The challenge: Mission-critical upgrade for legacy pumping station
The High Lift Pump Station at Coppermills, commissioned in 1966, is a crucial part of Thames Water’s network. Over time, the original slip-ring motors became increasingly unreliable, leading to frequent failures and rising maintenance needs. With a new pumping station not expected for another decade, a phased replacement of all ten motors was identified as the most practical and strategic solution. The upgrade had to maintain operations and guarantee uninterrupted water supply for millions, even during critical maintenance on the delivery manifold.
Our solution: Smart engineering with minimal impact
Rather than proposing a disruptive overhaul with modern squirrel cage motors and variable speed drives, MENZEL supplied state-of-the-art TEAAC and TEWAC slip-ring motors engineered to match the existing infrastructure. By aligning with the original pedestals, starters, switchgear, and cabling, the new motors could be installed with minimal site modifications and downtime. This approach enabled fast commissioning while delivering modern performance, improved reliability, and long-term service life – all without the disruption or high costs of a full system redesign.
Technical data of the 10 IEC/EN 10-pol slip-ring-motors
The scope of delivery included four totally-enclosed air-air-cooled motors (TEAAC also known as CACA) and six totally enclosed water to air cooled type (TEWAC) motors
- Menzel motor type: MEBSSW500-10 and MEBSSL500-10
- Rated Power: 746 kW and 343 kW (1,000HP and 460 HP)
- Rated Voltage: 3,300 V
- Rated Speed: 590 min⁻¹
- Frame Type: IM 3011 (IM V1)
- Protection Class: IP 55
- Cooling method: IC 81W and IC 611
- Weight: 7,400 kg each
Project goals achieved: Lower cost, higher efficiency
The replacement strategy achieved all project goals. The new motors significantly increased energy efficiency and reliability, all while staying well within budget. Unlike alternative proposals involving VSDs and new cage motors, the Menzel solution avoided high investment costs and future-proofed the station with low-maintenance, high-performance machines.
By matching the original design footprint and terminal box positions, Menzel ensured minimal downtime and no expensive cable works saving not only time and money, but also reducing environmental and logistical impact.
Engineered for today and tomorrow
Working closely with MWH Treatment, the EPC contractor, and Thames Water’s site team, Menzel tailored every aspect of the motors to the specific requirements of the project. This included thermal considerations in anticipation of future climate extremes and long-term serviceability.
The motors were designed for a service life of up to 25 years, using more sustainable materials and modern winding insulation systems. With this solution, Thames Water was able to maintain full HLPS functionality, even during essential repair work on the
Menzel’s engineering team impressed us with their deep understanding of both technical and site-specific constraints. Their solution allowed us to retain our infrastructure, cut emissions, and stay on budget without compromising reliability.
Award nominated solution
However, our project solution not only impressed our customer in the UK. The AEMT also recognized the idea and its implementation with a nomination for the AEMT Award 2025, one of the most prestigious business awards in the UK.
The AEMT Awards are an annual award presented by the Association of Electrical and Mechanical Trades (AEMT) to honor outstanding achievements in the electrical and mechanical engineering industry. The awards recognize innovation, excellence, and expertise in areas such as product development, technical skills, training, and sustainability.
