January 28, 2015
Why Misalignment Draws More Current
By Mac MacCormack
In a previous blog article by Patrick Lawrence “Was Softfoot the Problem” before and after vibration spectrums were taken and the results post precision shaft alignment were remarkable! Apart from contributing to higher vibration levels, misalignment has another adverse effect, increased motor loads! I wanted to find a cause and effect case study that would give me a better understanding. I found a very good one and would like to share that in this blog.
Considering the cost of electric motors alone (between $50 and $100 per horsepower on average, some much higher) and the cost of energy, unscheduled downtime…etc. Precision alignment benefits on the electric motor alone puts money in the bank!
Motor Load increases when there are stresses coming from bearing and unusual mechanical loads. 50% of machinery problems, electric motors in particular are caused by excessive load due to imbalance, misalignment and belt tension. Figures 3, 4 and 5 show the impact of misalignment to motor load.
This technical study was performed by the International Copper Association. I can send you a copy of the full report upon request.