Resolver | Roll Forming Machine Motion Feedback

Resolver

1. Technical Definition

A resolver is an electromechanical rotary position sensor used to measure the angular position and speed of a rotating shaft. It operates using electromagnetic induction rather than optical or magnetic pulse detection.

Resolvers are commonly used in industrial machinery where extremely reliable motion feedback is required under harsh operating conditions.

In roll forming machines, resolvers are often used in:

• Servo motor feedback systems

• Drive motor position sensing

• Flying shear control systems

• Automated carriage drives

• Heavy-duty motion control applications

Resolvers are known for their durability and resistance to vibration, heat, dust, and electrical noise.

2. Where It Is Located

Resolvers are typically installed inside or directly attached to electric motors or drive shafts.

Common installation locations include:

• Servo motors

• Main drive motors

• Position-controlled carriages

• Flying cutoff drive systems

• Servo-driven feed systems

They are mounted directly on the rotating shaft to measure angular movement.

3. Primary Functions

3.1 Measure Shaft Position

Resolvers provide continuous angular position feedback.

3.2 Monitor Shaft Speed

They allow control systems to calculate rotational speed.

3.3 Provide Motion Feedback to Drives

Resolvers send position signals to servo drives or motion controllers.

3.4 Support Precision Machine Control

They help ensure accurate positioning of machine components.

4. How It Works

Resolvers operate using electromagnetic transformer principles.

Typical operation process:

1. An AC excitation signal is sent to the resolver rotor.

2. As the rotor turns, the magnetic field changes.

3. Two stator windings generate sine and cosine output signals.

4. The servo drive processes these signals.

5. The control system calculates the exact shaft angle and speed.

This allows continuous measurement of shaft position.

5. Types of Resolvers

Standard Resolver

Provides basic rotary position feedback.

Brushless Resolver

Uses electromagnetic coupling without physical electrical contacts.

Multi-Speed Resolver

Provides higher position resolution for precision applications.

Integrated Motor Resolver

Installed directly inside servo motors.

6. Construction & Materials

Resolvers are built using robust electromechanical components.

Common materials include:

• Laminated steel magnetic cores

• Copper windings

• Aluminum or stainless steel housings

• Precision rotor and stator assemblies

Important structural components include:

• Rotor winding assembly

• Stator winding assembly

• Bearing support

• Electrical connection terminals

These components allow reliable electromagnetic sensing.

7. Design Considerations

Engineers consider several factors when selecting resolvers.

Important considerations include:

• Angular resolution requirements

• Operating temperature range

• Electrical interface compatibility

• Mechanical mounting configuration

• Environmental durability

Resolvers are chosen when reliability is more critical than extreme resolution.

8. Load & Stress Conditions

Resolvers must withstand:

• Continuous shaft rotation

• Machine vibration

• Temperature fluctuations

• Electrical noise from drives and motors

Resolvers are designed to operate in harsh industrial environments.

9. High-Speed Production Considerations

High-speed roll forming machines require reliable motion feedback for servo-controlled equipment.

Resolvers provide stable feedback signals even under vibration and electrical interference.

10. Heavy Gauge Applications

Heavy gauge roll forming machines often operate in harsh environments where resolvers offer superior durability compared to optical encoders.

11. Light Gauge Applications

Light gauge roll forming machines may use resolvers in servo drive systems for precise positioning and speed control.

12. Common Failure Causes

Resolvers may fail due to:

• Electrical winding damage

• Excessive mechanical shock

• Cable or connector faults

• Severe overheating

However, resolvers generally have very long service lifetimes.

13. Symptoms of Resolver Issues

Technicians may observe:

• Servo drive position errors

• Motor control instability

• Incorrect shaft position readings

• Machine synchronization faults

These symptoms may indicate resolver malfunction.

14. Installation Requirements

Proper installation of resolvers includes:

• Mounting directly to the rotating shaft

• Ensuring correct rotor alignment

• Connecting resolver wiring to the servo drive

• Verifying signal calibration

Proper installation ensures accurate position feedback.

15. Maintenance Requirements

Routine maintenance should include:

• Inspecting wiring and connectors

• Checking mounting alignment

• Monitoring servo drive feedback signals

• Verifying resolver signal stability

Resolvers typically require minimal maintenance.

16. Typical Replacement Cost

Resolver costs vary depending on resolution and motor integration.

Typical price ranges include:

Standard industrial resolver
$150 – $400

Heavy-duty servo resolver
$400 – $900

Integrated motor resolver system
$900 – $2500+

Costs depend on design and manufacturer.

17. Safety Considerations

Failure of a resolver may lead to:

• Incorrect servo motor positioning

• Motion control errors

• Flying shear synchronization faults

• Reduced machine automation accuracy

Reliable motion feedback is critical for safe machine operation.

18. Role in Roll Forming Machine Assemblies

Resolvers provide motion feedback for roll forming machines including:

• Servo motor control systems

• Flying shear positioning

• Automated carriage drives

• Coil feed servo systems

• Precision motion control assemblies

They ensure stable and reliable motion feedback for automated machinery.

Engineering Summary

The resolver is a rotary position sensor that measures shaft angle and speed using electromagnetic induction.

It:

• Provides continuous position feedback

• Supports servo drive motion control

• Operates reliably in harsh environments

• Resists vibration and electrical noise

• Improves machine automation accuracy

Resolvers are durable motion feedback devices used in roll forming machines where reliable servo motor control is required.

Technical FAQ

What is a resolver?

A resolver is an electromechanical sensor used to measure the rotational position of a shaft.

Why are resolvers used in roll forming machines?

They provide reliable motion feedback for servo motor control systems.

Where are resolvers installed?

They are usually mounted on servo motors or rotating machine shafts.

How is a resolver different from an encoder?

Resolvers use electromagnetic signals while encoders typically use optical or magnetic detection.

What happens if a resolver fails?

The servo system may lose accurate position feedback, causing motion control errors.