List of Energy Saving Ideas in Motors | Motor management plan

Motors consume more than 75% of industrial load across the globe. Knowingly or unknowingly huge amounts of energy is getting wasted due to the non-optimum operation of these motors. Lack of awareness is also one of the important factor contributing to this non-efficient usage of motors. 

When a company is planning for procuring a motor for some application, the technical manager calculates the required power and torque for the said application and decides one rating to procure say 100kW. Then it goes to the section head where he adds some margin to be on the safer side and decides the rating as 120kW. At last, the role of management and the purchasing department comes into the picture: they add a few more margins considering the future expansions were and make the final rating of a motor to be procured as 140kW. Generally, no motor runs at its full load for more than 50% of the times and keeping the overload conditions, the technical manager would already oversize and post, so that others get added up making the capacity of a motor almost double. Now let's see what are the ill effects of oversizing a motor below:

Negative effects of Oversized Motor:

• Runs at low Power Factor
• Efficiency drops drastically at less than 50% load
• Results in more power consumption for the same load 

So just an oversizing is creating a huge energy wastage there are several other factors which need to be optimised. Few energy-saving ideas have been listed as below:

• Use of energy-efficient motors greater than IE3 for new and replacements
• Properly size the motor for optimum efficiency
• Provide proper ventilation. For every 10 °C rise in temperature above recommended peak, the motor life is estimated to be halved.
• Avoid over-voltages: more than 415 V. For every 10% decrease in voltage on an underloaded motor can save around 4% of energy. The performance of motors varies with applied voltage.
• Provide a balanced supply voltage. Imbalance can cause around 3 - 5% of energy losses.
• Practically limit motor re wounding less than 3 times. More number of rewindings and poor job may result in around 8 - 10% losses
• Change motor end terminals from delta to permanent star if loading is observed less than 33% permanently.
• Incase if loading is less than 33% for most of the times then use an auto star-delta mechanism that works based on current sensing.
• Use flat belts on the drives that are 3 -5% more efficient than V belts 
• Use variable speed drives on major motors having constant torque 
• Use motor surface-mounted sensors for continuous monitoring of vibration, temperature and other maintenance-related parameters of a motor.