Under current relay
Voltage sensing relay
Latching relay
Current sensing relay
Impulse relay
Dry reed relay
Thermal relay
Free relay
placing asbestos between the contacts
providing a shading coil near the tip of the magnetic field
cleaning the dirty particles over the coil and contacts
applying varnish over the coil core
eliminate the chattering noise in relay
protect the equipment from fluctuating voltage
provide the gap between the layers of magnetic core
increase the strength of the magnetic field
No effect, remain in same operation
Chattering noise will be more
It will draw enormous current, lead to burn the relay
It will operate in high speed