The Problem
Mayflower Vehicle Systems in Coventry manufactures body panels for, among other, Aston Martin and MG-F cars.
With the introduction of the Climate Change Levy (CCL) the cost of electrical energy has increased. Mayflower has also implemented the environmental management standard, ISO 140001 and as such is driven towards meeting environmental targets, which includes a significant reduction in CO2 emissions.
A major concern for their process was the 30kW phosphate / Alkali rinse pumps used in Mayflower’s nine stage pre-treatment system for the panels, that were running for 10 hours per day. With the existing star-delta starter arrangement, the motors could not be turned on and off quickly to meet the rinse pump’s duty cycle, without severely damaging the motor’s windings and bearings.
Sentridge’s Solution
A Sentridge energy audit of the paint plant revealed that the pumps needed the motors for just over two minutes of its eight-minute duty cycle.
Applying ABB drive technology on all pumps allowed the process to continue without the need to continuously repair burnt out motors.
With ABB’s ACS 600 and Comp-AC variable speed drives installed, Mayflower has been able to change its control strategy and cut the running costs of the pumps by 87.9%.
The Full Story
The cost savings were immediate. In fact, such were the project savings, the management of Mayflower committed £30,000 which had not been budgeted. The money was used for the purchase and installation of six drives for the phosphate and alkali rinse, chemical and soap pumps and a further 1 drives for other pumps and cooling tower applications ranging from 2.2 kW to 55kW. The investment is expected to yield a return in less than 12 months.
Other savings have resulted from reduced maintenance. For example, the 11kW soap pump was throttled manually to achieve 3 bar, but the valve would regularly work loose. Using PID control on an AC drive, to control the pump, not only avoids the manually valve adjustment, but provides a faster, more reliable control method
Sentridge Control’s energy audit is a systematic examination of key pump and fan applications that include the monitoring of energy consumed both before and after the change to AC drives. So confident were Sentridge about the results the audit would achieve that the company loaned an ABB drive to Mayflower to test its findings.
Pat O’Sullivan, Facilities Manager for Mayflower Vehicle Systems at the time, explained, “The paint plant runs 58 hours per week, 46weeks per year. Sentridge monitored the current in the phosphate pump motor during two weeks of production. After seeing the energy being saved before my eyes, I was converted.”
NB: While this case study dates back to the early 2000s, the energy-saving proficiency of ABB drives remains highly relevant. Given the current electricity costs, the impact of ABB drive solutions has expanded even further.