Electromechanical device containing a coil and set of contacts.

Relay contacts can be in one of two states:

Relays may be operated electricly, using pneumatics, or a combination of both.


The load impedance imposed by a relay on its source, expressed in ohms and phase angle at specified conditions.

Modern solid state protective relays have very small burdens, while some older electromechanical relays had significant burdens, requiring the use of high output instrument transformers to drive them.

See also: Armature, Burden, Closing Time, Control Relay, Definite Time Relay, Inverse Time Relay, Protective Relay, Seal-in Relay, Thermal Relay, Trip-Free Relay.

Previous PageView links to and from this pageNext Page

Subjects: Electrical Engineering Electronics