• Dry-contact inputs: 3 channels
• Trigger input voltage open/close: 30 ¬ 300 V, DC or peak AC
• Breaker operations: Open, Close, Open-Close, Close-Open
• Timing resolution: ±0.1 millisecond
• Detect Main & Insertion Resistor Contacts on same input
• USB computer interface
• USB Flash drive interface (Flash drive not included)
• Store 128 test records internally
• Initiate Breaker Operation
• Built-in 2.5" wide Thermal Printer
• Rugged "QWERTY" style membrane keypad

The CT-3500 S2 is Vanguard’s second generation, stand-alone, digital, microprocessorcontrolled, circuit-breaker timer. It measures the elapsed time from the instant a breaker coil is energized to the instant of opening or closing of a circuit-breaker’s dry contacts. In addition to timing a breaker’s contact response time, the CT-3500 S2 can also time relays or other switching functions that use an initiating trigger voltage (30- 300 Volts DC or AC). The timer-triggering voltage starts three independent electronic timers. Each timer is individually stopped by its respective dry-contact closing or opening.

The CT-3500 can fully analyze the timing of all circuit breaker operations (Open, Close, Open – Close, and Close – Open). Timing results are displayed in milli-seconds and cycles on the unit’s back-lit LCD screen and can be printed on the built-in 2.5-inch wide thermal printer.

Contact Timing Inputs

The CT-3500 S2 features three dry-contact, timer-channel monitoring inputs. The dry-contact

channel power supply is fuse-protected. All inputs are shunted to ground until the instant a test is initiated. All contact timing inputs are protected against static discharge. A contact self-test cable-mode is also available for testing cables or connections to the breaker.

Internal Test Record Storage

The CT-3500 S2 can store up to 128 test records in Flash EEPROM. Test records can be retrieved and printed on the built-in thermal printer, or they can be transferred to a PC via the unit’s USB interface. The USB interface can also be used for diagnostic testing and for updating firmware.

The CT-3500 S2 also features a USB Flash drive interface that can be used to store test records on an external USB Flash drive.

A Windows®-based Circuit Breaker Analysis application is provided with each unit and can be

used to transfer test records to a PC. Test records can also be reviewed, printed or exported in Excel, PDF, and XML formats for further analysis

User Interface

The CT-3500 S2 features a back-lit LCD screen (128 x 64 pixels) that is viewable in both bright sunlight and low-light levels. A rugged, 44-key, "QWERTY" membrane keypad is used to control the unit and input data. The unit's built-in 2.5- inch wide thermal printer can be used to print test reports.