Motor Repair

Motor Repair

The proper repair of Electric Motors is of utmost importance to A.R.&E. and our customers. The processes that we follow allow us to perform our repairs quickly, while doing so with the highest quality materials, and using the "Best Practices" of the Electrical Apparatus Service Association (EASA). Apparatus Repair & Engineering, Inc. is a proud member of EASA, and is an EASA Accredited Service Center, "Assuring the Efficiency and Reliability of Repaired Electric Motors". These "Best Practices" are based upon the "EASA/AR100-2015 Standard", which you can view and read at this location. In order for Apparatus Repair & Engineering, Inc. to be certified as an Accredited Service Center, the company had to meet specific criteria and prove (through an audit by a third party organization) that they follow the requirements of the EASA/AR100 document. By following these standards, A.R.&E. can maintain the efficiencies built into the electric motor by the original manufacturer. And while this topic page will offer some details of our Motor Repair process, I encourage you to avail yourself of the opportunity to peruse the previously mentioned EASA/AR100 Standard. It's a very educational document.

Motors that come into our facility to be repaired are in varying conditions. Some look like they've just come out of the box, and still others look like they've been run over by a Sherman Tank, and have been prepared for the "junk yard". But that's why we exist... to make them like new (or better).

The first thing to do is clean them up enough to be able to do some initial testing. That may mean cleaning off 3 inches of stone dust just to get to the junction box and leads. And it may also mean using torches and hydraulic pullers to remove a 10 groove sheave to evaluate the condition of the shaft.

After that's completed, we can perform a megger test on the winding to check for grounds, a hi-pot test on the winding to evaluate insulation current leakage and/or integrity, and a surge test to see if the winding has any shorted coils.

Once those tests are performed (and hopefully passed), we can disassemble the motor. Each section is carefully marked with either "center punch marks" or numbers to indicate how components should be reassembled after repair. Any external cooling fan and cover are removed, the junction box is removed, and the end bells are removed. Bearing sizes are recorded and removed. Once the motor is completely disassembled, the individual components are cleaned with a high pressure washer with degreasing solvent. After cleaning and drying, the end bell bearing brackets are dimensionally checked for proper size (based on bearing size) and the values recorded. The bearing surfaces of the rotor shaft are checked and the value also recorded. If any of these dimensional values are "out of tolerance", the component is sent to the machine shop for repair.

Once the stator is cleaned, it is tested with the "core loss tester" to evaluate the "inter-laminar" insulation. The tester current is raised to the proper level (based on the size of he core), and the stator frame is checked for "hot spots". A hot spot indicates insufficient or defective insulation and further evaluation needs to be performed to ascertain whether the motor should be rewound or scrapped.

If the stator needs rewound, it is sent to the rewind department to be completed. You can read our process for rewinding motors on that topic page by clicking this link.

While other work is being completed on the motor, the rotating member is placed in the balancing machine to be checked for proper balance. It will be checked and balanced to industry standards based on the application, speed of operation, and any other "special" requirements that the customer may have communicated to us when the motor was picked up at the customer location. In the balancing stand, it is possible for the technician to check the shaft of the motor for "straightness". The TIR (Total Indicated Runout) of the shaft will be recorded on the job ticket for reference. The value MUST be within industry tolerances based on shaft size to pass our tests.

With everything completed. the motor is ready to be re-assembled. New bearings will be installed on the rotating assembly shaft. Those bearings will be installed using "inducting heating" to expand the inner race of the bearing to allow them to be slid onto the shaft easily. The rotor is placed in the bore of the stator, and once the bearings are cooled, the end bells are reassembled onto the frame and tightened. The rotor is checked to verify that it turns freely, and then any external cooling fan and cover is installed.

Once the motor is totally assembled, a final megger test is performed to verify that no electrical grounds were produced during the assembly process and the motor is connected to our power supply system. It is energized and the voltage is increased to full voltage over a short period of time. Once it reaches full speed, a voltage and current ready is taken and recorded. While running at full speed, the motor will have a quick vibration reading taken to verify proper operation with minimal vibration at full speed.

Finally, the motor will be disconnected from the power supply, taken to the paint booth and painted with a standard "machinery grey" enamel paint, or a specific color and/or quality of paint as required by the customer. Once the paint is dried, the motor will be prepared for shipment to the customer. A packing slip will be printed and it will either be delivered by our truck or the customer will be called and made aware of the motor's availability for pickup.

When you need an electric motor repaired, have it done by the best. Call Apparatus Repair & Engineering, Inc. today. We're here to help...