Why do machines need relays?

Machines need relays because these essential electrical components serve as intelligent switches that control high-power circuits using low-power signals. Industrial relays act as protective intermediaries between delicate control systems and powerful machinery, enabling safe operation while preventing equipment damage. They provide electrical isolation, amplify control signals, and ensure reliable switching of motors, valves, and other critical components that keep production lines running smoothly.

Understanding the fundamental role of relays in machine operations

Machine relays function as the backbone of industrial automation by managing electrical circuits that would otherwise be impossible to control safely. These devices enable complex machine operations by creating a bridge between low-voltage control systems and high-power equipment components.

In manufacturing environments, control systems typically operate at safe voltages like 24V DC, whilst motors, heaters, and solenoid valves require much higher voltages and currents. Relays solve this fundamental mismatch by allowing small control signals to switch large electrical loads without direct connection.

The relay's electromagnetic or solid-state switching mechanism ensures that operators and sensitive electronic components remain isolated from dangerous voltages. This separation is crucial for maintaining both safety standards and system reliability in demanding industrial applications.

What exactly do relays do in machines?

Relays perform four critical functions in machine control: circuit switching, signal amplification, electrical isolation, and load control. These automation relays act as intelligent intermediaries that translate control commands into appropriate actions for high-power equipment.

Circuit switching represents the relay's primary function, opening and closing electrical pathways based on control signals. When a programmable logic controller sends a 24V signal, the relay responds by switching a 480V motor circuit, enabling precise control without exposing the control system to high voltages.

Signal amplification occurs when a weak control signal triggers the relay to switch much larger electrical loads. A milliamp control current can activate a relay that switches hundreds of amperes, providing the power multiplication necessary for industrial applications.

Load control encompasses the relay's ability to manage different types of electrical loads, from resistive heating elements to inductive motor windings, each requiring specific switching characteristics for optimal performance.

How do relays protect machines from electrical damage?

Electrical relays provide comprehensive protection through overcurrent detection, voltage regulation, arc suppression, and complete isolation between control and power circuits. These protection mechanisms prevent costly equipment damage and extend machine lifespan significantly.

Overcurrent protection activates when electrical loads draw excessive current, immediately opening the circuit before damage occurs. This rapid response prevents motor burnout, wiring damage, and potential fire hazards that could shut down entire production lines.

Voltage regulation ensures that sensitive equipment receives stable power supply conditions. Relays can disconnect loads during voltage fluctuations, protecting expensive automation components from damage caused by power quality issues.

Arc suppression technology, particularly in solid-state relays, eliminates the electrical arcing that occurs during switching operations. This feature prevents contact degradation and reduces electromagnetic interference that could affect nearby control systems.

Why can't machines operate reliably without relays?

Machines require relays for reliable operation because these components provide fail-safe functionality, redundancy systems, precise timing control, and consistent performance under varying environmental conditions. Without relay applications, industrial systems would lack the predictable behaviour essential for automated production.

Fail-safe operations depend on relays that default to safe positions when power is lost or control signals fail. This characteristic ensures that machines shut down safely rather than continuing operation in potentially dangerous states.

Redundancy systems utilise multiple relays to provide backup switching capability. If one relay fails, backup units maintain system operation, preventing costly production interruptions whilst maintenance teams address the issue.

Precise timing control enables relays to coordinate complex sequences of machine operations. From coordinating conveyor systems to managing heating cycles, relays provide the temporal accuracy necessary for consistent product quality.

Key takeaways for implementing reliable relay solutions

Successful relay benefits realisation requires careful consideration of application requirements, environmental conditions, and long-term reliability factors. Industrial engineers must evaluate total cost of ownership rather than focusing solely on initial purchase prices.

Environmental compatibility ensures that selected relays can withstand temperature extremes, vibration, and electrical noise present in industrial settings. Solid-state designs often provide superior performance in harsh conditions compared to electromechanical alternatives.

Maintenance requirements vary significantly between relay types. Solid-state relays typically offer maintenance-free operation with extended service life, reducing both labour costs and production downtime associated with component replacement.

For reliable relay solutions that maximise your automation system's performance and minimise maintenance requirements, consult with experienced professionals who understand the demanding requirements of industrial applications. Find your local Delcon distributor to discuss relay solutions tailored to your specific operational needs.


Hi! I see you're interested in machine relays and how they protect industrial equipment. Many engineers and automation professionals are looking to improve system reliability or solve specific control challenges. Which best describes your current situation?
That's exactly the kind of challenge solid-state relays are designed to solve. Quick question: How urgent is addressing this for your operations?
That makes sense. To point you in the right direction, what type of industrial loads are you primarily working with?
I understand the urgency. Let me connect you directly with a relay specialist who can help you address this quickly. They'll reach out to discuss solutions that minimize your downtime and prevent future failures.
Perfect! Based on what you've shared, I can connect you with someone who specializes in relay solutions for applications like yours. They can provide technical guidance tailored to your specific requirements.
Thank you! We've received your information. Our team will review your requirements and reach out to discuss relay solutions that match your specific needs and operational conditions.
Your local Delcon specialist will be in touch to explore how our solid-state relays can deliver the reliability and longevity your automation systems require.
+358 40 220 5823 
sales@delcon.fi 
VAT: FI18075473
Delcon Oy 
Veikkointie 4 
03100 Nummela 
Finland