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.
Awesome info. Easy cost justification.
If there not time to do it properly the first time,
when is there going to be time?
Years ago we, engineers designed machine support systems by rule of thumb and other weak methods. At that time our saying was; we never had time to do (design) it right, just over. We didn’t know any better. We had vibration and alignment problems; I find the problems still prevail and and will continue until the foundation system is understood and designed accordingly. There is a very understandable and precise method of designing dynamic systems to control the rigiity of the system; thus controlling vibration and alignment.
Milwaukee, WI. 414-964-3034
Need a full copy for current measurement with equation
Krishna, I will email you a copy of the study.
Could I get a copy of the study too?