Online UPS.

Choose double-conversion online UPS for medical, broadcast and mission-critical loads. Line-interactive UPS uses a transfer switch that introduces a 4–10 ms gap when the grid drops. For most office equipment that gap is invisible; for medical devices, broadcast servers, fire-alarm panels, switching-mode power supplies running tight tolerances and any equipment with sensitive transformers, that gap registers and over time accumulates as failures. Double-conversion online removes the question: there is no transfer event because there was never a switching path. We use line-interactive only where the load can genuinely tolerate it.

UPS battery autonomy is typically 10–15 minutes for buildings with diesel backup, 30–60 minutes for IT loads without generators, and longer with redundancy for critical-care clinical loads. We size it to the longer of two windows: the time your generator takes to start and stabilise, plus a 50% safety margin; or the time the load needs to shut down cleanly.

Choose lithium-ion for new UPS deployments above 20 kVA — 3–4× cycle life, half the floor space and 30–45% lower 8-year lifetime cost than VRLA. 3–4× cycle life, half the floor space and a fraction of the maintenance versus VRLA. Initial cost is ~2× but lifetime cost is typically 30–45% lower over 8 years. For new installations above 20 kVA we almost always recommend lithium. For sub-20 kVA loads with short autonomy requirements, VRLA remains acceptable.

Online UPS AMC scope includes quarterly preventive checks — capacitor inspection, fan-bearing health, internal-temperature trend, log review and a battery-bank impedance test (or BMS report for lithium) — plus an annual full discharge test, firmware patching on schedule and a spare-board pool for the modules in your rack. Response targets are documented in writing for the Guwahati metropolitan area and structured around scheduled rotations elsewhere.

Yes — we coordinate the UPS with the building's diesel generator and automatic transfer switch as one engagement: runtime calculations, ATS logic, harmonic-load coordination and the documented start-up sequence. The whole power chain is treated as one system rather than three contracts.

Yes in most cases — a careful audit of UPS firmware, charging-curve compatibility, communications interface and physical mounting tells us whether the existing UPS supports lithium without replacement. Many recent generations of Vertiv, Delta and Fuji modules do. We provide the audit report before quoting; if the UPS itself needs replacement we will say so.

It is one layer, not the whole answer. Double-conversion isolates the load from sag, surge, harmonics and frequency drift on the mains, but a direct or nearby lightning strike calls for a coordinated protection design — surge protection at the distribution boards and a sound earthing system — engineered alongside the UPS. In a high-lightning region like the Northeast we treat the two as one conversation.

Almost always heat. VRLA battery life is rated at a controlled ambient temperature, and a widely used engineering rule of thumb is that service life roughly halves for every ten degrees above it — so a battery bank in a hot, unventilated room quietly loses years. Ventilation, charging settings and periodic impedance testing are what close the gap between datasheet life and real life.

Usually the critical loads. The honest design separates essential circuits at the distribution board — servers, clinical equipment, fire and security panels, the network stack — and sizes the UPS to those, letting the diesel set carry the general building load after its start-up window. Backing everything through the UPS inflates the battery bank for loads that can tolerate a brief gap.