Becht Engineering Blog

In this section of the site contributing authors submit interesting articles relating to the various services, industries and research & development efforts of Becht Engineering.

Acceptable Practices for High Voltage Motor Lead Routing

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Are Your Wires Crossed?   By Rick Hoffman and Joe Rammage We recently evaluated a 15kV, 5000 hp, induction motor in a WPII enclosure manufactured by a foreign company.  During an on-site inspection of the main terminal box it was discovered that the high voltage leads were touching.  This raised significant concerns about the long-term reliability of the motor. Becht Engineering investigated the issue to determine the industry standards and best practices concerning routing of the motor high voltage leads.    Shielded vs Non-Shielded Cables The National Electric Code requires all cables rated above 2.4kV to be shielded to prevent concentrated electromagnetic stresses from forming between the cable conductor and ground when the cable is in close proximity to a grounded surface.  The addition of the metallic shield smooths out the electromagnetic field eliminating high stress points.  Without it, the increased density of electromagnetic stresses where the cable is in close...
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Reducing Coupling weights in Large Motor Driven Pumps

coupling Pump Coupling Assembly
One of the major issues in designing large motor driven pump applications is minimizing the overhung weight on the pump rotor.  Motor or gearbox drives are designed and sized independently of the driven unit.  They are based on motor frame size and/or gearbox frame sizes and the drive component manufacturer has no information on the actual driven unit.  In motors, the design of engineered motors is based on years of experience and rules of thumb.  The motor rotor is significantly heavier than the pump rotor, thus requiring it to be much larger in diameter than the driven unit size to support the rotor weight and give an acceptable bearing surface area.  It is not unusual for the motor output shaft size to be twice the input shaft size of the driven unit shaft. Size Matters The shaft size differences are basically a product of economics.   It cost money for a motor...
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Root Cause Failure Analysis (RCFA) – A Key Element to Improved Reliability

Becht_Engineering-RCFA
Many companies and organizations have been on the reliability journey for a number of years, while others are just beginning.  There are many elements of a solid reliability program – establishing a reliability centered culture, tracking key metrics, bad actor elimination programs and establishing equipment reliability plans – to name a few.  But, one key element to a solid reliability program, and one that is very important to improving unit reliability metrics, is root cause failure analysis (RCFA). Historically, various methods have been used over time to assist in RCFA – Why Tree Analysis, 5-Whys, and Fishbone Diagrams.  However, one common tool to facilitate and document the RCFA is a Cause Map, or Cause and Effect Diagram.  Cause Mapping is a very flexible platform, which allows utilization for any type of failure investigation, regardless of equipment type, industry, or complexity.  Cause Mapping starts with a primary effect – where the primary...
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Hurricane Harvey Recovery - Methodical Steps to Restart Your Plant

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I personally went through Hurricane Rita and Hurricane Ike during my career living in the Gulf Coast. Restarting our plants after these storms was challenging, home life was miserable without power for three weeks and traveling over 100 miles north to find gasoline, food and water for family and neighbors was time consuming and hazardous. However, this experience pales in comparison to the challenges faced by families and operating companies from Houston to Corpus Christ and beyond recovering from the unprecedented events cause by Hurricane Harvey. In this posting, I identify the challenges faced with our employees and plants as we restarted after these storms. Becht hopes this blog will help you and your companies through these trying times. Many of the personnel at Becht Engineering have been through hurricane recovery , plant restarts and emergency situations. Please contact us if we can help. These important points must be considered as...
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