Hollow Shaft Resolvers

Industrial Resolvers and Angular Position Sensors for Smart Motors

Resolvers are angular accuracy position sensors which can be used for position and velocity feedback in applications such as servo motors. Our Motor resolvers consists of a stationary stator and a movable rotor in terms of being a mechanical device. Electrically, it consists of a transformer for supplying the rotor with power and a second transformer for determining angles. As one of the largest sensor and connectivity companies in the world, we can offer shock and vibration resistant industrial resolvers, which can be connected with a wide range of servo motor connectors and further sensor application - specifically for your requirements.

Reliability and high precision. An accurate and reliable feedback system is the one of the most important parts of the industrial servo motor and drive units. Our reliable and high performance resolvers are engineered to provide a cost effective yet uncomplicated, versatile, proper, efficient and robust solution for this crucial system. Scroll down to learn more about our industrial resolvers - available in sizes 15 and 21.

Features

  • Non contact measuring principle
  • Robust against humidity and many lubricants
  • Resistant to shock (11ms sine): 1000m/s2
  • Resistant to vibration (0 ... 2 kHz): 200m/s2
  • Wide temperature range (-55°C to +150°C)
  • Low sensitivity to electromagnetic interferences
  • Angular information over 360°
  • Signal transmission over long distances without extra signal conditioning
  • High accuracy (typical angular between ± 4‘ and ± 20‘ arc minutes depending on the variant)
  • Max. permissible motor speed 20.000 rpm
  • Available in size 15 and 21 (diameter)
  • Available as single-speed and multi-speed (speed 1 to 4)
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Resolver size 15 - Compact design

Our size 15 resolvers are designed to meet challenging harsh environments in combination with small space requirements. Due to its compact design, our size 15 resolver offers high accuracy position feedback for a compact servo motor design. Furthermore, a variety of customer specific solutions in addition to motor cable assemblies can be provided.

Features

Resolver Size 15
  • Min. housing length: 16.1mm
  • Min. outer diameter: 36.83mm
  • Max. inner shaft diameter: 12.00mm
  • Weight: approx. 90g
  • Momentum of inertia of the rotor: approx. 20 g · cm2
  • Permissible radial runout: 0.075mm
  • Permissible axial offset: ± 0.25mm
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Resolver size 21 - More reliability

Our size 21 resolvers enable high accuracy angular position feedback as well as a lifetime above average. Size 21 resolvers are available with a variety of customer specific housing and shaft solutions, leading to reduced mounting and installation time.

Features

Resolver Size 21
  • Min. housing length: 27.0mm
  • Min. outer diameter: 52.40mm
  • Max. inner shaft diameter: 17.00mm
  • Weight: approx. 240 g
  • Momentum of inertia of the rotor: approx. 200 g · cm2
  • Permissible radial runout: 0.075mm
  • Permissible axial offset: ± 0.5mm
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Benefits

  • Reliability and high precision with low space requirements
  • Fully operable even under extreme environmental conditions
  • Stable against humidity and many lubricants
  • Resistant to shock and vibration
  • Lifetime above average due to the design of the mechanical structure and automated coil incorporation
  • Available as singleturn and multiturn variants
  • Direct connection with TE's Intercontec connectors

+/-6

angular accuracy in arc min

20000

maximum rotational speed in rpm

+150

maximum operating temperature in degree Celsius

Applications

  • Servo Motors
  • Robotics
  • Factory automation equipment
  • Textile weaving machines

Frequently Asked Questions (FAQs)

How does a resolver work and what does a resolver do?
Resolvers are angular position sensors which can be used for position and velocity feedback in applications such as servo motors. Due to its design, the hollow shaft resolver boasts of a service life, which is well above average. Reliability as well as high precision and low space requirements, supplement its favorable characteristics. It remains fully operable even under extreme environmental conditions. Essentially, the resolver consists of a stationary stator and a movable rotor in terms of being a mechanical device.

 

Electrically, it consists of a transformer for supplying the rotor with power and a second transformer for determining angles. The first transformer has a concentric design and is functionally independent of angle values. The second, angle-dependent transformer is made of a stator winding and a rotor winding. The windings of these two transformer components are designed such that the number of windings in the grooves correspond to the values of a sine.


Negative values are realized by reversing the direction of the winding. The stator coils consist of two similar windings that are fitted in a relative position to each other rotated by 90°. If the rotor winding is energized, a sinusoidal magnetic flux is created that induces voltages in the stator coils as a function of the relative angular position of the rotor and stator. The amplitudes of the two voltages correspond to the sine or cosine. Thus, using a suitable evaluation circuit, it is possible to obtain the absolute angle data (Sine ϕ / Cosine ϕ = Tan ϕ, where ϕ = shaft angle). The term used for the basic version is a resolver with one pair of poles (1-speed-resolver).


The number of pairs of poles indicates how often the sine distribution of the rotor and stator windings is repeated during one revolution. The higher the number of pairs of poles, the higher the mechanical precision of the resolver. With multiple pairs of poles, the absolute angle data can be lost but a higher resolution is possible after digital conversion of the resolver signals.

 

What is the difference between resolver and encoder?
Both devices (resolvers and encoders) are angular position sensors, meaning by converting the mechanical movement into electrical signals, they measure the rotary position of a shaft. Resolvers are much more robust against extreme environmental conditions such as high temperatures as well as shock and vibration comparted to encoders. Resolvers can serve as an alternative to the incremental and absolute encoders. Encoders provide a digital output signal whereas resolvers provide an analog output signal, thus requiring resolver-to-digital conversion. The decision between selecting a resolver or an encoder depends on the specific application, particularly on environmental conditions and on the control electronics. Resolvers are favorable for very harsh environments, but encoders can show high accuracy and are less complex to integrate into the control electronics.