Worcester Business School

Email: Energy efficient motors

Email 

To: Lalit Choudhary  
General Manager  

From: Paul Collingwood  
Production Manager  

Date: 15th December 2022 

Subject: Re New Motors for machines  
_______________________________________________________________________  
Lalit,  
I have looked into more energy efficient motors for our 5 PVC vacuum forming machines, 3 PBT moulding machines and 2 extruders (various plastics) as you have asked. I have used conservative operation times for the purpose of this exercise, with only 16 hours (high peak) and 8 hours (low peak). We typically operate longer hours than this, so the savings would be greater (and the payback period shorter) in reality than my findings below:  
Currently motors on the machines are traditional electric motors rated at 3-phase 18kW load. They are variable speed with a mechanical adjustment.  
It is proposed that the motors be replaced with a modern equivalent utilising electronic variable speed drives (VSDs). These would give an average efficiency improvement of 3%. The 10 machines run constantly during the working day. Assume 75% loading in use, utilisation of the machines at 85% across a 16-hour day during peak activity and 8-hour day during lower customer demand periods, 250 days per year, the total annual energy saving use would be:  
3%x 75% x 18kW x 10 machines x (150 days x 16hrs + 100days x 8hrs) = 12,960kWhr.  
Assuming electrical energy costs of $0.08 per kWh  
Total annual saving :  
12,960kWh x $0.08kWh = $ 1,036.80  
The expected cost to replace all motors would be $3,600  
Payback period – approximately 3 years  
Let me know if you need to discuss this further.  

Regards  

Paul  

Production Manager  
APEC Kolath  
Plot No. 38 Kunnapattu Road  
Kunnapattu  
Tamil Nadu 6023105  
India  

Tel: +91-44-3524-0060  
Email: P.Collingwood@APECKolath.co.in  
Web: www.APECKolath.co.in  


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