SAX - Functional Principle
The Secu Access (SAX) performs an automatic operating sequence to prevent false trips and simplify the task of testing. The intelligence is built into the plug: different length fingers create the sequence and fixed current shorting bars provide safe and reliabe make-before-break current shorting.
Figure 1
One SAX terminal/test block contains modular units (or “poles”) each allocated to a current, voltage, signal or trip circuit. Each circuit is connected through the block via two silver-coated copper contacts, pressed securely together by two pressure springs to create a highly conductive electrical connection.
Figure 2
To open these modular poles, a high-quality insulation plastic finger of a SecuControl Test Probe or Plug (STP) is inserted between the copper contacts (Note: STP Test Plugs are also compatible with the flush-mounted ITS). CT circuits are safely and automatically shorted, and test plugs provide properly sequenced entry and the interface for secondary injection testing.
When the probe or plug is removed, the springs naturally force the contacts back together, returning the circuit to its normally-closed position and eliminating the risk of accidents from improperly closed circuits. At a glance, one can easily see whether a pole is opened if a plug or probe is inserted in the block.
Automatic Operating Sequence
Upon insertion, the SecuControl SAX performs a 4 step automatic operating sequence. When the Test Plug is inserted, the trip circuits are first opened by the longer pins, followed by the shorter pins that automatically short the CT circuits via the internal shorting bridge. Voltage circuits are then redirected through the plug and test procedures are ready to begin. When the plug is withdrawn, the circuits are restored in the reverse order beginning with step 4 of the insertion sequence.
The automatic operating sequence simplifies the job of the technician. Proper isolation and restoration of the device being tested is achieved every time. Costly false trips and errors in CT short-circuiting are no longer a concern with the SAX.