An important issue that comes to mind when it comes to designing or maintaining industrial automation systems is the question as to how a specific supply of relays should be used to control electrical circuit relays. Solid state relays (SSRs) and electromechanical relays (EMRs) are among the most frequently used ones. Although the two play very important functions in regulation of electrical systems, they are quite different in their construction, functionality, and various applications. In the following article, we will compare these two kinds of relays so that you can know which one is suitable for your system, particularly when you work with electrical relay manufacturers and you want to connect different types of industrial electrical components on your system.
Understanding Solid State Relays (SSRs) and Electromechanical Relays (EMRs)
Solid-state relays (SSRs) are a relay that employ semiconductor devices in a switching action; these devices are usually thyristors (“SCRs”) or triacs. In contrast to the electromechanical relay, SSRs do not have any parts in motion and are thus more reliable, and applicable to high speed switching purposes. The main strength of SSRs is the low power loss and wear and tear, which they experience since they do not involve physical contacts, which could accelerate wear down with time. They are used by applying input control signal to cause a semiconductor to conduct and causing the electrical circuit to be opened or closed. These relays find diverse applications where quick switching performance, increased operation life and little electrical noise is required. The lack of moving parts also implies that SSRs are much better against vibration, shock and extreme temperature, making them well-suited to industrial use. Electromechanical relays (EMRs) on the other hand are devices that involve an electromagnetic coil, and mechanical contacts that open or block an electric circuit. When an electric current is placed through the coil, there is a magnetic field generated which will attract or repel a mechanical arm such that the contacts either connect or break open. These are more conventional and can be used to perform multiple functions including motor control, alarms as well as sensors. They are usually relatively cheap and easy to apply as opposed to SSRs.
Key Differences Between SSRs and EMRs
Switching speed and reliability is the main contrast in solid-state and electromechanical relay. SSRs are much quicker in switching operation than EMRs. On the same note, whereas an electromechanical relay can take milliseconds to complete a switch, a solid-state relay can accomplish the same thing in microseconds, thus making SSRs perfect to use in high-frequency switching functions. Also, SSRs do not involve any movable parts and are therefore much more durable and reliable in the long run. Conversely, EMRs have a short life span and need to be serviced more frequently, given that they are subjected to physical contacts and are prone to mechanical elements. The other significant difference is based on the level of noise or electromagnetic interference (EMI) produced. The fact that EMRs have mechanical contacts also results in them generating more electrical noise which might interfere with your sensitive automation equipment. SSRs are solid-state and non-physically contacting, and are much quieter in noise generation and are more suitable in situations where any kind of EMI is undesirable. Electromechanical relays are usually less expensive than solid state ones, and are easier to construct, and are thus appealing when cost is a driving factor but switching speed is not.
The Solid State Relays (SSRs) Range of When to Use
In systems that require high speed high frequency switching solid-state relays are the stronger alternative. SSRs can be of great use in applications like motor control, heating systems and lighting control in an industrial automation system, because they have fast switching times and wear, as they are caused by electromechanical relays being eliminated. SSRs are especially useful in areas subject to vibration, shock or temperature changes, where there is potential to use higher levels of such due to their absence of moving parts. In addition, SSRs are more likely to be the choice where electrical noise or electromagnetic interference (EMI) is susceptible, e.g., data center, high-tech factory, or sensitive control area. SSRs have improved durability and therefore are very suitable in the long term operations where little maintenance work is involved. SSRs are usually the most suitable especially where your system needs a particular performance that remains precise and reliable over the passage of time without incurring frequent replacements.
When to Choose Electromechanical Relays (EMRs)
Electromechanical relays are most appropriate in the systems in which the main factors to be considered include cost-effectiveness and simplicity. EMRs are an ideal find in case you are operating on a budget or do not have the stricter performance requirements. Electromechanical relays are comparatively inexpensive, interchangeable and easily installed; thus, applications such as motor starters, elementary alarms and control circuits are all possible areas of application. Another application in which they excel is in low-frequency, low-cycle applications where the switching frequency is only relatively low and wear and tear due to mechanical movement is not critical. Moreover, in case your system does not need the fast functions of an SSR or is less concerned about the electrical noise, you would find EMRs fit your application substantially. EMRs may not match the durability of SSRs but their high current switching capability and low initial cost may make them the correct solution to simpler, less critical systems.
Conclusion
A decision between using solid-state relay and electromechanical relay mostly depends on the system needs and demands. Solid-state relays are most suitable in situations where there is need of fast and high frequency switching, low maintenance schedule and where high reliability and durability is involved. Electromechanical relays are more suited, alternately, to less demanding applications where cost is a more relevant factor, and high-speed switching is unnecessary. Knowing the specific advantages and the limitations of each type, you better can decide on what relay can optimize the operation of your automation systems.
When dealing with viable manufacturers of electrical relay, you are assured of getting the right industrial electrical parts that fit your application. The right relay type you choose to use will not only ensure that your system has an improved efficiency and reliability but it will also save you maddening maintenance costs and downtimes as well as electrical casualties in the long run. Through good planning considerations of the factors such as speed, durability, cost, and the requirements of the application needs in consideration, you can be able to decide on the kind of relay that will serve optimally in your industrial automation needs.
