Servo Motors
Servo Motors

Servo Motor - Anaheim Automation's Servo Motor product line offers a wide power range from 0.2 kW to 5.0 kW (0.25-6.6 HP), with an optional speed rating, oil seal, brake, and shaft end. All of our AC Servo Motor series are equipped with a 2,500 Pulse Per Revolution (PPR), wire-saving Incremental Encoder. The EMJ, EMG, and EML series AC Servo motors are equipped with high-energy, Neodymium-Iron-Boron Magnets (NdFeB) to help maximize motor performance and efficiency. These AC Servo Motors offer precision control at an affordable price.


  • Rated Torque: 22-45 oz-in
  • Rated Speed: 3000 RPM
  • 40mm Frame
  • 70VDC or 220VAC Voltage
  • Brake Options Available
  • Rated Torque: 90-180 oz-in
  • Rated Speed: 3000 RPM
  • 60mm Frame
  • 120, 220VAC Voltage
  • Brake Options Available
  • Rated Torque: 338-1352 oz-in
  • Rated Speed: 1000-3000 RPM
  • 80-130mm Frame
  • 120, 220, 380VAC Voltage
  • Brake Options Available
  • Rated Torque: 538-1062 oz-in
  • Rated Speed: 2000-3000 RPM
  • 110-130mm Frame
  • 220, 380VAC Voltage
  • Brake Options Available
  • Rated Torque: 1352-2704 oz-in
  • Rated Speed: 1000-2000 RPM
  • 130-180mm Frame
  • 220, 380VAC Voltage
  • Brake Options Available
  • Rated Torque: 2025-5438 oz-in
  • Rated Speed: 1000-2000 RPM
  • 150-180mm Frame
  • 220, 380VAC Voltage
  • Brake Options Available
Fundamentals of Servo Motors

Helpful Information
Basics
The basic definition for Servo Motors is automatic devices that use an error-correction routine to correct the motion of the Servo Motors. Servo motors are used in closed loop control systems in which work is the control variable. The general term servo can be applied to systems other than a Servo Motors that use a feedback mechanism such as an encoder or other feedback device to control the motion parameters. Typically when the term servo is used it applies to 'Servo Motors' but this term is also used as a general control term with the meaning of a feedback loop to position whatever the item is including a Servo Motors. Servo Motors are different from other controlled motors in that they are controlled by a time-based derivative commonly referred to as the PID loop. Servo motors feature a motion profile, which is a set of instructions programmed into the controller that defines the servo motor operation in terms of time, position, and velocity. The Servo Motors that are used to control position must be capable of changing the velocity of the output shaft because the time-based derivative, or the rate of change of position, is velocity. These servo motors are much smoother in motion than a comparable stepper, and will have a much higher resolution for position control.

Cost
Servo Motors are considered one of the more expensive motors when compared to AC, Brushless, DC, Stepper, and other motor types. The reason for the expense of Servo Motors is the precision required to make Servo Motors and the expensive components that go along with Servo Motors. Generally speaking Servo Motors are intended to be a very precise positioning or speed control device. The motion should be smooth and very precise. To accomplish these features, Servo Motors are manufactured under very tight control parameters. Along with the cost of Servo Motors are the case, bearings, connectors, and feedback devices. The case is usually industrial grade, often sealed to achieve an IP65 rating or better. The bearings are high quality to make sure that the Servo Motors can run the speeds desired and can handle the appropriate axial and radial loads. The connectors are typically mil-style connectors that can be detached at the motor, but are very reliable and industrial grade. The Feedback devices are typically differential encoders and or resolvers. The devices are very expensive and add cost to Servo Motors.

Customizing
Anaheim Automation offers a variety of options to customize servo motors. This list includes, but is not limited to: shaft, brake, oil seal for an IP65 rating, mounting dimensions, speed, torque, and voltage. Please give Anaheim Automation a call for any custom applications where servo motors are used.

Feedback
There are two options for Servo Motors feedback controls, either a servo encoder or a servo resolver. A servo encoder and a servo resolver provide the same solution in many applications, but are vastly different. They are both used to sense speed, direction, and position of the Servo Motors output shaft. A resolver/encoder on different servo motors is a glass disc with very fine lines on it and an optical encoder that counts those lines as it rotates with the motor. This information is couple to the controller which tracks the counts, the rate that they go by, and through a host of feedback loops, logic, and controlling the amplifiers, produces the desired motion. The resolver on the Servo Motors use a second set of rotor and stator coils called the transformer to induce rotor voltages across an air gap. The resolver does not use any electronic components, therefore it's very robust with a high temperature range, and is inherently shock resistance due to its design. A resolver is mostly used in harsh environments. The optical encoder on Servo Motors uses a rotating shutter to interrupt a beam of light across an air gap between a light source and a photodetector, over time the wear associated with the rotating shutter reduces the longevity and reliability of the encoder. The application will determine whether a resolver or an encoder is needed. Encoders are more accurate and are easier to implement so they should be the first choice for any application. The only reason to choose a resolver is if environmental and longevity requires it.

History
The steam engine governor is considered the first powered feedback system that used a gain value so it is considered the first servo mechanism. The word servo motors comes from the French phrase Le Servomoteur or the slave motors. The first known record of its use was by JJL Farcot in 1868 to describe steam engines and hydraulics for use in steering a ship.

Types
There are two main types of Servo Motors - Rotary and Linear. Rotary Servo Motors Rotary Servo Motors are what most people think of when they think of Servo Motors. The three types of Servo Motors are: AC Servo Motors, Brush DC Servo Motors, and Brushless DC Servo Motors. The motion of rotary Servo Motors are often converted into linear motion by the use of a screw thread (ball screw or leadscrew), or with the use of belts and pulleys. AC servo motors have the advantage of being able to handle much higher current surges than brushed DC motors. Rotary AC Servo Motors are the AC type motor that is used with a feedback device. These are typically only used in smaller application because a large AC Servo Motors is typically too inefficient when compared to its DC or Brushless counterparts. Linear Servo Motors Linear Servo Motors are a flattened out Servo Motors where the rotor is on the inside, and the coils are on the outside of a moveable u-channel. Both Servo Motors types are becoming more popular as Servo Motors prices continue to come down.

What are Servo Motors
Anaheim Automation offers a wide variety of standard and Servo Motors. Occasionally, OEM customers with mid to large quantity requirements prefer to have Servo Motors that are custom or modified to meet their exact design requirements. Sometimes the customization is as simple as shaft modification, brake, oil seal for an IP65 rating, mounting dimensions, wire colors, or label. Other times, a customer might require that Servo Motors meet an ideal specification such as, speed, torque, and/or voltage. Engineers appreciate that Anaheim Automation's Servo Motors product line can answer their desire for creativity, flexibility and system efficiency. Buyers appreciate the simplicity of the one-stop shop, and the cost savings of custom Servo Motors design, while engineers are pleased with Anaheim Automation's dedicated involvement in their specific servo motor system. Anaheim Automation's standard Servo Motors product line is a cost-effective solution, in that they are known for their rugged construction and excellent performance. A considerable size of its sales growth has resulted from dedicated engineering, friendly customer service and professional application assistance, often surpassing the customers expectations for fulfilling their custom requirements. While a good portion of Anaheim Automation's Servo Motors sales involves special, custom, or private-labeling requirements, the company takes pride in its standard stock base located in Anaheim, California, USA. To make customization of Servo Motors affordable, a minimum quantity and/or a Non-Recurring Engineering (NRE) fee is required. Contact the factory for details, should you require custom Servo Motors in your design. All Sales for customized or modified Servo Motors are Non-Cancelable-Non-Returnable, and a NCNR Agreement must be signed by the customer, per each request. All Sales, including customized Servo Motors, are made pursuant to Anaheim Automation's standard Terms and Conditions, and are in lieu of any other expressed or implied terms, including but not limited to any implied warranties. Anaheim Automations customers for the Servo Motors product line is diverse: companies operating or designing automated machinery or processes that involve food, cosmetics or medical packaging, labeling or tamper-evident requirements, cut-to-length applications, assembly, conveyor, material handling, robotics, special filming and projection effects, medical diagnostics, inspection and security devices, pump flow control, metal fabrication (CNC machinery), and equipment upgrades. Many OEM customers request that we "private-label" the Servo Motors, so that their customers stay loyal to them for servicing, replacements and repairs.

What Industries are Servo Motors Used in
Servo motors are seen in applications such as factory automation, robotics, CNC machinery, and packaging. The feedback lets the drive know its position, speed, and torque to detect unwanted motion. Pharmaceutical industries are driven be the need to create smaller devices; ones that are easier to operate and function more efficiently.

How are Servo Motors Controlled
Servo motors operate on negative feedback, meaning that the control input is closely compared to the actual position via a transducer. If there is any variance between physical and wanted values, an error signal is amplified, converted, and used to drive the system in the direction necessary to reduce or eliminate error. Servo motors are controlled by a pulse of variable width that is sent from a micro-controller output pin to the servo motor's control wire. The shaft angle is determined by the duration of the pulse, also known as pulse width modulation (pwm). This pulse has to have specific parameters such as; minimum pulse, a maximum pulse, and a repetition rate. Given these constraints, neutral is defined to be the position where the servo has exactly the same amount of potential rotation in the clockwise direction as it does in the counter clockwise direction. It is important to note that different servo motors will have different constraints on their rotation, but they all have a neutral position, and that position is always around 1.5 milliseconds (ms).

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