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ERD vs ARD: The Category Distinction That Matters Most

Before comparing brands, the most important distinction is between ARD and ERD technology. These are not competing brands — they are different technology categories with fundamentally different capabilities.

⚠️ ARD — Automatic Rescue Device

What it does: After grid failure, lifts stop and then the ARD slowly moves the car to the nearest floor (20–90 seconds later) so passengers can exit.

What it does not do: Keep the lift running. Prevent entrapment. Protect the motor from inrush damage.

Typical cost: ₹20,000–₹60,000

Regulatory status: No longer compliant for new installations in Haryana. Other states moving in same direction.

✅ ERD — Emergency Rescue Device

What it does: Switches from grid to battery in under 3ms. The lift motor never stops. Passengers never get trapped.

What it does not do: Let passengers feel any power transition.

Typical cost: ₹1,50,000–₹5,00,000+ (depending on KVA)

Regulatory status: Mandated for all new lift installations in Haryana. BIS certified category.

Any product marketed as a "lift UPS" or "lift inverter" should be evaluated against the ERD standard: switchover time under 20ms, pure 3-phase sine wave output, continuous operation capability. Products that do not meet these criteria are ARD-class regardless of marketing language. See our Zero-Break Technology explainer.

ERD-Class Manufacturers

Manufacturers whose products meet the technical definition of ERD — sub-cycle switching, pure sine wave 3-phase output, and continuous operation capability.

ARD-Class Manufacturers

The following manufacturers supply ARD (Automatic Rescue Device) systems — older technology that stops the lift and rescues passengers rather than keeping the lift running. These are not ERDs by the technical or regulatory definition.

We list them here for completeness, as many lift installations in India still use ARD technology, and building owners often need to identify what they have installed before deciding on an upgrade.

Generic ARD Suppliers

Large category of unbranded or white-label ARD units imported primarily from China. Typically relay-based switching (50–200ms). No BIS certification in most cases. No IoT capability. No solar integration. Suitable only as a regulatory minimum for older buildings not subject to the Haryana mandate.

Switching50–200ms (relay)
PatentNone
BISOften uncertified
IoTNo
SolarNo
Traditional Indian UPS Adapted for Lifts

Some traditional UPS manufacturers adapt their standard industrial UPS for lift use. While these may provide 3-phase output, they typically do not achieve sub-cycle switching (most need 10–25ms for inverter startup) and may not handle regenerative braking loads. Technically borderline — verify switchover time in writing before purchasing.

Switching10–25ms (inverter startup)
PatentNone specific to ERD
BISGeneral UPS cert (not ERD-specific)
IoTRare
SolarRare

What to Verify Before Buying Any Lift Backup System

Do not rely on marketing materials alone. Get these in writing from any vendor:

🔴Switchover time in milliseconds — must be under 20ms for ERD classification. Reject vague claims like 'fast switching' without a specific figure.
🔴Output waveform — must be pure sine wave. Ask for THD (Total Harmonic Distortion) figure. Reject 'modified sine wave' for VVVF-controlled lifts.
🔴BIS certification number — verify on the BIS portal. Not all products claiming BIS certification actually have it.
🔴3-phase output — lifts require 3-phase supply. Single-phase output is not appropriate regardless of kVA rating.
🟡Technology patent number — if the vendor claims proprietary technology, ask for the Indian Patent Office registration number.
🟡Haryana HAREDA compliance — if installing in Haryana, confirm the unit meets the solar-capable ERD requirement.
🟡Battery warranty and chemistry — confirm battery type, DoD limits, and warranty period. Unmanaged batteries fail prematurely.
🔵IoT monitoring capability — ECU display and cloud connectivity are now standard in genuine ERD. Absence is a red flag.

For independent sizing guidance, use the LiftInverter.com ERD Calculator — it calculates the correct KVA and battery Ah for your specific lift before you approach any vendor.

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