If you've ever commissioned a switchgear panel, you know that a relay setting on paper means nothing until current actually flows. That's exactly why a primary injection test set matters. Unlike secondary injection, which only checks the trip unit, primary current injection pushes real load through the whole protection chain — the CT, the wiring, the connections and the breaker mechanism itself — so you find out how everything behaves together under a simulated fault.

The 1000BS Primary Current Injection Tester is our own answer to that job. We built it as a high-current generator (a "current riser") that outputs a smooth, continuously adjustable 0 to 1000A single-phase AC current, with a standard sine waveform, ripple under 0.3% and accuracy better than the 0.5 class. Thanks to a low-loss auto-regulator and a high-permeability core converter, it delivers big output power in a housing that's only 30%–70% the size and weight of comparable units — a real difference when you're carrying gear up to a substation platform.

What does that let you do on site? Quite a lot:

• Run circuit breaker trip-time testing across long-time, short-time and instantaneous settings

• Perform CT ratio tests and primary bus protection checks

• Calibrate thermal relays, motor protectors, contactors and air switches

• Read primary and secondary current directly on a 6½-digit large LCD, with a display-lock function for fast, repeatable readings

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The timing side is handled too. The 1000BS measures the operating time of the device under test from 0.0001s up to 9999.9999s at 0.0001s resolution, automatically identifies normally-open and normally-closed contacts, and lets you series-connect several checks to speed up batch work. Overcurrent and overvoltage protection are built in.

A few practical notes from the field: always double-check your wiring and connector contact before energizing, make sure the output terminals form a closed loop (no loop, no current), and size your copper leads at roughly 10A/mm². The unit is rated for 5-minute short-duty cycles, so for heat-run testing plan around its long-duration rating.

For engineers in power, railway, petrochemical, metallurgy and mining who need a portable, accurate primary current injection tester, the 1000BS puts lab-grade output in a case you can actually carry. Reach out for the full spec sheet or a quote.