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Sr. No.	Specification	Value
1	Trigger condition	Peak Ground Acceleration (PGA) on any Axis. Settable range: 0.01g to 0.99g
2	Features	Fail safe design, manual self-test
3	3 dB Cut-off frequency on each axis	13.5 Hz
4	Output	Two numbers of Potential free 2 form C (DPDT) relays with contact rating of 1.0A at 24VDC – (Earth quake relay and Status relay)
5	Battery	Lithium-ion battery. 3700mAH X2(10Hrs Backup) Automatic charging during main power operation
6	Calibration	Tilt table can be used for verifying the calibration
7	Enclosure and mounting	Rugged IP 66, 4 M8 mounting holes for easy installation
8	Operating Temperature	0-70 Degree Celsius
9	MI/EMC	Designed to meet IEC-61000-4.2, 4.3, 4.4 ,4.5,4.6 and 4.8 (to be tested)
10	MTTF	>80 Years (As per MIL-HDBK-217PLUS)

1. Primarily designed for Automatic Reactor Trip System (ASTS).
2. Can also be used for Industrial Processes, Chemical Processes, Gas valves, Hazardous Systems, Solenoids, Elevators, Walkways, Electronic gates and door.

BARC Seismic Switch (Analog) is useful in accurate detections of strong earthquakes. Thus it provides safe shut down options for Industrial Processes, Chemical Processes, Gas Valves, Hazardous Systems, Solenoids, Elevators, walkways, Electronic gates and doors etc.

Seismic Switch (Analog) monitors its attachment point to detect seismic (earthquake) motions in all 3 mutually perpendicular axes(X, Y and Z). It monitors acceleration in all the three axes and triggers on detection of Peak Ground Acceleration (PGA) on any axis. Trimpots are provided for easy threshold settings. The unit provides two numbers of 2 Form C (DPDT) isolated relay contacts. Relay 1 is Earthquake relay and Relay 2 Status relay. Earthquake relay is in energised state during normal operation and de-energises on complete loss of power (including battery). This ensures ‘fail safe’ operation of the system. On-line testability is another important feature in this system which enables the user to manually initiate the self-diagnostics of the system without removing it from the installation. Battery backup provides for 10 hrs of power. IP66 enclosure makes the system robust for all environments.

SPECIFICATIONS

Table 1 : Specifications of Analog Seismic Switch.

Sr. No.	Specification	Value
1	Actuation acceleration range	0.01 to 0.99 g with a set point accuracy of 0.01g. The set point can be fixed
2	3 dB Cut-off frequency on each axis	13.5 Hz
3	Output	Two numbers of Potential free form C relays with contact rating of 1.0A at 24VDC. Earth quake relay and status relay. Relay actuation conditions is given in the table 1.
4	Closure Timing	On seismic event, relay will remain actuated for user settable time period. Typically set for 5 Seconds.
5	Battery	Lithium-ion battery. 3700mAH X 2
6	Battery Charging	Battery will be charging while system is operated on mains power. Automatic switching to battery during power outage
7	Enclosure	IP 66
8	Operating Temperature	0-70 Degree Celsius
9	Calibration	Tilt table can be used for verifying the calibration
10	EMI/EMC	Will be done as per NPCIL requirement
11	Functional verification on Shake Table	Yes

Table 2 : Various Triggering conditions of Analog Seismic Switch.

Sr. No.	Triggering Conditions	Earth quake Relay (relay-1)	Status relay (relay-2)
1	Earth quake	Triggers. Resumes original position after 5 seconds if earthquake signal has gone.	Relay coil is in De-Energised State. No change of contact.
2	Complete power loss including battery	Triggers and resumes only when power restores	Relay coil is in De-Energised State. No change of contact.
3	Manual confidence test (By pressing a remote push button)	Actuates. Resumes original position after 5 seconds of release of push button.	Relays get Energised as long as the push button is pressed if confidence test passes.
4	Working on battery	No actuation. It will actuate on detection of earth quake.	Relay coil is in De-Energised State. No change of contact.

1. Nuclear Reactor Applications:

   After Fukushima incident it has become a regulatory requirement to have Automatic Reactor Trip System (ASTS) on detection of earthquake. This is designed to scram the reactor upon the occurrence of a seismic event, before turbine trip or other conditions resulting from the seismic disturbance could cause a scram. The earlier scram could give a lead time between 5 to 20 seconds. The lead time could provide resulting benefits such as reduced loads during the seismic event and, therefore, fewer burdens on the plant systems. It may also reduce the likelihood of a LOCA or severe transient after a seismic event. ASTS comes under classification as safety Class IA system (reactor protection) and has to meet the relevant standard requirements such as on-line testability, fail safe and other qualification requirements. Since systems that are available in the market do not meet these requirements, BARC has developed fully functional prototype designs of the Seismic Switch.

2. Industrial Applications:

   Chemical plants, Oil and Gas processes, hazardous areas, etc need to take safe actions in the event of an earthquake. Seismic Switches can be used to trigger these safe procedures to save lives and machinery.

3. Transport and Building Applications:

Elevators can be brought to the nearest floor and the doors can be made open. Automated gates of buildings can be opened. People in the vicinity can be alarmed to take shelter etc.

FACILITIES REQUIRED / INFRASTRUCTURE REQUIREMENT FOR COMMERCIAL PRODUCTION

1. Standard Electronics PCB assembly and testing instruments such as Soldering station, multi-meters and an Oscilloscope. An Instrumentation/Electronics/ Electrical engineer who is familiar various qualification procedures of this system.