Introducing the Lift Inverter ERD Backup Calculator — Designed by Our Mentor, Kunwer Sachdev
Introducing the free Lift Inverter ERD Backup Calculator
A power cut should never trap anyone between floors. We are proud to introduce a free tool that tells you exactly how much battery backup your elevator’s Emergency Rescue Device (ERD) really needs — designed by our mentor, Kunwer Sachdev, the inventor of the ERD itself.
Why we built it
Sizing an elevator ERD is deceptively tricky. A lift is not a steady load — it pulls a heavy surge when the motor starts, then far less while levelling and idling. Guess too low and the ERD cannot finish a safe rescue run during a long outage; guess too high and you pay for capacity you will never use. After years of seeing buildings get this wrong, our mentor Kunwer Sachdev — the engineer who invented and patented the Emergency Rescue Device in India — designed a calculator that gets the number right in seconds.
Meet LiftInverter.com — and why it exists
The calculator lives on LiftInverter.com, an independent, vendor-neutral resource dedicated entirely to elevator backup and Emergency Rescue Device (ERD) technology. It was built to fix a simple problem: trustworthy, unbiased information about lift backup is scattered and hard to find. LiftInverter.com brings it together in one place — plain-English buying guides, technical explainers on zero-break and IGBT technology, brand-by-brand comparisons, full specifications, and the policy picture on lift safety in India.
The purpose is straightforward: help engineers, architects and building owners specify the right ERD with confidence — and make sure a power cut never leaves anyone trapped in a lift again.
What the calculator does
Reads your real load
Enter the lift’s motor rating (kW / HP) and floors, and it models the actual rescue-run energy — not just a flat wattage.
Sizes the battery
It returns the exact battery voltage and capacity (Ah) you need for the backup you want — lithium or lead-acid.
Guarantees rescue runs
Tell it how many rescue cycles and how much standby you must cover on battery alone, and it solves for it.
Vendor-neutral
Built on a published, transparent method — so you can specify and compare any ERD with confidence.
Try the Lift Inverter ERD Backup Calculator
Enter your lift’s motor rating, floors and the backup you want — get the exact battery and capacity in seconds. Free, and designed by the inventor of the ERD.
Open the Lift Inverter Calculator →How to use it in four steps
- 1Find the motor rating in kW or HP from the lift name-plate or controller.
- 2Set your guarantee — how many rescue runs and how much standby time you need during an outage.
- 3Choose battery voltage and chemistry (a 48V lithium bank is common for ERDs).
- 4Read the result on the Lift Inverter calculator — and specify with confidence.
Part of the Series
Home UPS & Inverter Buying Guide India 2026Explore Products
Su-vastika Home UPS / Inverter
25+ patents · Made in India · 10,000+ installations