Tips to select an electric motor repair shop
Considering the degree to which repair shops differ in skill, equipment resources and procedures, it’s a question that should be high on your maintenance assurance list. Professional shops meet challenging quality criteria and perhaps are even certified by a prominent engineering company. Before sending another electric motor out for repair, measure your service provider against these basic performance indicators.
How does your repair shop perform conformance testing?
State-of-the-art conformance testing is a key characteristic of highly professional repair shops. It is done to help bring motors into conformance with standards set by you or by the shop. The testing can be broadly classified according to two categories: mechanical and electrical.
Best practice mechanical conformance testing calls for vibration spectrum analysis, which requires an analytical vibration tester, and dynamic rotor balancing, which must be performed on a capable and calibrated balancing machine.
Best practice electrical conformance testing includes insulation, wire-resistance and core-loss testing. To complete these tests, your shop needs a winding analyzer with surge testing capability and a core-loss tester. Surge testing is the only test that can detect turn-to-turn insulation degradation — the most common type of electrical failure.
Obtaining this sophisticated testing equipment constitutes a substantial financial investment. Its availability, calibration and use reflect a high degree of professionalism and service capability. All conformance tests must be carefully documented and available to customers upon request. Repair shops should never cut corners when it comes to conformance testing, as they risk returning failing motors to your plant.
Does your repair shop employ written repair procedures?
Written repair procedures reflect the mindset of a well-ordered service operation and ensure that repairs will be completed in the same way no matter which employee services the motor.
Procedures should exist for every step of a repair, and are often documented in the form of a manual. They govern every step of the repair process — from how the shop receives a motor; how the motor is tagged, inspected and taken apart; and where the motor’s parts are stored; to completing the repair, testing it for compliance and shipping it back to you.
Is your repair shop clean, well-organized?
Shoddy work areas are detrimental to the health of electric motors under repair. Airborne contaminants can enter critical motor components such as bearings, seals and lubricants, reducing their reliability and cutting short their service life.
Cleanliness, good lighting and proper storage procedures are essential to facilitating expert electric motor repairs. High quality repair shops assemble motors in a clean, dedicated area, separated from the rest of the shop to minimize the risk of contamination.
Is your motor repair shop certified?
Electric motor repair certification may be attainable from professional engineering companies. The process is intense, demanding and can take the better part of a year to complete. A shop that has achieved certification can claim to be in the top tier of its service category.
A certified shop is strictly procedures driven, employs sophisticated compliance testing practices and has a knowledgeable, experienced staff. Such operations ultimately benefit the shop’s customers by increasing motor reliability and service life.
A case in point
The Washington, PA branch of Integrated Power Services (IPS) recently earned certification status. “We had inquiries about certification from various high value customers,” said IPS service center manager Walt Dryburg. “Also, we were looking for a market differentiator.”
During the certification process, IPS made significant improvements to an already tightly run operation. The shop purchased new instrumentation such as micrometers and gauges for measuring the bore of rotating components and induction heaters that automatically degauss bearings.
“We tweaked our systems to meet the certifying company’s standards,” Dryburg noted. “For example, we put up a wall to isolate our cleaning area from our winding area. This minimizes airborne contaminants.”
Dryburg said the shop’s improvements have increased reliability at its customers’ operations.
“Coal mines measure reliability in terms of ‘rate of availability,’ ” Dryburg said. “Prior to our certification process, one of our customers had an availability rate in the mid-90 percentile. As a result of the high quality repairs we performed on their motors, the mine increased its motor availability to over 99%, saving millions per year.”
|Fredrik Fränding is global manager of SKF Certified Programs, SKF Service Division. He can be reached at Fredrik.Franding@skf.com .|