less maintenance.

The electronic commutation system in a brushless servo motor uses an H-bridge composed of electronically controlled switches (transistors, IGBTs or MOSFETs) to control the direction and magnitude of brushless servo motor the current flowing into the coils of the permanent magnet. The switch(es) are energized in a sequence that changes the polarity of the current flowing into each set of coils. The polarity change is accomplished by pulse width modulating one of the switches – thus controlling speed or torque.

Because the electronic commutation system requires feedback devices (such as hall sensors or encoders) to operate, a brushless servo motor is typically more expensive than a brushed version. However, the increased precision they provide more than make up for the initial cost. The feedback devices report the position of the rotor magnets to the drive and synchronize the voltage applied to each set of windings so that each is always exposed to a magnetic field that will provide maximum torque in that position.

Feedback

A servo motor is a motor that uses feedback sensors to position devices to the exact location they need to be. This makes them an ideal choice for robotics and other automated machinery. Unlike DC motors, which use mechanical commutation, most brushless servo motors feature electronic commutation. They have a variety of feedback options that can be used in conjunction with the preferred type of commutation, which allows for greater control over speed and torque.

The feedback devices on a servo motor provide data that indicate the rotor’s rotational position and velocity. They interact with the servo drive to inform it of the motor’s position, and the drive adjusts its current flow to keep the motor’s shaft at the desired position. Depending on the feedback device, it may use either trapezoidal or sinusoidal commutation.

Brushed or not brushed, a brushless servo motor can be used in any system that requires precision positioning and the brushless dc motor driver ability to respond to input commands. They’re found in power tools, robots and other automation systems, vehicles, and drones. They also help make things we use every day work, including air conditioning in cars, and they’ll continue to be essential for years to come. When considering which motor to use, it’s important to consider the environment that it will be placed in, its power requirements, size and weight constraints, and the level of feedback required.

Design

A brushless servo motor does not use mechanical brushes and commutator that are exposed to the high risks of abrasion and wear. This motor type does not require a physical commutator so it can run at higher speeds and deliver more torque than its brushed counterpart.

Rather, a brushless motor uses a control circuit to switch high power transistors, which direct current to the motor coils. This is a more efficient design and reduces heat generation in the application. It also allows for close integration with the servo drive. This provides faster EtherCAT communication for deterministic closed loop control.

The motor has a shaft that connects to the load and a shaft coupler if applicable. The rotor has permanent magnet segments that fit within the shaft or embedded in a stack of stator laminations that are fitted to the motor’s outer diameter. These magnets are arranged in alternating pole pairs oriented north and south to create the magnetic fields that make the rotor rotate.

A servo motor requires an input signal that tells it how far and how fast to move the output shaft. This signal is provided by a position sensor that monitors the motor’s output shaft speed and position. Then, a control circuit constantly adjusts the power to achieve the desired position, velocity or torque.