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Evaluating and Drafting Motor Repair Specifications for Improved Reliability

Reliability, MTBF (Mean Time between Failures), downtime, costs, safety, efficiency, and standardization have pushed documented motor repair specifications and internal motor repair facility’s repair processes to the forefront in today’s industrial environment.

Reliability, MTBF (Mean Time between Failures), downtime, costs, safety, efficiency, standardization have pushed documented motor repair specifications and internal motor repair facility’s repair processes to the forefront in today’s industrial environment.   Many motor repair facilities are ISO Certified and have taken the proactive approach to identify the areas of improvement in their processes.  Evolving through ‘trial by fire’ is still too often the primary training process for both the customer and motor repair facility; learning through painful warranty issues and the findings of the Root Cause Failure Analysis.

Plant reliability personnel create repair specifications to minimize failures. “When equipment failures occur that cause fires, chemical emissions, injuries or other serious issues, the repair processes impacting the equipment and its repair specifications will be put under a microscope.  The ultimate goal of a repair specification is to control the cost of the repair while maintaining the reliability of the motor and hopefully satisfying the repair wish lists for each department.” said Jim Williams, CEO of Bradleys, Inc.   A typical electrical engineer will focus on turn and ground wall insulation in the coils, winding temperature, electrical testing, core testing and other typical electrically related issues. A mechanical engineer will focus on balancing, vibration, mechanical clearances, run out tolerances, repair processes and other mechanical related issues. A reliability engineer may want to push all facets of repair to extremes to get the most reliable repair, without much consideration for costs.

Even when a Request for Quotation (RFQ) is accompanied by a detailed 20 page repair specification, the level of repair may still be different.  A very common scenario occurs when a RFQ is released to three repair facilities by the purchasing agent. Two of the repair facilities provide only sporadic or overflow work for the customer.  The third facility, which is the customer’s preferred motor repair shop, reviews the 20 page repair specification, along with five additional pages of repair specifications that have been added over the years to satisfy the customer’s particular concerns.  The customer is generally unaware of the existence of the extra repair specifications, which add additional material and labor to the repair.  The purchasing agent simply notes that the preferred facility’s quote is the highest.

Let’s assume that after five years of service, a new motor needs to have the ball bearings replaced. For this illustration, we will agree 5 year performance of the ball bearings is acceptable by everyone’s expectations. The preferred repair facility replaces the bearings and follows the repair specification provided by the customer, along with the repair shop’s quality standard; the motor runs another 5 years and everyone is satisfied.

The ‘trial by fire’ scenario is illustrated as the following: The motor is transported to a repair facility that repairs the motor to the specifications provided by the customer. It performs for only two years and the bearings fail. The motor bearing life has exceeded the typical 1 year warranty, but the customer’s expectations were that the motor run for a minimum of five years. The customer reviews all facets of bearing handling, lubrication, cleanliness and installation. The customer identifies the fact that the repair facility’s process for installation is to heat the bearings on an older induction heater that does not demagnetize the bearing. The specifications are not specific about how a bearing is heated.  Since bearing manufacturers recommend that bearings be heated by a temperature-controlled demagnetizing heater, future repair specifications are subsequently modified to include this specification.  Had the original specification included that the bearings be heated on a temperature-controlled demagnetizing heater, the bearings may have performed for five years, in accordance with shop and customer expectations.

Oftentimes, repair specifications result from a customer’s frustration in dealing with a motor repair facility with limited capabilities and knowledge of adequate repair techniques.  As an example, one repair specification states that a motor shaft will not be straightened: it must be replaced. Since the beginning of the industrial age, shafts for many applications have been repaired and straightened. There are many situations in which a bent motor shaft can be successfully repaired and provide like-new service. In every case, to include a blanket statement such as this will drive up repair costs and prolong the time the motor is out of service. There are also applications in which the shaft’s application is at its design limits. In these few cases, any repair that compromises the shaft’s reliability is a good argument for replacement.  

The overachieving preferred motor repair facilities have a real dilemma when it comes to staying competitive in the typical market place. Generally, the quoted price for a simple work scope and/or specification will be a bare bones quote and will not provide a repair of any real quality. The industry practice is to make it up on the add-ons. If a customer is going to rely on price alone to award motor repair contracts, the repair facility must decide which of their processes will be trimmed to stay competitive. In other words, the repair facility must reduce its level of quality and possibly the product’s reliability, to remain competitive.     

A customer can use a better-than-average standard repair specification, such as IEEE 1068, which was driven by the Petrochemical industry. To a great degree, adherence to a standard such as IEEE 1068 creates a more level playing field as one repair facility competes against another. Due to their specialized industrial markets, many repair facilities have developed processes that far exceed the minimum requirements of even a good standard, such as the IEEE 1068.  “Creating your RFQ with adherence to such specifications as those found in  IEEE 1068, will ensure minimum standards are met by all bidders, ” said Williams.

Leading motor repair facilities with a proactive quality system will eventually exceed even the best repair specifications. Shops that regularly service the petrochemical and mining industries may excel in mechanical areas because of their experience with 3600 RPM horizontal and vertical motors. A shop may create a comprehensive inspection process to minimize vibration problems and increase reliability on these high speed machines.

Some motor repair facilities may take their winding process, testing and redesign well beyond the average specification. The repair shop may incur the additional costs of these items, recognizing the long term benefit and added reliability. The shop may pass the cost on to the customer at a slightly increased price or accept slightly less margins. If the customer is strictly price-driven, the shop must decide to reduce quality enhancements and price to compete.

It is critical that your repair specifications are detailed to ensure accurate quotes from all motor repair shops. Touring repair facilities, researching shop capabilities and equipment, as well as creating standards for repairs and testing in your RFQ will impact your motor’s future performance.  

Bradleys, Inc. provides electric motor repair and consulting, rewinding, horizontal and vertical motor load testing, CNC machining, climate-controlled asset storage, field services and new motor sales to industry leaders throughout the U.S. and internationally. The company’s state of the art 110,000 square foot facility is located in the heart of South Texas, just sixty miles from the Eagle Ford Shale, in Gregory, Texas.  Bradleys is ISO 9001:2008 certified, a TECO Westinghouse Award Winner for several years, and was named a finalist for Baylor University Texas Family Business Award in 2013.  The company has served the refining, petrochemical, manufacturing, pulp and paper and mining industries for over 85 years.