Lockout Relays are also referred to by many names including master trip relays or as defined by the American National Standards Institute as ANSI code 86.
Their main use is to improve the safety and dependability by regulating the functioning of circuit breakers in the case of specific conditions.
Lockout relays can be used to perform functions such as automatic locking for a period of time that is pre-programmed or for an amount of time that is determined by a fault condition Like any other relay, this kind of relay has various uses which include:
Fault Isolation: Contactor lockout relays are specifically provided for disabling and keeping specific protection zones off line when a fault is detected. This reduces the back feeding of equipment until fault has been rectified and safety check done.
Intermediary Role: They act as mediators between one or more protection relays and/or control devices. This enables them to perform multiple operations at once as far as breaker trips, alarms and data readability are concerned and thus reduce the complexity of the control circuit and increase operational reliability.
Manual Reset Requirement: Lockout relays are those in which the output contacts are latched once the relay is energised, it can only be de energised by manual operation. This guarantees that the operators ensure that the fault condition is no longer present before making the system active again and in the process avoiding equipment damage or creation of safety risks.
Enhanced Safety: These relays assure that a circuit cannot be closed while being locked out and as such help guard both personnel and equipment from the risks inherent in re-energization at the time of maintenance or other faults. This is important in order to avoid occurrence of accidents or malpractice in the operations of industries.
Integration with SCADA Systems: SCADA Lockout relays may be incorporated into SCADA systems for monitoring and operation from a distance. It also increases control of the general functioning to hasten response to occurrences of electrical faults.