Circuit breaker analyzer

Data records

• Timing can be done with both sides of the breaker grounded; the analyzer then senses contact operation by a dynamic capacitance measurement across the grounded contacts rather than by a voltage across open contacts, which removes the hazard of induced voltage in high-voltage substations and makes gas-insulated switchgear testable without altering its connections. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.both-sides-grounded
• The trip and close coil currents are recorded against time: the current rises, drops when the armature begins to move and releases the latch, rises again when the armature reaches its end stop and is cut when the auxiliary contact opens, so a change in the trace points to latch, lubrication or control-voltage problems. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.coil-current-signature
• The analyzer records the change of state of the main contacts, resistor contacts and auxiliary contacts against time during close, open, close-open, open-close and open-close-open operations, and the measured times are compared with the manufacturer's specification or a factory test report. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.contact-timing
• Dynamic resistance measurement injects a direct current through the main contacts while the breaker operates and plots resistance against time; when motion is recorded at the same time, the step between main-contact and arcing-contact resistance gives the remaining length of the arcing contact in a sulfur hexafluoride puffer breaker without dismantling it. Source: Megger application page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.dynamic-resistance
• A first-trip test is made with clamp-on current sensors on the coil circuit while the breaker is still in service and has not operated for a long time; the coil current, the control voltage and the instant at which the current is extinguished in each of the three phases are recorded on that first operation, which is the one most likely to reveal a lubrication problem. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.first-trip-test
• The opening velocity is the most critical travel parameter because the interrupter has to move at its design speed to build up the stream of air, oil or gas that cools the arc enough for the current to be interrupted at the following current zero; the analyzer calculates velocity between two points chosen on the motion curve, most commonly referenced to contact separation. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.opening-velocity
• Timing across the three poles reports the pole spread, or simultaneity between phases, and the analyzer also times several breaks per phase so that the contacts of a multi-break interrupter are checked against each other as well as against the specification. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.pole-spread
• The analyzer stores test records and test plans internally and on a removable drive, and its built-in printer prints the contact travel waveforms together with tabulated results. Source: Doble product page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.records-and-reports
• Contact travel is captured by a linear or rotary transducer attached to the moving part of the operating mechanism or interrupter; the analyzer presents motion as a curve of distance against time and derives stroke, total travel, overtravel, rebound, contact wipe and average and instantaneous velocity from it. Source: Megger application page, web page edition. Verified 2026-10-27. Record instr.circuit-breaker-analyzer.travel-transducer