How to select Miniature Relays for your application?
Miniature relays are a key component of many electronic, automation systems, especially where space saving or signal control is of paramount importance. However, selecting the right relay for a particular application is a process that requires consideration of many factors that determine the reliability and efficiency of the overall system. In this material, we will discuss what to look for when selecting miniature relays to ensure optimal system performance
How important are relay load voltage and current?
The primary criterion for selecting a miniature relay is its compatibility with the voltage and current requirements of the application. The voltage supplying the relay coil and the current to be switched by the contacts must be known exactly. The relay must be selected so that it is capable of operating at the specified load current, specified coil voltage, contact voltage and other parameters specified in the technical specifications. Incorrect selection of these parameters may result in the component overheating or being damaged.
A special relay with high contact voltage is the miniature RM85 relay for switching higher voltages - its maximum contact voltage is up to 480 V AC.
What should be the number and type of contacts in the relay?
Another important aspect is the number and type of contacts. Miniature relays come with a variety of contact configurations - they can have one or more sets of contacts, and differ in whether they are normally open (NO), normally closed (NC) or changeover (CO) - it is worth noting at this point the basic relays that come in both changeover and (NO) contacts, which are closed contacts. Examples are the RM84 and RM85 relay. Depending on the function to be performed by the relay, the choice of the appropriate contact arrangement is crucial.
Relay operating temperature and protection class
The operating conditions of the application can significantly affect the choice of relay. If the device will be operating in harsh conditions, such as high temperatures, humidity or a lot of dust, it is worth choosing a relay with a suitable protection class (e.g. IP). In applications where vibration or shock may occur, it is also important to pay attention to the relay's resistance to these factors. A very interesting solution is a relay that can withstand an ambient temperature up to 105 °C Miniature Relays RM85 105 °C sensitive
Switching frequency
Relays also differ in terms of mechanical and electrical durability, i.e. the number of cycles they can withstand. If the application requires frequent switching, it is important that the relay has a high life expectancy and is suitable for such conditions. Relays with longer lifetimes are more reliable and need to be replaced less often, which can reduce system maintenance costs.
Size and shape of the relay
One of the main advantages of miniature relays is their small size, making them an ideal choice for applications where space saving is crucial. Before purchasing a relay, make sure that its size and shape will be suitable for the space in which it will be installed. However, miniaturisation should not come at the expense of performance - the relay must be able to meet the requirements of the application.
Insulation and surge resistance
Depending on the application, the level of isolation and surge resistance can also be an important factor. Some relays offer high noise immunity and galvanic isolation, which is important in applications with high potential differences or sensitive to electrical interference. If a high inrush current relay is required, we recommend using the RM85 inrush relay with a inrush current of 80A. Miniature relays RM85 inrush
Relay coil requirements
A final, but equally important factor, is the type of relay coil. Coils can be either direct current (DC) or alternating current (AC). It is very helpful to check the status of the contacts, and to quickly distinguish the type of control circuit, to use a transparent relay cover - orange for the AC coil and blue for the DC coil. Depending on the type of coil, relays have different parameters. It is worth paying attention to the operating voltage of the coil, its resistance and the switching current. Improper selection of the coil may lead to incorrect operation of the relay, which in turn affects the functioning of the entire system.
Some applications require the use of a relay with a sensitive coil - in such cases, the perfect solution is a miniature relays RM87 sensitive with a load capacity of 10 A and a maximum current of 20 A.
There are relays for printed circuits with a special coil lead. These are RM85 faston relays for flat connector slide-in connections with two possible arrangements: vertical (V) and horizontal (H).
The selection of miniature relays for an application requires consideration of many technical factors, such as voltage, current, number and configuration of contacts, as well as environmental and mechanical conditions. It is important that each of these aspects is properly matched to the application requirements to ensure reliability and long system life. By considering these factors, you can be sure that your relay selection will be optimal and that the entire installation will operate smoothly and without failure. The relays described above are manufactured with great care as can be seen in the video "How is a miniature relay made?"