Motor saves company GBP 16,000 a year

Edited by the Engineeringtalk editorial team Jul 9, 2007

An inverter drive package from Deritend has offered B Mason and Sons savings of around 20% on a 250kW motor.

Birmingham-based B Mason and Sons is saving over GBP 16,000 per annum in energy costs on just one 250kW motor, since installing an inverter drive package from Deritend.

The package, including the cost of the new Siemens MicroMaster inverter, refurbishment of the 250kW motor, and supply and installation of LV equipment, cost GBP 17,000, providing a 12.5 month payback for B Mason, with subsequent energy savings going to offset any future rise in the company's energy costs.

B Mason is the UK's largest manufacturer of precision rolled copper and copper alloy strip, and a major supplier to demanding markets worldwide.

In addition to continuous improvement of its plant and processes, the company has a commitment to responsible environmental practice.

Recently this commitment led to an energy audit in its strip plant.

The audit, undertaken by Deritend, quickly identified one major area, fume extraction, where substantial energy savings could be made.

B Mason has a number of furnaces, all of which use the same extraction and filtration plant.

The plant is run from a 250kW motor, which, until recently, was operated at full speed 7-days a week.

However, this continuous operation turned out to be unnecessary as all furnaces are not always required to be in operation at the same time.

Deritend applied an energy meter to the 250kW motor and calculated that by reducing the supply frequency by 10%, or 5Hz, substantial savings on the motor operation of around 20% could be achieved.

However, reducing the speed of the motor with its existing starting arrangement was not possible, so a decision was taken by Ray Ullah, B Mason's Maintenance Engineering Manager, to put in for capital to uprate the system to inverter control, using as justification the calculated savings and projected payback data supplied by Deritend.

Following project cost approval, the 250kW motor was removed and refurbished; the motor was rewound specifically to optimise it and protect it for inverter operation.

This included the fitting of an insulated bearing.

In addition, the motor windings were cleaned, re-insulated and fully tested.

At the same time Deritend personnel - working offsite so as not to interfere with production - installed the Siemens inverter and new contactors into an additional control panel and provided new cabling.

The total job, including motor refurbishment, and panel assembly, was completed by Deritend during B Mason's nine-day shutdown to minimise disruption.

The panel was installed by B Mason, and Deritend then commissioned the drive.

Subsequent to the installation, an energy meter was fitted to the 250kW motor and monthly readings taken.

These revealed that the substantial savings calculated by Deritend were actually being realised.

Previous to the installation of the inverter system, the yearly running cost of the 250kW motor was GBP 79,680.

With the inverter system in place, and the supply frequency reduced by 10%, this yearly figure has been reduced to 63,360 GBP a saving of 20.48% in energy costs.

The savings thereafter will be a boost to the company 's bottom line.

"It has performed exactly as promised, and we are really pleased", said Ray Ullah.

"Deritend told us that we could expect energy savings of around 20%, and that's just what we got".

"They also handled the project really well in the pressurised nine-day period of our shutdown".

"Then they suggested other ways that we could save energy by using different drive belts and the like".

"All in all a very successful project, and one that not only benefits us as a company, but also the environment, as it helps us to reduce our carbon footprint".