A relay is simply an electrical switch but instead of being operated by someone to turn it on or off, it is operated by another electrical circuit. So, essentially a relay is an electrically operated switch. We typically see a relay is used when we need to control a switch that has high voltage or high current passing through it and it is much safer to operate it by another switch instead of operating it directly. By using relays, you can significantly increase the operational safety of the circuit.
Using relays also allows you to control several devices by a single switch instead of using several different large switches. Relays can also be combined with timers and logic circuits which, makes them more suitable for automation.
You may find relays in electrical devices that operate several other electrical devices such as motors, fans, blowers, etc. In industrial applications, they are commonly used in control panels for various tasks such as controlling a motor or valve or other electrical devices in the system.
A relay consists of two different circuits that work in tandem to turn a switch on or off. The first circuit drives an electromagnet and creates a magnetic field. The second circuit contains a set of contacts and a separate power source. The magnetic field pulls the contact from the other circuit and closes it which allows the current to pass through the contacts, which allows the load to become energized. When the coil is de-energized, the magnetic field is lost which lets the contact be pushed back into its original open state, which de-energizes the circuit.
Protective relays monitor critical operational parameters and initiate an emergency shutdown when they detect out-of-limit conditions. Protective relays detect abnormal conditions and shut down the equipment to save the equipment and related systems. However, if the relays operate incorrectly then it will lead to the shut down of the equipment without any reason.
Electrical protective relays are calibrated with settings that are determined during the system design phase. Initial settings are provided when relays are initially installed. However, electrical systems change as a new generation of equipment is added or it replaces the obsolete equipment. This may mean that those relay settings become no longer correct and these incorrect relay settings can be hazardous to the personnel and the equipment.
There is a large number of relay types, and it is quite possible to find a mix of several relay types and functions in the same system that needs to be tested with the relay test set. Therefore the way to test a relay will depend on many different considerations based on the type and function of the relay.
Modern relay test sets are capable of testing all types of single-phase equipment, over-current, under & overvoltage, leakage current, power, differential, and directional relays, etc. These test sets have a current transformer, auto variable transformers, contactors, time interval meter, etc. all housed in one box. Suitable switches are provided for the selection of current, voltage ranges, and selection of relay type.
As electronic components age, they drift from their original specifications. A measuring device will lose its ability to measure accurately. Therefore, it should be calibrated to ensure that it works correctly within the expected ranges.
Calibration is extremely important because it ensures that your measurements are accurate as they are the basis for the quality and safety of the products to be tested. Calibration saves money by detecting potential manufacturing errors before they occur. Issues can be proactively resolved and corrected during the normal maintenance period instead of repairs in forced shutdowns.
If you are performing a measurement where the results will make a critical decision such as a safety test, you should get your equipment calibrated. This is especially important if you want your results to correlate with international standards.
The cost of not calibrating means higher production cost, false acceptance and false rejection of products, and increased plant shutdowns. Personal injury and unnecessary legal costs are some of the big risks of not calibrating.
e2b calibration can repair and calibrate your Relay Test Sets. We are an ISO/IEC 17025 accredited calibration laboratory and have the necessary expertise to test and calibrate your test sets. Our verifiable services are unmatched in the industry. We are registered with ANAB. We are also ANSI/NCSL Z540-1-1994 certified. We have the NIST Traceable Wide scope of ISO/IEC 17025 accreditation. Contact e2b calibration for all your equipment calibration needs.