Frequently Asked Questions

In an Online Double Conversion UPS (VFI-SS-111 standard) (such as Vertiv Liebert, Eaton 9395XR, or Delta Modular), raw utility AC power is continuously converted to DC via an IGBT rectifier and then inverted back into perfectly stabilized AC sine-wave power. Because the inverter continuously powers the connected load:

• Transfer Time is precisely 0 milliseconds (0 ms) during blackout, voltage sag, or brownout events.
• Sensitive loads (microcontroller PLCs, CNC drives, automated medical analyzers, and enterprise servers) never experience power dropouts.

In contrast, offline and line-interactive UPS systems introduce a mechanical transfer delay of 4 to 12 milliseconds, which routinely causes tripping, controller reboots, and catastrophic production line downtime in industrial plants.

Inductive machinery draws massive starting inrush currents—frequently 4x to 6x full load current. While Variable Frequency Drives (VFDs) reduce starting inrush, they inject severe 5th, 7th, and 11th order current harmonics back into the electrical distribution.

When Northern EPES engineers size an industrial UPS:

• We apply a minimum 1.3x to 1.5x capacity headroom above total calculated running kW.
• We select inverters with high crest-factor handling (minimum 3:1 crest ratio).
• We integrate Active Harmonic Conditioners (Active Front End rectifiers) to keep Total Harmonic Distortion (THDi) strictly below 3%, fully compliant with IEEE 519 guidelines.

N+1 Redundancy: If a facility requires 'N' units of capacity (e.g. three 100kVA modules to power a 300kVA load), a fourth 100kVA module is run in parallel. If any one module experiences an internal component fault, it seamlessly isolates without any drop in output, and the remaining 3 carry the full load.

2N Redundancy (Dual Bus System): Provides two totally independent power paths from substation transformer to the dual-corded server rack or critical plant panel (System A + System B). Even if an entire substation bus, switchgear, or UPS system catches fire or undergoes planned maintenance, System B sustains 100% load. This is the hallmark of Uptime Institute Tier 3 and Tier 4 data center standards.

Each battery chemistry serves specific operational environments:

• SMF VRLA (Sealed Maintenance Free): Brands like Amaron Quanta and Exide Powersafe. Recombinant, zero water-topping required, clean for indoor server rooms. Typical design lifespan: 3 to 5 years.
• Tubular Flooded Lead Acid: Excellent deep-cycle durability (1,200+ cycles at 80% DOD). Ideal for severe rural power grids with frequent long outages. Requires dedicated ventilated battery rooms and quarterly electrolyte topping. Lifespan: 7 to 10 years.
• Lithium Iron Phosphate (LiFePO4): 3,000+ full charge cycles, 60% lower physical footprint, operates at higher ambient temperatures without degradation, and charges 4x faster (1-hour recharge). Higher initial CAPEX, but lowest 10-year Total Cost of Ownership (TCO).

Northern EPES mandates internal cell impedance and conductance testing at least quarterly for manufacturing lines and monthly for data centres.

When an internal battery plate sulfates, its internal resistance (milli-ohms) rises substantially long before its float voltage drops. Standard multimeter voltage checks will indicate a healthy battery when it is actually on the verge of open-circuit failure under discharge. Our engineers deploy calibrated Hioki 3554 battery testers to detect individual weak cells before they collapse the entire string.

Battery sizing is based on DC bus voltage, inverter efficiency, and high-rate discharge curves (Peukert's effect):

Required DC Current (Amps) = [UPS kVA × Power Factor] / [DC Bus Voltage (V) × Inverter Efficiency]

Because battery capacity non-linearly drops at high discharge rates (e.g., a 100Ah battery cannot deliver 100A for 1 hour; it delivers ~65A), we map required Watts-per-Cell (W/Cell) down to a safety End-of-Discharge cutoff (typically 1.67V to 1.75V per cell) using OEM manufacturer discharge tables.

We execute end-to-end turnkey High-Tension (HT) electrical infrastructure:

• Design & Sizing: Single Line Diagrams (SLD), short-circuit fault calculations, transformer kVA sizing, and cable trench engineering.
• Equipment Procurement: Oil-cooled and dry-type cast resin transformers, Vacuum Circuit Breakers (VCB), Ring Main Units (RMU), HT metering cubicles, and APFC capacitor banks.
• Civil & Structural Work: Transformer plinth construction, oil soak pit with gravel, lightning protection arrestors, and earth mat mesh installations.
• Testing & Commissioning: Relay secondary injection testing, transformer dielectric oil breakdown voltage (BDV) testing, and CT/PT polarity verification.

Yes. Northern EPES is a licensed 'A' grade electrical contractor. We handle complete statutory regulatory liaison:

• Submission of electrical drawings, earthing layout diagrams, and safety equipment layouts to the Chief Electrical Inspector to Government (CEIG).
• Pre-commissioning site inspections and physical verification by the regional Electrical Inspector.
• Procurement of official Charging Sanction Letters from State Power Utilities (MSEDCL, Tata Power, Torrent Power, Adani, BESCOM, etc.) prior to energizing the high-voltage breaker.

Under our Comprehensive Annual Maintenance Contract (CAMC), we guarantee:

• Tier 1 Metros (Mumbai, MMR, Pune, Delhi NCR, Bengaluru, Chennai, Ahmedabad): 2 to 4 hour on-site physical engineering response 24/7/365.
• Industrial Corridors & SEZs: Maximum 4 to 6 hour on-site arrival.
• Immediate Phone/Video Triage: Senior engineer online within 15 minutes to guide your facility team through safe bypass procedures while field crews mobilize.

Comprehensive AMC (CAMC): Full risk coverage. Includes all scheduled quarterly preventive maintenance visits, unlimited breakdown callouts, AND all replacement spare parts (IGBT power modules, driver boards, DC capacitors, cooling fans, control PCBs) at zero additional invoice cost.

Non-Comprehensive AMC: Covers scheduled preventive maintenance and breakdown service engineering visits. Replacement parts and consumables are quoted and charged separately upon client approval.

We are authorized distributors, channel partners, and certified service specialists for:

• UPS Systems: Vertiv Liebert, Eaton, Delta Electronics, Numeric Legrand, APC by Schneider, and BPE.
• Industrial Batteries: Amaron Quanta, Exide Powersafe, HBL Power Systems, Rocket, and Panasonic.
• Switchgear & Transformers: Schneider, ABB, Siemens, L&T, and Raychem.

All supplied equipment carries official manufacturer warranties, and our warehouse network maintains original OEM spare components for rapid repair.

Yes. We maintain a ready-to-mobilize fleet of Rental Online UPS systems from 10kVA up to 1000kVA+ with mobile battery trailers. Designed for:

• Emergency loaners during catastrophic substation or UPS transformer failures.
• Planned factory shutdowns, retrofits, and seasonal production spikes.
• Major corporate summits, data migration events, and exhibition backup power.

Systems can be dispatched with quick-connect power cables and on-site operating technicians within hours across major industrial corridors.

Legacy SCR/thyristor-based rectifiers suffered from poor input power factor (0.75 to 0.82 lag) and heavy harmonic injection (THDi > 30%), causing DISCOM electricity penalties (from utilities like MSEDCL, Tata Power, Torrent) and requiring oversized diesel generator sets.

Modern double conversion UPS systems supplied by Northern EPES incorporate IGBT Active Front End (AFE) rectifiers with active Power Factor Correction (PFC):

• Achieve near-unity Input Power Factor (PF ≥ 0.99) across 20% to 100% load.
• Eliminate low power factor billing surcharges from state electricity boards.
• Allow 1:1 generator-to-UPS sizing, saving substantial CAPEX on standby diesel generators.

The Static Bypass Switch consists of anti-parallel silicon controlled rectifiers (SCRs) that act as an ultra-high-speed electronic transfer mechanism. If the UPS inverter suffers an internal failure, severe overtemperature, or experiences an enormous branch-circuit short-circuit that exceeds inverter current limits, the static switch triggers in less than 2 milliseconds (< 2 ms).

This allows the raw utility grid to supply momentary fault-clearing energy without interrupting the downstream critical load bus. For scheduled overhaul, a mechanical Maintenance Bypass Breaker with Kirk-key mechanical interlocking isolates the UPS completely while keeping connected equipment powered.

In sealed lead-acid (VRLA) batteries, the oxygen recombination reaction is exothermic. Because lead-acid chemistry has a negative temperature coefficient of voltage, as internal cell temperature climbs, cell internal resistance drops, causing the charger to push higher float current. This generates more heat, culminating in bulging containers, electrolyte venting, and catastrophic battery fires.

Northern EPES implements rigorous prevention protocols:

• Installation of external temperature-compensated charging probes connected directly to the UPS charger logic, automatically dialing back float voltage by -3mV/°C per cell as ambient temperature rises.
• Strict adherence to 15mm minimum inter-cell spacing on seismic-certified steel racks to maintain convective air circulation.
• Precision battery room climate control maintaining 25°C ± 2°C ambient temperature.

Under the Battery Waste Management Rules (BWMR) enforced by the Central Pollution Control Board (CPCB) and State Pollution Control Boards (MPCB, GPCB, DPCC), spent lead-acid batteries cannot be discarded in general industrial waste or sold to unauthorized unorganized scrap aggregators.

Northern EPES provides 100% legally compliant closed-loop recycling:

• Issuance of official CPCB Form 8 & Form 13 disposal manifests and EPR credit transfer documentation.
• Safe palletized hazardous transit directly to ISO-certified primary lead smelting refineries.
• Commercial scrap buyback rebates credited directly against the invoice of replacement Amaron Quanta or Exide battery banks.

Selection between Cast Resin Dry-Type and Oil-Immersed transformers depends on facility geography, fire insurance underwriting, and building codes:

• Cast Resin Dry-Type (CRT): Class F or Class H insulation, non-flammable, and self-extinguishing. Mandatory by National Building Code (NBC) for basement substations, rooftop installations, hospitals, shopping malls, and enterprise data centres. Eliminates oil soak pits and fire suppression deluges.
• Oil-Cooled Transformers: Best suited for outdoor switchyards and high ratings (>2.5 MVA). Lower initial capital cost and superior heat dissipation in high-ambient industrial zones. Requires quarterly oil breakdown voltage (BDV > 60kV) testing and silica gel breather maintenance.

HT switchgear acts as the primary safety shield against catastrophic utility surges and internal short-circuit faults:

• Vacuum Circuit Breakers (VCB): Utilize hermetically sealed vacuum interrupter bottles where the dielectric strength of vacuum snuffs electrical arcs almost instantaneously during contacts parting. Rated for 25kA to 31.5kA breaking capacity for 3 seconds, paired with numerical microprocessor relays for overcurrent, short-circuit, and earth fault protection.
• Ring Main Units (RMU): Compact SF6 or solid-insulated switchgear units configured for ring distribution networks. Enable seamless isolation of faulty line sections while maintaining power flow to remaining industrial sub-plants.

Per Indian Standard IS 3043 (Code of Practice for Earthing) and CEA Regulations:

• Substation combined earth grid resistance must strictly measure below 1.0 Ohm (and below 0.5 Ohm for high-density IT/data center installations).
• Northern EPES installs maintenance-free copper-bonded steel electrodes surrounded by conductive carbon backfill compound, tested via 4-terminal Wenner Earth Megger method.
• Dedicated, isolated clean earth pits are provided for neutral grounding, body earthing, and lightning protection masts with test link disconnectors for annual inspectorate audits.

Our comprehensive preventive maintenance visits follow calibrated aerospace-grade checklists:

• FLIR Thermal Imaging (Thermography): Infrared scanning of all input/output busbars, breaker terminations, and SCR junctions to locate high-resistance loose connections before they melt or cause electrical fires.
• DC Bus Capacitor Health: Measuring AC ripple voltage on the DC bus to identify dried-out electrolytic capacitors nearing end-of-life.
• Calibration & Logic Check: Digital meter accuracy checks, static bypass transfer simulation, fan tachometer speed testing, and firmware event log downloads.

Because Northern EPES is an authorized channel partner for premier OEMs (Vertiv, Eaton, Delta, Numeric, Exide, Amaron Quanta), we do not rely on grey-market third-party components:

• We maintain regional bonded warehouses stocking 100% factory-sealed original OEM spare kits: Semikron / Infineon IGBT modules, gate driver boards, control PCBs, and DC cooling fans.
• Critical hot-spare spares are maintained within a 2-hour delivery radius of major industrial corridors in Mumbai MMR, Pune, Gujarat, and NCR.
• All replaced parts carry official OEM warranty documentation and test certificates.