The Cost of UPS Failure — Why Businesses Call Us at 2 AM
A three-phase industrial UPS protects assets that cannot tolerate even a 20ms power interruption: CNC machining centres mid-cycle, data centre server racks, hospital life-support monitoring systems, pharmaceutical cold-chain equipment, and industrial process control systems. When the UPS fails in bypass mode, those assets are exposed. When it fails with no output, they are dead.
The largest single cost of UPS failure is not the equipment damage — it is the production loss, the data corruption, the regulatory non-compliance event, or the patient safety incident. Every hour counts. That is why our clients call us from across Europe, sometimes in the middle of the night.
Three-Phase UPS Systems We Repair
APC by Schneider Electric — Symmetra Series
The APC Symmetra PX range (10–250 kVA, modular) and the legacy Symmetra LX and MW series are the dominant three-phase UPS in European data centres. We repair:
- Symmetra PX Power Module (SYPX16KH / SYPX20KH): Each 16/20 kW power module contains an independent rectifier-inverter stack. Failures: IGBT module burnout (symptoms: module goes to "failed" state with red LED, system derates by 16/20 kW), gate driver PCB failure, DC bus capacitor failure causing output voltage ripple exceeding UPS tolerance.
- Symmetra PX Static Bypass Board: The SCR-based static bypass fails when grid transients destroy the SCR trigger circuit. Repair requires SCR replacement and gate trigger IC replacement — we hold stock of common SCR types used across Symmetra range.
- Symmetra MX / LX Intelligence Module: The control card governing system management, RS485 communication, and SNMP reporting. Failures: flash memory corruption, Ethernet PHY IC failure.
- APC Galaxy 3500 / 5500 / 7000 / 9000 series: Larger fixed-frame UPS. We repair inverter driver boards, PFC rectifier boards, and the main DSP control board.
Eaton
- Eaton 9395 (60–750 kVA): High-power critical facility UPS. Key failure: the DSP control board (PCB 07-790023 and variants) failure causing "inverter fault" with no output. We repair the DSP board at component level — new boards from Eaton cost €2,800–6,000 and take 8–16 weeks. Our repair: €650–1,200 in 4–5 days.
- Eaton 9PX / 9SX (5–22 kVA): Three-phase output with single-phase input. Common failures: the inverter IGBT module, main control board, and battery management board.
- Eaton 93PM / 93E: Modular UPS. Power module failures similar to APC Symmetra PX — each module independently repairable without shutting down the frame.
- Eaton Powerware 9315 / 9355: Legacy systems still protecting critical loads. We repair inverter boards, rectifier SCR assemblies, and the EPROM-based control board.
Emerson / Vertiv — Liebert Series
- Liebert NX (10–120 kVA): Widespread in European manufacturing and healthcare. Common failures: IGBT inverter module, the input PFC board, and the DSP control PCB (part 415566G1 and variants). Symptoms of DSP failure: UPS transfers to bypass spontaneously, display shows "inverter fault."
- Liebert EXS / EXM (10–200 kVA): Modular systems. Power module PCB failures — we repair the inverter stage, the rectifier stage, and the DC/DC converter section independently.
- Liebert Hipulse U (10–800 kVA): Large industrial UPS. IGBT module replacement, thyristor rectifier assembly repair, and control electronics repair for this long-running platform.
- Liebert Series 600 / 610 / 700: Legacy systems. We reverse-engineer and repair DSP control boards for discontinued models where Vertiv no longer provides support.
Borri
- Borri 5000 EVO / B8000 / iQ series: Italian-manufactured UPS with strong European market penetration. Common failures: IGBT module (Borri uses Fuji or Infineon IGBT modules in a proprietary housing — we source exact replacements), the output filter capacitor bank, and the DSP control board. Note: Borri's support in Central/Eastern Europe is sparse — we are frequently the only repairer that can fix Borri systems without returning them to Italy.
Socomec
- Socomec Masterys IP+ / BC+ / GP+ (10–800 kVA): Used extensively in industrial and hospital environments. Common failures: IGBT module failure causing "inverter overcurrent" fault, the backplane communication bus between the DSP controller and power modules, and the LCD control panel PCB.
- Socomec ITYS-E / NETYS-RT: Three-phase output rack-mount. Common: main inverter board, input rectifier MOSFET, battery charging PCB.
The Most Common Three-Phase UPS Failure Modes
IGBT Module Failure in the Inverter Stage
This is the most common and most expensive UPS repair scenario. IGBT modules in a 50–200 kVA UPS cost €800–3,500 for the semiconductor alone. The module fails due to: battery discharge current surge during deep discharge, overload beyond rated kVA, or simply thermal fatigue after 7–12 years of continuous operation. Symptom: "inverter fault" or "inverter overcurrent" alarm, UPS transfers to bypass, output unprotected. We replace the IGBT module, test the gate driver circuit for secondary damage, and perform a full load bank test before return.
DC Bus Capacitor Bank Failure
The electrolytic capacitors on the DC bus store energy between the rectifier and inverter stages. After 7–10 years of continuous operation at 40°C ambient, their capacitance reduces by 30–50% and their ESR (equivalent series resistance) increases dramatically. Early symptoms: audible hum (120 Hz) from the UPS cabinet, occasional voltage dip alarms. Late symptom: "DC bus overvoltage" fault and inverter trip. We replace all DC bus capacitors as a matched bank — never single capacitors — and verify ESR on replacement parts before installation.
DSP Control Board Failure
The DSP (Digital Signal Processor) control board is the brain of the UPS. It generates the IGBT gate drive signals, regulates output voltage and frequency, manages battery state of charge, and handles communication with external management systems. DSP board failure causes total inverter shutdown. Because DSP boards are programmed with UPS-specific firmware that includes calibration data, replacement requires programming — we hold firmware images for all major platforms and can programme replacement boards at our facility.
On-Site Emergency Service
For UPS failures in data centres, hospitals, and other facilities where the unit cannot be easily removed, we offer on-site emergency repair across Poland and (with advance notice) the Czech Republic and Slovakia. Our technician travels with a diagnostic kit and the most common IGBT modules, DSP boards, and capacitor kits. We resolve approximately 60% of faults on-site on the first visit.
Cost and Turnaround
IGBT module replacement: €900–3,800 (module cost + labour). DSP control board repair: €550–1,400. DC bus capacitor replacement: €400–1,200. Standard send-in turnaround: 4–7 working days. On-site emergency: within 24–48 hours across Poland. We include a 12-month warranty on all repaired systems.