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The Circuit Breaker Timer is a microprocessor-controlled timer designed to test electrical-utility circuit breakers. The CBT can also time contact operations of any switching device-e.g., switching relays, remotely controlled contactors, etc.) It contains 3 independent timers for the simultaneous timing of each set of contacts in three-phase breakers. The CBT fully analyzes the timing of breaker contact operation: OPEN, CLOSE, OPEN-CLOSE, and CLOSE-OPEN. It's field-portable, very rugged, and is easily operated by first-time users with little training. It features a 16-key pushbutton pad for entering breaker test ID and control function. A 4-line by 20-character backlighted LCD displays control menus, and measured test results. Test results can be printed on a built-in 2.5inch-wide thermal printer. Operation requires little more than connecting the cables of the CBT to utility breaker contacts, selecting the desired test options and enabling the test results to be stored in a non-volatile memory. Operations do not require any conversion calculation, written note, or detailed list of steps to remember (thus, greatly reducing any chance of error by the operator). The CBT stores up to 128 timing (test shot) records in FLASH EEPROM memory. Stored timing-measurements and related data can be displayed and printed in the field or stored for later review, analysis, or printing. A RS-232C serial interface port also provides for computer interface and diagnostic test.Functional DescriptionCBT's operation (a timing shot) is started by an input trigger (e.g., a breaker's initiating control voltage), which starts all 3timers at the same instant. Each timer independently stops after detecting each contact transition. Besides measuring contact time each timer will also measure contact bounce time. The timing results display in both milliseconds and cycles. The cycle display is selectable between 50Hz or 60Hz.The CBT can be interfaced (via an RS-232C interface port) with an IBM-compatible PC. A software package supplied with the CBT allows the user to retrieve the test data stored in the CBT Flash EEPROM.Before first-time operation of the CBT, Step-by-Step Operating Procedures Flow Diagram should be reviewed. This figure shows the logic-flow branching of multiple test options. The device operation is simple, requiring little more than selecting choices from display menus and responding to the displayed prompts.Preliminary ProcedureTurn on device power; press "1" on the rocker switch. Observe that after configuration data displays briefly, the START-UP MENU displays (selections for "1. RUN TEST,""2. SETUP," and "3. CABLE TEST").Cable Test ProcedureThe purpose of the Cable Test is to quickly check the test leads and breaker contacts for continuity at each of the 3 phase contacts. For example, a close test should begin with all contacts open; conversely an open test should begin with all three contacts closed-the closed condition also checks continuity of the test leads for opens or erroneousThis content has been taken from http://www.ideamarketers.com/?articleid=3319181&CFID=190800580&CFTOKEN=71143508
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