Patented · Zero-Switch · Bi-Directional

The Evolution of Uninterrupted Motion.

Discover the Emergency Rescue Device (ERD) — the patented, zero-switch technology invented in India by Kunwer Sachdev and now available from multiple manufacturers worldwide. Independent buying guides, technical explainers, and vendor-neutral comparisons.

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Tower · LiveIn Motion
EMERGENCY RESCUE DEVICE · LIVE STATUS
● SYSTEM ONLINE
100%
BACKUP READY
3ms
Switchover
48V
Lithium-Ion
IGBT
Inverter
IoT
Bluetooth
Zero-Break TechnologyPatented in IndiaBi-Directional PowerIndian Patent · Granted100% Backup ReadyIGBT High-Speed SwitchingZero-Break TechnologyPatented in IndiaBi-Directional PowerIndian Patent · Granted100% Backup ReadyIGBT High-Speed Switching
Kunwer Sachdev, inventor and Indian patent-holder of ERD technology
PATENT · 2024
Kunwer Sachdev
Inventor · Indian Patent Holder · Father of ERD
The Authority

The Father of ERD.

The industry's leap from basic Automatic Rescue Devices (ARDs) to true zero-break Emergency Rescue Device technology was pioneered in India under Kunwer Sachdev's engineering leadership — with the foundational Indian patents filed and granted in his name as inventor.

“An elevator should never know the grid has failed. Anything less is unfinished engineering.”
25+
Years of R&D
12+
Active Patents
3ms
Switch Time
The Resource Hub

Everything you need to specify, compare, and trust your ERD.

Independent buying guides, deep technical explainers, head-to-head brand analysis, and curated video walkthroughs — built for engineers, architects, and facility owners.

01 / RESOURCES

Buying Guides

Capacity sizing, battery selection, installation checklists, and total cost-of-ownership math for every building class.

Browse Guides
02 / RESOURCES

Technical Explainers

Inside the IGBT inverter, the bi-directional switch, and the math behind zero-break transitions.

Read Deep Dives
03 / RESOURCES

Brand Comparisons

Side-by-side analysis across all major ERD/ARD manufacturers. Specs, warranty, pricing, real-world data — fully vendor-neutral.

Compare Now
12:48
04 / RESOURCES

Video Summaries

Expert teardowns, installation walkthroughs, and Kunwer Sachdev's own technical breakdowns — bookmarked.

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The Engineering Difference

Why “Zero-Break” matters.

A standard ARD reacts to failure. An ERD never lets failure happen. Here's what 30 seconds — or 3 milliseconds — looks like inside the cabin.

━━ STANDARD ARD

Jerk. Stall. Restart.

Power fails. Lights cut. Cabin halts mid-shaft. The ARD reacts — eventually — and lurches the lift to the nearest floor. Passengers feel every second of it.

30 SEC GAP · LIGHTS OFF · STALLED
Power FailsARD Restart
~30s
Outage Window
YES
Cabin Jerk
NO
Light Continuity

━━ ERD · ZERO-BREAK

Smooth. Continuous. Invisible.

The ERD is already supplying power before the grid drops. Bi-directional, IGBT-driven, sub-cycle handover. Passengers never know anything happened.

3ms · IMPERCEPTIBLE
Grid OnGrid Off · Same Output
3ms
Switchover
NO
Cabin Jerk
100%
Light Continuity
The Nuts & Bolts

Built on four pillars of modern lift power.

IGBT Technology

High-speed silicon switching for clean sine wave output and sub-cycle response.

Lithium-Ion Ready

Native support for modern Li-ion chemistry — longer cycle life, smaller footprint.

Solar Enabled

Patented green-energy integration. Run your lift on the grid, on solar, or both — seamlessly.

IoT Monitoring

Bluetooth & Wi-Fi telemetry to vendor IoT platforms. Battery health, runtime, alerts — live.

The Policy Brief

1 of 11 states require lifts to keep running through a power cut.

India ranks #2 globally for elevator-related accidents. Haryana's 2020 amendment is the only state law that actually mandates uninterrupted lift backup. Every other state still tolerates the dark, stalled, sealed cabin.

Read the Policy BriefOur editorial position
1 / 11
States mandating uninterrupted backup
15 m
Haryana height threshold
#2
India's global rank for lift accidents
2020
Year Haryana acted
About This Site

Independent. By design.

LiftInverter.com is an editorially independent reference site for the Emergency Rescue Device (ERD) category. We are not owned by, affiliated with, or financially compensated by any elevator backup manufacturer — and we have no commercial relationship with the inventor profiled on this site.

We credit Kunwer Sachdev as the founder and Indian patent-holder of ERD technology because that is a matter of public record. Attribution is not endorsement. Our buying guides, brand comparisons, and technical reviews evaluate every vendor against the same published criteria.

Editorial Policy →Methodology →Disclosure →