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Decatur Industrial Electric recently received an emergency field service request from a steel industry customer to troubleshoot the controls and inspect a 750HP, 900 RPM M-G set that would not start.

During inspection we found that the generator portion of the M-G set had serious issues with the interpole insulation. Between the core iron and the coils, the core insulation had completely disintegrated and turned to powder.  Additionally, the line leads on the motor portion of the unit were oil soaked and swollen. It was determined that the unit needed to be removed and repaired at Decatur Industrial because it was impossible to properly test the unit in its current condition.

Upon arrival at our shop, we completely reconditioned the M-G set, which included removal of all the interpole coils, reinsulation, and a VPI treatment. We also rewired the DC internal connection and releaded the AC motor stator.  Finally, we were able to properly troubleshoot the control problem and repair the faulty contacts.

Although we were unable to initially troubleshoot the controls due to the deteriorating insulation on the generator side of the unit, we saved the customer the cost of a complete M-G set rebuild which can cost upwards of $200,000. They paid less than half of that amount for our repair.

See pictures at the bottom of page!

It was becoming routine – every few months a 5HP motor running an important application would need replaced due to unplanned motor failure! A small motor was causing downtime, maintenance expenses, and frustration with the team.

Instead of just selling a replacement, the Decatur Industrial team of experts investigated the situation to understand WHY the motors were failing at a rapid rate and see if there was a better motor solution for the application.

Upon review, it was discovered that the area where the motor sits is frequently washed down since the material being processed in the location is highly corrosive. Therefore, we recommended a Siemens IEEE 841 Severe Duty 100 motor with a copper rotor as opposed to the Brand X they had been using. This would also allow for long-term energy cost savings and better reliability.
The Siemens motor was 26% less expensive than their past motors and it had two bearing isolator seals to help keep water and contamination out. That results in a savings of $5,000 in direct expenses plus the savings in downtime and emergency maintenance. Also, for every extra year past the two years the new motor lasts provides an additional savings of $3,500.

Below are pictures of the endbells (bearing housings) on their old motor, with contaminates still in them.

Decatur Industrial Electric performs DC and synchronous motor PMs on a routine basis for an industry leading paper mill. Our tracking and trending of electrical testing revealed that a 2,000 HP synchronous motor had degrading insulation and resistance to ground readings over time.  Our reliability specialists, during a scheduled plant outage, inspected and dry ice blasted the motor onsite. The resistance had huge improvement.

Dry ice blasting is an effective and quick way to clean electric motors. It also allows the equipment to be cleaned in place and in an environmentally friendly manner. And, because dry ice converts to gas, there is no fluid or water residue. As a result, there is no disassembling of electrical components or equipment.

Through this method, we were able to clean the motor on-site to the point where it was able to stay in service and a spare didn’t have to be installed. The PM testing saved over $250,000 because the motor did not run-to-failure causing unplanned downtime. The on-site cleaning altogether saved downtime, equipment change out costs, and repair costs.

Decatur Industrial Electric was one of three companies who had the opportunity to bid on a new large motor for a power generation facility. The customer was looking to replace an old open drip proof motor.

We did not want to simply quote a replacement; but wanted to look at the application and see if there was a better motor solution.

In the pursuit of a replacement motor, our team reviewed the following:

1. Review more efficient and newer technology available
2. Changing the application to a TEFC (Totally Enclosed, Fan cooled) -due to the motor operating environment
3. Performance data, including torque requirements for blower

After the review, we proposed for purchase a TEFC that would fit the present base and meet blower torque requirements. This motor was a standard stock item and was on-site quickly, but it also alleviated the requirement of needing a spare being stocked.

The customer awarded Decatur Industrial the job, which included the purchase and install of the new motor along with a new coupling. Even after the purchase and installation, the savings to the Municipal was $21,551 lower compared to other bids. Plus, the customer did not have to invest in a spare.

The next time you need to replace a motor, give Decatur Industrial Electric a call. We partner with you to see if there is a better motor solution for your application that over time will save you Total Cost of Ownership.