Evaluating the Cost-Benefit of Motor Rewinding vs. Replacement in Mining OperationsÂ
When two critical motors—rated at 18.5 kW (25 hp) and 90 kW (120 hp)—burned out, the maintenance team faced a common decision: rewind or replace. While rewinding is often less expensive upfront, it can result in reduced efficiency. This case study presents a comparative cost analysis, revealing that motor replacement offers greater long-term value, with a break-even point reached within two years.
Category: Blogs, Case Studies January 4, 2026
Intended Audience: Mining Engineers, Maintenance Managers, Electrical Supervisors
Objective: To determine whether rewinding or replacing failed motors is more cost-effective over the operational lifecycle, considering energy efficiency and total cost of ownership.
Description of System: The 18.5 kW and 90 kW motors in question were integral to a mining facility’s operations. Both had failed and were candidates for either rewinding or replacement with modern, high-efficiency models.
Description of Intervention: Industry surveys indicate that rewound motors typically operate at 1–2% lower efficiency than their original specifications. Using manufacturer-provided efficiency data for new motors and estimated post-rewind performance, a detailed cost analysis was conducted. The results, summarized in Table 1, form the basis for the decision-making process.
See Table 1 below:
Table 1: Motor Cost Values
| Motor | Motor | |
| Parameter | 18.5 kW (25HP) Motor | 90kW (120HP) Motor |
| Efficiency of Original Motor | 90 | 92.5 |
| Rewound Motor Efficiency | 89 | 91 |
| New Motor Efficiency | 92.5 | 95.2 |
| Rewind Cost (EUR/USD) | 850 | 4500 |
| New Motor Cost (EUR/USD) | 1400 | 7500 |
Summary of Results: A secondary evaluation was conducted to assess the justification for replacing older, yet operationally sound, motors solely for the purpose of improving energy efficiency. For this analysis, the motors’ operating efficiency was assumed to align with their original catalog specifications. The motors are in operation for 16 hours per day at 90% of their rated full load capacity.
Table 2: Motor Cost Values
| Parameter | Rewound 18.5kW (25HP) | New Efficient 18.5kW (25HP) | Existing Old 18.5kW (25HP) | Upgrade Sound to an Efficient 18.5kW (25HP) | Rewound 90kW (120HP) | New Efficient 90kW (120HP) | Existing Old 90kW (120HP) | Upgrade Sound to an Efficient 190kW (120HP) |
| Energy Consumed P.A. MWh | 109 | 105 | 108 | 105 | 520 | 497 | 511 | 511 |
| Energy Cost P.A. Euro/USD | 8180 | 7880 | 8100 | 7880 | 39 000 | 37 300 | 38 300 | 37 300 |
| Lifetime Energy Cost Euro/USD | 123 000 | 118 000 | 121 500 | 118 000 | 585 000 | 559 500 | 574 500 | 559 500 |
| Investment Cost Euro/USD | Basic | Additional 550 | 0 | 1400 | Basic | Additional 3000 | 0 | 7500 |
| Full Relative Life Cycle Cost Euro/USD | 123 000 | 118 500 | 121 500 | 119 400 | 585 000 | 562 500 | 574 500 | 567 000 |
| P.V. Relative Life Cycle Cost Euro/USD | 84 000 | 82 300 | 84 900 | 83 200 | 404 800 | 390 000 | 397 500 | 394 000 |
| Payback Years | – | 1.8 | – | 6.3 | – | 1.8 | – | 7.5 |
Conclusion: Replacing a failed motor with a new, energy-efficient model results in a payback period of less than two years, making it a financially prudent choice.
Replacing a functioning motor solely for improved efficiency is generally not cost-effective unless the organization is willing to accept longer payback periods, typically greater than six years.
Written by:
Members of the Pump Life Cycle Cost Guidebook Committee, 1st EditionÂ
Published In: Pump Life Cycle Cost: A Guide to LCC Analysis for Pumping Systems, 2nd EditionÂ
Year of Publication: 2021Â
Pump Life Cycle Costs: A Guide to LCC Analysis for Pumping Systems – 2nd Edition – Pumps.org
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