re:3D GigabotX 2 XLT 900 Power Assessment at JIFX 26-3
Continuous Waveform Measurement during Printing Operations
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Every aspect of the printer's electrical operation, observed over a 24.8-hour window spanning 12 printed parts, was found to be consistent with standard, best-practice engineering — controlled, zero-cross-aligned switching of the main heater; tight regulator-driven duty cycling; smooth motion-side current through the internal DC bus; clean supply within ANSI C84.1 Range A for >99% of the window; and per-part energy in the expected band for the machine class.
No observable operational concerns: peak current ≈ 10.8 A on a 20 A circuit, with substantial headroom.
The McMillan hangar grid feed itself measured cleanly: median 121 V, frequency stable at 60.005 ± 0.05 Hz, voltage THD <2% (well under the IEEE 519 5% limit), and a ~0.37 Ω source impedance at the printer's outlet — a stiff, quiet supply for a field facility.
The work validates comprehensive equipment assessment from a single point of measurement — load disaggregation and supply characterization across time scales from 32 ksps waveforms through daily energy budgets — using continuous point-on-wave (CPOW) metrology, bench-calibrated against a 6½-digit reference DMM to ~1% accuracy on current and <0.5% on voltage at the loads observed.
Headline findings
- Five distinguishable operating modes inferred from the AC power signature — a cross-product of heater state (off-duty vs full-on burst) and motion state (steppers / extruder de-energized vs energized), plus an idle baseline. Levels: ~52 W / ~210 W / ~300 W / ~1.04 kW / ~1.19 kW.
- Energy consumed: 4.08 kWh across 12 parts over the 24.8 h window — 1 long part in Session 1 (1.09 kWh / 139 min), 11 shorter parts in Session 2 (mean 0.27 kWh, range 0.087–0.74 kWh; 2.99 kWh total).
- Peak draw ≈ 1.30 kW at the heated bed during a printing burst; running RMS stays well under 11 A over longer windows.
- Supply within ANSI C84.1 Range A for >99% of the window; deepest heater-burst transient briefly dipped to 113.0 V (0.942 pu), well above the 0.9 pu / 108 V IEEE 1159 sag threshold. Frequency exceptionally stable at 60.005 ± 0.05 Hz.
- Source impedance ≈ 0.37 Ω at the printer's outlet (V-vs-I slope at the plug), giving a steady voltage droop of ~0.37 V per amp of additional draw.
- The printer's AC-DC supply isolates motor switching from the AC inlet: the NEMA 23 steppers are PWM-chopped on the printer's internal 24 VDC bus, and that switching is filtered out before reaching the inlet. Motion activity therefore shows only as a smoothly-varying base-load lift in heater-on-duty mode, with no stepper-PWM spectral content upstream.
Provenance
- Sensor: EQ Wave™ Waveform Measurement Unit (WMU) v1.1 hardware, 32 ksps CPOW + 5 Hz power-monitor (PMon) aggregates, bench-calibrated against a Siglent SDM3065X-SC reference (both current and voltage channels).
- Asset: re:3D GigabotX 2 XLT 900 large-format fused-granulate-fabrication (FGF) printer (U.S. Army property, manufactured and operated at the event by re:3D).
- Site: hangar at McMillan Airfield, Camp Roberts (NPS Field Laboratory), near Paso Robles, CA; grid-connected 120 VAC.
- Window: 2026-05-12 16:39 PDT → 2026-05-13 17:25 PDT (~24.8 h), spanning two distinct printing sessions.
- Engineering review: re:3D's engineering team has reviewed the findings; two initial inferences were corrected and reflected throughout this draft (hopper / barrel heater is DC-driven, not AC; current channel was found to be mis-scaled due to an internal differential burden pairing — now bench-calibrated).