What are the common uses of electromagnetic relays

An electromagnetic relay is a type of electronic switch. It functions when a predetermined impedance or reactance is exceeded. This allows it to convert a small electrical current into a larger one. These switches can be found in a variety of shapes and sizes. 
Relays are useful in monitoring important equipment and power parameters. They are also effective in detecting power outages, interruptions, and increased contact transfer resistance. Another common use for a relay is to monitor a control voltage. This is particularly useful in industrial settings. A voltage monitoring relay can also detect if the relay is experiencing a failure, such as a faulty control or a blown fuse. However, there are some limitations to using these relays.
An electromagnetic relay is made up of a multi-turn coil wound around an iron core. Energisation of the coil makes the iron core magnetized and attracts the iron armature. This armature then pivots and operates contacts. The magnetic field from the second circuit energizes the first circuit, causing the contact to open or close. In some cases, an electromagnetic relay can be positioned far from its control source, allowing the device to be located anywhere on a remote site.
An electromagnetic relay also has two types of contacts. One is normally open and the other is normally closed. The latter is used for relays with multiple contacts and is typically called a balanced beam type. One type features a fixed beam and an electromagnet. The electromagnet consists of two coils, one of which is energized by a voltage and the other by a current. When the two coils are opposite, the operating force of the relay energizes the coil and causes it to tilt. The tilting beam closes the contact and actuates the circuit breaker.

90A Lead wire vertical installation integrated Magnetic Latching relay