The small rear card that decides whether your rack starts

The 3500/15 power supply splits its work between two cards. The front power module does the conversion; the rear PIM — Power Input Module — connects the plant wiring and feeds it. Bently Nevada splits the AC PIM range into two part numbers by input voltage, and ordering the wrong one is one of the most common 3500 spares mistakes we see.

Which number matches your plant?

110 V plants, meet the 125840-02

North American plants, marine installations and many older refineries run control power at 110/120 V AC. A 3500 rack in those facilities needs the low-voltage AC Power Input Module — part number 125840-02 — rated for 85–132 Vac rms at 47–63 Hz. Feed it from a 240 V circuit and it will fail; fit the high-voltage 125840-01 on a 110 V supply and the rack simply will not start reliably.

Where the 110 V configuration shows up most

• US-spec turbine and compressor packages exported with the original control cabinet
• Marine propulsion and generator sets following 110 V standards
• Retrofit projects where only a 110 V UPS circuit is available near the machine

The revision trap

Voltage range also depends on hardware revision. PIMs earlier than revision R, paired with power modules earlier than revision M, accept only 175–250 Vac rms at the top end. If your 240 V supply sits at the high end of its tolerance band during summer peak load, an old-revision pair can trip on overvoltage. When replacing a PIM, check the revision letter on the label and match it with the front power module.

Practical advice

• Measure voltage at the cabinet terminals over a full day if possible, not once.
• Keep one spare PIM per voltage family present in your plant, not one spare total.

Need help confirming the right part number? Our engineers check rack compatibility and PWA revisions before every shipment — contact us for a quote or cross-reference. lizzie@swanautomation.com