Measurement & Testing Systems
MagHyst® for Relays and Contactors

Relays and contactors have traditionally been regarded as purely switching devices. However, one important characteristic is often overlooked: every electromagnetic actuator possesses inherent sensing capabilities due to its magnetic circuit. These properties can be utilized for the highly precise determination of position, force, and overall system condition.
This is exactly the potential unlocked by MagHyst® technology.

By analyzing the electromagnetic signature of the actuator, the relay or contactor itself becomes a sensor. Without the need for additional sensors, the condition, quality, and aging behavior of the entire system can be continuously monitored.

Because relays and contactors are typically enclosed or fully sealed assemblies, the use of conventional position, displacement, or force sensors is often either technically impractical or economically unfeasible. Utilizing the existing excitation coil as an integrated sensor therefore provides a significant technological advantage.

Sensorless Real-Time Condition Monitoring

Virtually every fault that can occur within the electrical, magnetic, or mechanical subsystem of a relay or contactor influences the system's magnetization characteristic and therefore becomes measurable.
This applies during:

  • Research and development
  • Manufacturing
  • End-of-line testing
  • Endurance and lifetime testing
  • Real-world operation throughout the entire service life

Experience shows that the majority of failures originate within the mechanical subsystem. Wear, friction, spring fatigue, dimensional variations, and changes in contact mechanics often develop gradually and remain undetected for extended periods.
With MagHyst®, every switching operation simultaneously becomes a diagnostic cycle. As a result, faults can be identified long before they lead to functional failure.

Benefits Throughout the Entire Product Life Cycle

Research and Development

  • Analysis of electromagnetic and mechanical interactions
  • Optimization of magnetic circuits and actuator systems
  • Rapid root cause analysis of functional deviations
  • Reduced development times

Production

  • 100% in-line testing
  • Support for zero-defect manufacturing strategies
  • Immediate detection of production deviations
  • Reduction of scrap and rework
  • Root cause analysis instead of simple pass/fail evaluation

Testing Laboratory

  • Endurance and lifetime testing
  • Environmental chamber testing
  • Analysis of aging effects
  • Failure investigations and customer complaint analysis
  • Validation of new designs

Field Applications

  • Continuous condition monitoring
  • Predictive maintenance
  • Early detection of critical changes
  • Increased system availability
  • Improved functional safety

The Evolution of Switching Technology

While conventional combustion engines rely on numerous electromagnetic valves and pressure control valves, modern electric drive systems are increasingly centered around relays and contactors.
In electric vehicles, the number of hydraulic functions continues to decrease, while the number of high-performance electrical switching devices continues to grow. At the same time, increasing requirements for safety, reliability, and diagnostic capabilities are driving demand for intelligent condition monitoring solutions.
The experience gained with MagHyst® in applications involving solenoid valves, fuel injectors, brakes, and clutches can therefore be directly transferred to relays and contactors.

Which Faults Can Be Detected?

In principle, all faults that directly or indirectly influence armature position, magnetic force, or movement dynamics can be detected.

Electrical Subsystem

  • Shorted turns
  • Resistance variations
  • Inductance variations
  • Electrical contact issues
  • Coil aging effects

Magnetic Subsystem

  • Quality variations in magnetically soft materials
  • Effects of mechanical processing
  • Effects of thermal processes
  • Changes in permanent magnets
  • Batch-to-batch material variations
  • Eddy current losses
  • Deviations in the magnetization characteristic

Mechanical Subsystem – Position

  • Initial armature position
  • Final armature position
  • Contact gap
  • Overtravel
  • Total stroke
  • Armature motion profile

Mechanical Subsystem – Forces

  • Magnetic force
  • Contact force
  • Spring preload
  • Spring stiffness
  • Force hysteresis
  • Friction
  • Armature sticking
  • Armature bounce

Dynamics

  • Switching times
  • Pull-in and release behavior
  • Switching current
  • Switching voltage
  • Dynamic magnetic force
  • Dynamic armature position

Relays and Contactors as a Black Box – MagHyst® Makes Them Transparent

Conventional testing methods primarily evaluate the behavior of the contact system. The result is often limited to a simple "Pass" or "Fail" decision.
The actual root cause of a fault remains hidden and can often only be determined through time-consuming disassembly and laboratory analysis.
MagHyst® follows a fundamentally different approach.
Instead of evaluating only the outcome of the switching operation, the technology analyzes the electromagnetic signature of the entire system. This allows fault causes to be identified directly and enables production, assembly, or material-related issues to be localized much more quickly.
The black box becomes a transparent, diagnosable system.

Independent of Temperature and Supply Voltage

A key differentiating feature of MagHyst® technology is that measurement results can be evaluated independently of coil temperature and supply voltage.
These parameters are subject to significant fluctuations in real-world applications. Whether during endurance testing in environmental chambers, industrial operation, or vehicle applications, the diagnostic capability remains reliable even under extreme conditions.

Typical operating conditions include:

  • Temperatures ranging from −40 °C to +120 °C
  • Significant supply voltage fluctuations
  • Varying load conditions
  • Long-term aging processes

From Relay to Smart Relay

MagHyst® technology enables the next evolutionary step in electromagnetic switching devices.
By utilizing the existing actuator as an integrated sensor, intelligent components with built-in condition diagnostics become possible.

A conventional relay becomes a Smart Relay.

A conventional contactor becomes a Smart Contactor.

This makes it possible to detect aging effects, wear, and critical changes at an early stage, without additional sensors, without modifications to the design, and without requiring additional installation space.
For manufacturers, this means higher product quality and lower failure-related costs.
For operators, it means increased availability, improved safety, and the ability to implement predictive maintenance strategies.

MagHyst® transforms every switching operation into a diagnostic event and every relay or contactor into an intelligent source of information about its own condition.