Digital Circuit Breaker Analyzer CT-8000

The CT-8000 is Amperis fifth generation, stand-alone, microprocessor-driven EHV circuit-breaker analyzer. This easy to use analyzer is available in models with either 3 (CT-8000-3) or 6 (CT-8000-6) dry-contact inputs. Both models feature three digital travel transducer input channels. The CT-8000 can operate either in Time-Travel analyzer mode or in Quick-Shot mode (for on-line timing). Quick-Shot Mode

In Quick-Shot mode, the CT-8000 captures the breaker's trip or close time, the trip/close-coil current "fingerprint," and the battery supply voltage while the breaker is still in service. The trip/close time is derived from the time of trip, or close-coil initiation, to the breaker's bushing current-break-or-make as detected by an AC clamp-on current sensing probe.

With a simple connection, the Quick-Shot mode can detect a breaker's operating conditions with little or no down time. In Quick-Shot mode, the first trip operation time of the breaker is captured. If a breaker has been in service for a long period of time and sitting in close position, the first trip time of the breaker may be slow possibly due to a sticky mechanism. The Quick-Shot mode is very useful in such cases because traditional breaker timing may not detect this condition since several operations may have occurred before the first timing test is conducted.

Conventional Time-Travel Analysis Mode

In Time-Travel mode, the CT-8000 can fully analyze a circuit-breaker's performance by testing the contact time, stroke, velocity, over-travel, and contact wipe. Contact-motion analysis can be performed for all breaker contact operations (Open, Close, Open – Close, Close – Open, and Open – Close – Open). The CT- 8000 S2's timing window is selectable between 1-second, 10-second, or 20-second periods. The 10-second and 20-second timing windows are ideal for timing long duration events such as circuit-switcher contact testing.

Contact Timing Inputs

Dry-contact input channels are used for timing breaker contacts. Each contact input channel can detect main contact and insertion-resistor contact times in milliseconds and cycles.

Voltage Monitoring Inputs

One analog voltage input channel, designated as V1, is dedicated to monitoring a circuit- breaker's DC power supply or coil voltage (0 – 255 volts, DC or peak AC). A second voltage input channel, designated as V2, is dedicated to detecting the voltage on/off status (presence or absence) of an A/B switch.

Trip/Close Current Monitoring

A built-in Hall-effect current sensor records the Trip/Close current level and duration. The breaker's operate-coil current waveform duration (effectively, a performance "fingerprint" or "current profile") can be used as a diagnostic tool for analyzing a breaker's performance.

Breaker Stroke and Velocity

Three digital travel transducer channels are available on the CT-8000 for measuring circuit- breaker velocity, stroke, over-travel, and bounce-back. Unlike other transducer types, the digital transducer requires neither calibration nor setup. A breaker's contactvelocity is calculated based on the contact's travel distance over a period of time. A special feature is also available to "slow-close" test a breaker and obtain a test result report.

Dynamic Contact Resistance

Using a 200-ampere, built-in, DC power supply, the CT-8000 can also perform dynamic-resistance tests. One channel is available for performing a dynamic contact resistance test. The resistance measuring range is from 1 micro-ohm to 1,999 micro-ohms. Using this test, the contact resistance can be monitored during circuit-breaker operation. This important feature can help detect circuitbreaker contact erosion or other contact problems that cannot be detected in static resistance tests. The CT-8000 can also be used as a 200-ampere micro-ohmmeter to test circuit-breaker contact resistance and bus connections, or can be used for other applications where a low-resistance measurement is required.

Resistor Type Transducer Input

One resistor type input channel is also available on the CT-8000. This input channel allows the unit to measure circuit-breaker motion by directly interfacing with resistive type transducers. The transducer resistance ranges from 200 ohms to 10K Ohms.

Breaker Initiate Features

A built-in solid-state initiate device is used to operate a breaker from the CT-8000. The operational modes include Open, Close, Open – Close, Close – Open, and Open – Close – Open. Multiple operations, such as Open – Close and Open – Close – Open, can be initiated by using programmable delay time or by sensing a breaker's contact condition.

Internal Test Record Storage

The CT-8000 can store up to 150 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 RS-232C or USB interface.

Internal Breaker Test Plan Storage

The CT-8000 can store up to 99 circuit-breaker test plans. Test plans are comprised of all circuit-breaker performance specifications (stroke, velocity, and contact time). A test plan can be used to immediately test a circuit-breaker. A pass/fail report is then generated by comparing actual performance with the specifications in the stored test plan. Test plans can also be generated on a PC and transferred to the CT-8000 via the unit's RS-232C or USB interface.