DSE DSE331 - Breaker Scheme B; Check Synchronising Is Disabled; Load Shed Input; Timing Diagram

Operation
25
6.4.5 BREAKER SCHEME B
Breaker Scheme B is intended only for use with certain designs of transfer switch. If you are using contactors, you
MUST select Breaker Scheme A.
6.4.5.1 CHECK SYNCHRONISING IS DISABLED
6.4.5.1.1 TRANSFERRING TO S2
To open S2 breaker the Open S1 output energises, it then de-energises when the S1 Closed Auxiliary indicates it
has successfully opened, or after 1s whichever occurs first.
When the ‘S1 Closed Auxiliary’ indicates the mains breaker has opened, the transfer timer begins.
When the transfer timer expires, the module attempts to close S2 breaker by energising the Open S1 and Close
S2 outputs simultaneously, it then de-energises these outputs when the S2 Closed Auxiliary input indicates it has
successfully closed, or after 1s whichever occurs first.
6.4.5.1.2 TRANSFERRING TO S1
To open S1 breaker the Open S2 output energises, it then de-energises when the S2 Closed Auxiliary indicates it
has successfully opened, or after 1s whichever occurs first.
When the ‘S2 Closed Auxiliary’ indicates S2 breaker has opened, the transfer timer begins.
When the transfer timer expires, the module attempts to close S1 breaker by energising the Open S2 and Close
S2 outputs simultaneously, it then de-energises these outputs when S1 Closed Auxiliary input indicates it has
successfully closed, or after 1s whichever occurs first
6.4.5.1.3 LOAD SHED INPUT
When the Load Shed input is activated while the generator is closed the Open S2 output energises, it then de-
energises when the S2 Closed Auxiliary input indicates that it has successfully opened, or after 1s whichever
occurs first.
When the Load Shed input is activated while the mains is closed the Open S1 output energises, it then de-
energises when the S1 Closed Auxiliary input indicates that it has successfully opened, or after 1s whichever
occurs first.
When the Load shed input is de-energised the load will be returned to the supply that was disconnected, providing
that supply is healthy.
6.4.5.1.4 TIMING DIAGRAM
Open S1
Close S2
Close S1
Open S2
Non-Sync Transfer Time Non-Sync Transfer
Time
S2 has closed
S1 has closed
S1 has opened
S2 has opened