11 Questions
What is the primary function of relays in protection systems?
To detect faults and trip directly
What type of relay is commonly used as an output relay for many solid-state protective relays?
Telephone relay
What is the advantage of high-dropout models of solenoid type relays?
They have a lower dropout value
What is the purpose of taps or other means in AC type relays?
To change the pickup value
What happens when the current or voltage drops to the order of 60% of the pickup value in some relays?
The relay drops out
What type of relay is used as a seal-in contact switch in DC applications?
Solenoid relay
What is the percentage of the pickup value at which the fault detectors will reset?
90%
What is the primary function of the moving cup or cylinder in the AC induction cup or induction cylinder unit?
To rotate the contacts and spring to provide reset
What type of fault detectors are recommended in general?
High-dropout type
What happens when the fluxes of coils one and two are in phase?
No rotational torque exists
What is the typical time of operation of the instantaneous overcurrent unit?
16-20 ms
Learn about the different types of relays used in protection systems, including clapper, solenoid, and induction relays. Discover their applications and how they work.
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