We get it. Preventative maintenance is costly – both in manpower and hard dollars. However, the cost of NOT doing it can be extremely more expensive.

During a scheduled preventative maintenance call at a customer site, a Decatur Industrial technician was inspecting a DC motor for brush wear, condition of the brush springs, and the state of the commutator. The commutator had extensive wear in the brush path. The brushes facilitate the flow of current into the armature so when excessive wear occurs, the motor has a more difficult time maintaining speed and output.

The commutator had a row that was not being used so we removed the spacer to adjust the brush holders onto a new brush path. This allowed the customer to continue using the motor and prevent it being pulled for reconditioning at a cost of $35,000.

Decatur’s expertise with hollow-shaft, vertical pump motors allowed this customer to get a modern energy-efficient motor replacement quickly rather than waiting weeks to repair the motor. Motor suffered a CATASTROPHIC FAILURE!

When a piece of critical equipment fails, in this case, a Louis Allis 250hp hollow shaft vertical pump motor, decisions must be made quickly.   

When the emergency call came in, D.I.E. picked up the motor and followed with an immediate evaluation. Ultimately it comes down to whether the motor should be repaired or replaced, and the time associated with each option. The motor was an obsolete, older design that historically was always repaired due to the complexity of replacing the motor with new.  Changing to a newer design capable of the same electromechanical performance and mounting/coupling requirements was a daunting challenge for previous motor repair vendors.  Rewinding the motor stator and performing mechanical repairs would take a week or more depending on the variables, all while working around the clock with a significant dollar investment.

Our team was able to identify a current new production motor that would mount in this application and would require only one modification.  The motor section of the pump shaft had to be shortened and re-machined to match the height of the new motor’s coupling height enabling the motor coupling to drive the pump shaft and pump.  Decatur provided the new NIDEC/ US Electric 250hp vertical hollow shaft motor’s engineering data and directions to follow in shortening the motor section of the pump shaft.  The motor was delivered via courier within the following day of the order.  The customer was able to utilize a local machine shop to make the modifications on the pump shaft section to be ready for the motor’s arrival so that the installation could immediately occur.

This solution saved tens of thousands of dollars in lost production and emergency repair costs that would have exceeded the cost of new. In addition, Decatur’s team supplied the pertinent key information for the customer to accomplish modifications and enable the installation to promptly begin upon the motor delivery.  The result is a new motor replacement that provides greater efficiency through reducing power consumption and cost of this critical need application. 

How Could a 200 Horsepower Motor Not Be Worth Repair?

It happens. There are times when our service center must tell a customer that their 200hp motor is just not worth repairing.  Extreme damage from the motor failure may make the motor not economical to repair (NER); however, there are other times when it’s just not a good business decision to repair.

Our goal is to provide our motor owners with a reliable repair that is as good as new, or better in many cases. In this case study, the motor had suffered many previous insulation failures to ground and it absolutely could have been rewound economically.  However, even though the damage was not visible, proper coreloss testing revealed the laminations were shorted. When this occurs, the motor loses performance, efficiency, and will eventually suffer a failure in the stator hot-spot area.

This customer at first didn’t understand why we recommended recycling the motor because they had it repaired by another shop several times.  However, after an inspection review with the customer of the test results and quality concerns, the customer researched the motor history and found that the motor had been rewound not only several times, but also less than 6-months ago.

As Strategic Partner’s in Reliability Performance, it’s D.I.E.’s job to help our customers make good business decisions with their critical motor assets. Decatur Industrial now offers the full range of Toshiba motors and drives and was able to provide the customer a new energy efficiency “drop in” replacement Toshiba motor solution.

Hidden Damage = Poor Reliability!

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It is time to get motors ready for the long hot summer. For many this includes cleaning their critical motors and other equipment for the upcoming summer months.

We generally recommend preventative maintenance during a regularly scheduled outage. Fall and spring is another good time to have it on the calendar.

Top tips for maintaining your electric motors:

1. Develop a general maintenance and cleaning routine
2. Check the motor’s lubrication
3. Regularly inspect the bearings
4. Reduce or eliminate vibrations
5. Inspect the rotor and stator
6. Record your findings

Cleaning the exterior of a motor, including the can and fan cover will help extend the life of the motor.  See pictures of motors pulled from a customer’s recent spring cleaning!