Case Study

Metal Machining Company (year 2011, province of Torino)

ISSUE THAT WAS FOUND: high electricity cosuptions coming from the number of elctric motor in use. Cost of energy = 0.130 €/kWh

Intervention plan:

• inventory of every motor in the factory, with the collection of relevant technical data (power, year of installation, efficiency, uptime hours per year, load factor, …). This is done with the goal to calculate the total electric energy consumed in one year, the bearing over the total consumption of the factory, which are the motors with the biggest consumption that deserve primary attention
• double check that the proposed use of high-efficiency motors is economic advantageous, both in the cases of breakdown of an existing motor or of replacement of a working one)

ADOPTED SOLUTION: replacement of the existing motors with high-efficiency ones class IE3

COMPARISON AFTER/BEFORE INTERVENTION:

Initial configuration: 10 running electric motors, each with nominal power of 55 kW

Characteristic of each motor:

• power: 55 kW
• load: ¾
• uptime: continuous, 24/7
• efficiency: 91.5%

Final configuration after intervention: 10 high efficiency motors, each with nominal power of 55 kW

Characteristic of each motor:

• power: 55 kW
• load: ¾
• uptime: continuous, 24/7
• efficiency: 95.1%

The advantages of high-efficiency motors are:

• smaller losses (from friction, ventilation, in the void steel, because of Joule effect) respect to a traditional motor
• lower heat production, therefore a smaller fan is needed. This, in turn, translates into smaller mechanical losses

CONCLUSION: annual energy saving of 149490 kWh, corresponding to 19500€