Solid State Relays (SSR) can perform several tasks that an Electromechanical Relay (EMR) can perform. However, unlike electromechanically relays, solid state relays contain no mechanical parts inside it.
Essentially, solid state relays are an electronic device that depends on the electric, magnetic, and optic properties of semiconductors and electrical parts to attain its function of isolation and relay switching.
What Is The Principle Of Solid State Relays Operation?
Solid State Relays are very similar to electromechanical relays, in which both a control circuit and an individual circuit is used for switching the load. Once the voltage is applied to the input of the solid state relays, the relay gets energized by a light-emitting diode, which is then beamed into a light-sensitive semiconductor. Later, the semiconductor is used for zero voltage crossover relays, which helps condition the control circuit to start the output solid state relay switch when the next zero-voltage crossover takes place.
In situations of nonzero voltage crossover relays, the switch on the output solid-state is turned on at the exact voltage level that it occurs during the crossover. The elimination of the input current disables the solid state and control circuit switch, which is turned off when the load current passes through the zero crossover point of its operation cycle.
What Are The Applications Of Solid State Relays?
Since the initiation of the solid state relay technologies, it has secured recognition in many fields and sectors, which had earlier been the exclusive domain of the Electromechanical Relays (EMR) or the Contactors.
Considering the latest recognitions, the significant portion of solid state relays growth comes from Industrial Process Control applications, including control structures such as heating or cooling temperature controls, electric motors, solenoids, regulators, controllers, and transformers. The applications of solid state relays are almost inexhaustible, but here are some of the important and common ones:
- Industrial Automation
- Electronic Machines
- Industrial Electrical Devices
- Packaging Devices
- Tooling Machinery
- Manufacturing Equipment
- Food Production Machinery
- Security Systems and Devices
- Fire Security Systems
- Dispensing Systems
- Production Equipment
- On-Board Power Control Systems
- Instrumentation Devices
- Elevator Control Systems
- Metrology Devices
- Entertainment Lighting Systems
What Are The Benefits Of Solid State Relays?
When used appropriately in the planned application, solid state relays present several features and characteristics that you will not find in electromechanical relays. Solid state relays offer improved reliability, extended, and longer service life. Simultaneously, it also drastically reduces the electromagnetic interferences and enables rapid responses apart from creating high vibration resistance.
Usually, the solid state relays don’t have any moving parts that can wear out or arc contacts to weaken or deteriorate over time, which are usually the primary reasons behind electromechanical relay failures.
Some standard benefits that solid state relays provide are:
- Operational Longevity and Reliability (> 109 Operations)
- Zero Voltage Turn-On Operation
- Low Electromagnetic Interference (EMI)
- Low Radio Frequency Interference (RFI)
- Shock Wave and High-Frequency Vibration Resistant
- Random Crossover Turn-On
- Proportional Control
- No Contact Bounce and Rebound
- Arc-Less Switching Procedure
- No Acoustic Noise
- Microprocessor Compatibility
- Prompt Responses
- No Interior Moving Parts
Synopsis Of Some Things To Consider About Solid State Relays:
- Control Voltage or Input voltage
You need to find the proper range of operation in terms of maximum turning-on and minimum turning-off voltages. Remember that the input resistance requirements can also help you determine the optimum value for maximum input current and, thus, enables you to choose your solid state relays accordingly.
- Maximum Turning-On Time and Turning-Off Time
You need to determine the requirements for the maximum response time between the on or off the transition from the input to the output mechanism.
- Load current
You need to find out if the solid state relays require a heat sink. Additionally, also verify the minimum load current for proper and effective operation.
Similarly, you need to figure out if you need zeroed solid state relays or non-zeroed solid state relays to help you with control regulations. Finally, you also need to consider the type of solid state relay mounts. Usually, PCB, panel, or DIN rail are used for mounting SSRs.
If you are confused about the different technicalities and need expert guidance, it is advised that you connect with a licensed electrical professional and inform them about your requirements. Based on your residential, or commercial, or operational requirements, they can suggest you the best of solid state relays and also help you with other electrical system mechanisms.