General purpose relays are mostly used as a control circuit or relay sequence for controlling the circuits of automated machines deployed at production sites.  In addition, they are also used for other control systems such as lighting, air conditioning and water treatment of buildings.

Benefits of General-Purpose Relays

They are economical and result in reduced system costs on control panels with space constraints. Their small profile and side-by-side DIN-rail mounting result in a simplified installation and wiring process. General purpose relays such as the Macromatic are colour-coded and enable quick testing along with troubleshooting of the control logic circuits. Macromatic relays come with LED lights to allow visual confirmation once the relay has been energized. Since they come with transparent covers, they allow for easy monitoring of operation and contacts condition.

Types of General-Purpose Relays

  • Control Panel Type- In such scenario’s, relays with 1 to 4 poles are used for relay sequences or I/O applications.
  • Built-in Type– These relays can carry current up to 40 A and are used in building devices.
  • Work Saving Type– They are mainly used for I/O applications for programmable controls in downsizing and saving work scenarios.
  • Special Operating Type– They are used for specific applications, like in the case of alternative operation and for stepping operation of pumps.

Application of General Purpose Relays

  • Relay sequences: These are used to construct a control circuit by a combination of four primary relays
  • I/O Relays: They are used for relaying a load of a controller such as a solenoid valve, etc.
  • Building Automation: Used to automated lighting, and air-conditioning units, etc.
  • Infrastructure Support: Used in applications such as water supply support, information, etc.
  • Plant Automation: Used in automation of production plants such as Electricity, Steel, Shell Gas, etc.
  • Factory Automation: Used in machines that are used for manufacturing automobiles, semiconductors, and chemicals, etc.

Comparison Between General Purpose Relays and Transistors

Transistors are just like relays and can also be used as an electrically operated switch. In case there is a need to switch small DC current at low voltage, then using a transistor can be a better option. However, on the downside, transistors are unable to switch AC or high voltages and aren’t a great choice when it comes to switching large currents. This is where a relay comes into the picture. Now that you have a basic understanding of general purpose relays and transistors let’s look at a few advantages and disadvantages of relays.

Advantages of Relays

  • They can switch to AC and DC, while transistors can only switch DC.
  • They are capable of switching to high voltages, while transistors cannot.
  • They are a better choice for switching large currents (> 5A).
  • They are capable of switching many contacts at once.
  • They are cost-effective

Disadvantages of relays

  • They are bulkier compared to transistors for switching small currents.
  • They are unable to switch rapidly, while transistors can switch many times per second.
  • They use more power due to the current flowing through their coil.
  • They require more current than many chips can handle; therefore, a low power transistor may be required to switch the current for the relay’s coil.

General purpose relays are versatile and play a crucial role across a range of industries, and therefore, industries only go for high-quality relays that can get the job done efficiently. Partnering with a reputed electrical company can help you set up a general purpose relay for your industry quickly and in a cost-effective manner.

Leave a Reply