How Solid State Relays Can Improve Your Manufacturing Process

1. Faster Switching Speed: SSRs use semiconductor components to switch the load, which enables them to switch on and off much faster than electromechanical relays. This quick response time is beneficial in applications where precise control or timing is required. For instance, in a PID temperature control loop with time proportional output (50% output = 50% of the time contacts are open, 50% contacts closed). The PID controller will have a configurable time proportional cycle time which would typically be set at say 30s for electromechanical contactors and 1s for solid state relays. In practice this means that an electromechanical contactor would open for 15s then close for 15s at 50% output whereas a solid state relay would be switching on for 0.5s then off for 0.5s at the same output. What this means for your process is that process temperatures can rise and fall significantly, especially those with a short time constant, as contactors switch in and out relatively slowly. Solid state relays with their fast switching rate deliver energy to the process in short bursts that appear almost continuous resulting in much tighter temperature control.

2. Reduced Arcing and Wear: Electromechanical relays have moving parts that can experience arcing and wear over time. SSRs have no mechanical parts, reducing the risk of arcing, making them more durable and reliable in high-frequency switching applications. Solid state relays can significantly decrease both downtime and maintenance costs.
For inductive loads, such as transformer primaries, where arcing (on electromechanical devices) and high peak currents are likely, specialised solid state relays that delay turn-on from the voltage zero-cross point can greatly reduce these peak currents.

3. Silent Operation: Unlike electromechanical relays, SSRs operate silently because they don't have moving parts that generate noise. This is particularly advantageous in noise-sensitive environments or when avoiding audible disturbances is important.

4. Longer Lifespan: SSRs typically have a longer operational lifespan than electromechanical relays due to their reduced wear and tear. This results in reduced maintenance and replacement costs over the long term.

5. Lower Power Consumption: Solid state relays and contactors require very little input power. An electromechanical contactor or relay requires considerable “coil current” to switch high current/power loads. Since the relay does not have to energize a coil and physically open and close contacts, it typically consumes 75% less power than EMRs.

6. Shock and Vibration Resistance: Solid State Relays have no moving parts and are entirely enclosed in a sealed housing making them well-suited to harsh environment applications. In addition they are not susceptible to accidental switching due to contact “bounce”. This makes them ideal for high vibration environments, such as railway & rolling stock application.

7. Diagnostic Features: Solid State Relays can incorporate diagnostic functions such as load current monitoring, partial load break detection, open load detection and short-circuited SSR detection