Video: BPM – Technical guide

Video transcript

What is inside the chassis, what gets connected to the breaker, and the settings that decide whether any of it works. Start with the box. It is not a fixed instrument: it is a card cage. The cards are chosen for the breaker being monitored, and every field connection lands on a plug-in terminal block, so a card can be pulled for testing without touching a single wire. These are the cards. Reading left to right, the processor and the communications, then the general purpose input and output, then the two cards that do the real work:

the current inputs that watch the coils and the poles, and the alternating current inputs that watch the motor. Now what is actually wired to the breaker. A transducer on each coil, 3 current transformers on the poles, the motor volts and amps, the auxiliary contacts and the gas sensors. That is the whole installation. The sensors themselves are small and specific. The coil currents need a direct current transducer,

because a coil current is direct current and an ordinary current transformer cannot see it. The pole currents use split core units that clip around an existing conductor. Before setting anything, understand what you are trying to record. This is the current in a trip coil during one operation, and each feature is a mechanical event you can put a name to. Now the setting that matters more than any other. The monitor records nothing until it is triggered, and it leaves the factory with triggering switched off.

If you do not configure it, and prove it, the monitor will sit there for years recording nothing at all. Once triggered, the recording takes care of itself, and it always includes the two cycles before the trigger, so the start of the event is never lost. And this is what you are looking for. The grey line is the breaker when it was healthy. The red one is the same breaker today. Nothing has failed, and no alarm from a conventional scheme would have moved.

But it is slower, and it will keep getting slower. From every capture the monitor takes the same set of numbers, defined the same way each time, which is what makes one operation comparable with another. The motor is watched separately, and one of its alarms is cleverer than it first looks: if the breaker changed position but the motor never ran, something in the mechanism moved without being driven. Setting it up follows a fixed order, and the order matters:

the breaker type has to be chosen before anything else appears, because it decides which software modules load. And proving them is not optional. Operate the breaker, look at the waveform that came back, and check that the levels are what you expected. A monitor that is not triggering looks exactly like a breaker with nothing wrong. Getting the data out uses two separate paths. Ethernet, on copper or on fibre,

sharing one address so both connectors reach the same processor. And two serial ports, each isolated from the other, one of which usually carries the gas sensors. Finally the alarms and the reports, which is where the monitoring turns into something a maintenance department can act on. And the little that the monitor itself asks of you. Breaker monitoring, from Amperis.