7.5 HP Motor Running Cost Calculator

Estimate the electricity cost of a 7.5 HP (5.5 kW) industrial motor — common size for medium pumps, compressors and conveyors in Indian factories.

⚡ 7.5 HP / 5.5 kW

Enter Your Operating Conditions

Motor power is fixed at 7.5 HP (5.5 kW). Adjust load factor, efficiency, hours and tariff to match your situation.

Typical: 75–85% for 7.5 HP industrial use
7.5 HP IE2: 87.7% min | IE3: 89.5% min
Industrial tariff in India: typically ₹6–12 per kWh

📊 7.5 HP Motor Cost Breakdown

Actual Power Draw
—
Cost per Hour
—
Cost per Day
—
Cost per Month
—
⚡ Annual Electricity Cost (7.5 HP)
—
Monthly Energy Consumption
—
Formula: Actual kW = 5.5 × Load% ÷ Efficiency%  |  Cost = Actual kW × Hours × Tariff
💡 IE3 Upgrade for 7.5 HP: Replacing IE1 with IE3 saves about —/month (6–7%). For a 7.5 HP motor running 8 h/day, payback is typically 14–20 months — a no-brainer for new installs.

About 7.5 HP Motors

7.5 HP (5.5 kW) is the standard step up from 5 HP and very common in mid-size Indian industry — driving medium centrifugal pumps, screw compressors, blowers, conveyors and small mixers.

Electrical input: A 7.5 HP motor at full load (90% efficiency) draws about 6.1 kW from the supply. At 80% load — typical for steady-state industrial use — input drops to ~4.9 kW.

Starting current: 6–7× full-load current with DOL start (about 80–100 A peak at 415V). Indian electrical norms expect star-delta starter on 7.5 HP and above to limit inrush. Soft starters add ~₹15,000 cost but eliminate belt slip and starter wear.

BEE star rating note: From 2024, IE3 is the legally-mandated minimum for new 7.5 kW class motors sold in India. IE4 (super-premium) is increasingly available with 1–2% additional efficiency gain.

⚡ Compare Other Motor Sizes

🏭 Any HP Motor (Custom) 5 HP Motor Cost 10 HP Motor Cost 15 HP Motor Cost 20 HP Motor Cost

📘 Related Resources

Disclaimer

Educational estimate using typical 7.5 HP motor characteristics. Actual numbers depend on motor model, ambient temperature, supply voltage and exact load profile.

Worked Examples — 7.5 HP Motor

These examples assume 80% load factor and 90% efficiency (actual electrical draw ≈ 4.9 kW). Adjust the calculator above for your exact conditions.

Example 1 — Single shift (8 hrs/day, 26 days/month)

Tariff: ₹8/kWh

Daily energy = 4.9 × 8 = 39.1 kWh/day
Monthly energy = 39.1 × 26 = 1,019 kWh/month
Monthly cost = 1,019 × ₹8 = ₹8,150/month
Annual cost ≈ ₹97,800/year

Example 2 — Double shift (16 hrs/day)

Conditions: 16 hrs/day, 26 days/month, ₹8/kWh

Daily energy = 4.9 × 16 = 78.2 kWh/day
Monthly cost = 78.2 × 26 × ₹8 = ₹16,300/month
Annual cost ≈ ₹1,95,500/year

Example 3 — Continuous (24×7 process plant)

Conditions: 24 hrs/day, 30 days/month, ₹8/kWh

Monthly energy = 4.9 × 24 × 30 = 3,528 kWh/month
Monthly cost ≈ ₹28,200/month
Annual cost ≈ ₹3,38,800/year

Continuous operation costs roughly 3.5× a single-shift operation. For batch processes that idle motors, a VFD with auto-stop typically saves 15–25% annually.

Frequently Asked Questions — 7.5 HP Motor

A 7.5 HP motor (5.5 kW rated) at 80% load and 90% efficiency draws about 4.9 kW of electrical power. That's roughly 4.9 kWh per hour. At full load, input rises to about 6.1 kW (electrical input = mechanical output ÷ efficiency).

At 8 hrs/day, ₹8/kWh, 80% load, 90% efficiency: a 7.5 HP motor consumes about 39 kWh/day costing roughly ₹313/day. Double-shift (16 hrs) doubles this. Costs scale linearly with hours and tariff.

At 8 hrs/day and 26 working days, a 7.5 HP motor consumes approximately 1,019 units per month. Monthly cost at ₹8/kWh ≈ ₹8,150. Continuous operation roughly triples this.

Yes. 7.5 HP × 0.746 = 5.595 kW, conventionally labelled 5.5 kW on Indian motor nameplates. This is the mechanical output rating. Electrical input depends on efficiency — at 90% efficiency, full-load draw is ~6.1 kW.

Star-delta is standard for 7.5 HP three-phase motors — it limits starting current to about one-third of DOL (~30 A vs ~90 A peak). For frequent starts, varying loads, or process control needs, a VFD or soft starter is better despite the extra cost. Bare DOL starting is technically allowed but stresses the supply transformer and the motor windings.

If your continuous load is under ~5 kW, 7.5 HP is more efficient — it operates at 80–90% load (efficiency peak zone). A 10 HP motor on the same load runs at only 50–60% load where efficiency drops by 3–5%. Oversize only if load is expected to grow, starts are very frequent, or peak-load demands brief overload capacity.

📦 Embed this calculator on your site

Free for any blog, forum or LinkedIn post. Copy this snippet — attribution to Anedya Enterprise is included automatically.

↗ Preview
Paste anywhere — the iframe auto-detects context and renders in compact embed mode.