Saving Advice Electric Motors

Saving Advice Electric Motors

Electric motors are major users of electricity in industrial plant and commercial premises. Motive power accounts for almost half the total electrical energy used in the UK and for nearly two-thirds of industrial electricity use.

Key Measures

• The low cost of buying a motor can be deceptive. The electricity bill for a motor for just one-month can be more than its purchase price. Consequently, it is important to consider carefully the options when replacing motors or installing new equipment.




• Higher efficiency motors are now available at little or no cost premium compared with standard motors.
• Just concentrating on the drive itself can mean that significant and often low cost energy saving opportunities in the system that the drive is powering can be missed. Critically examine the efficiency of the system being driven and reduce the load on the motor where possible.
• In pump and fan applications, even a small reduction in speed using a Variable Speed Drive (VSD) can produce substantial savings. Also, speed control is a much more energy efficient method of regulating flow than throttles, dampers or re-circulation systems.

Practical Tips

Consider whether the drive system is still doing a useful job. Changing requirements may have eliminated the need for equipment that is still left running.

The simplest way of reducing energy consumption is to switch off the motor when it is not needed. Possible techniques include manual switching off, interlocking, time switches and load sensing.

Minimise motor losses by always specifying higher efficiency motors (HEMs) where feasible.

When motors are sent for repair, ensure that proper care and attention is given to the repair process. Otherwise significant reduction in efficiency can result.

Ensure all equipment is maintained properly.

A low cost method of saving energy by reducing speed is to change pulley sizes on belt-driven systems.