LITERATURE REVIEW (FYP 1)

JOURNAL 3


RELAY MODULE

Advantages: 

• Electromagnetic relays have fast operation and fast reset. 
• They can be used for both ac and dc systems for protection of ac and dc equipment. 
• Electromagnetic relays operating speeds which has the ability to operate in milliseconds are also can be possible. 
• They have the properties such as simple, robust, compact and most reliable. 
• These relays are almost instantaneous. Though instantaneous the operating time of the relay varies with the current. With extra arrangements like dashpot, copper rings etc. slow operating times and reset can be possible. 

Disadvantages: 

• High burden level instrument transformers are required (CTs and PTs of high burden is required for operating the electromagnetic relays compared to static relays). 
• The directional feature is absent in electromagnetic relays. 
• Requires periodic maintenance and testing unlike static relays. 
• Relay operation can be affected due to ageing of the components and dust, pollution resulting in spurious trips. 
• Operation speed for an electromagnetic relays is limited by the mechanical inertia of the component. 

Applications: 

• Electromagnetic relays are employed for the protection of various ac and dc equipment. 
• The over/under current and voltage protection of various ac and dc equipment. 
• For differential protection. 
• Used as auxiliary relays in the contact systems of protective relay schemes.

Credit to : Prajapati Dipali, K., Raj Roshani, D., Patel Komal, C., & Hilali Marhaba, A. ( 2014). Automatic Gate Opening System For Vehicles With RFID or Password.