Archives for April 2018

Decatur Industrial Training on SKF Baker AWA Testing Saves Power Generation Plant Upwards of $1 Million

We covered the entire range of use from data management, data input, testing, and interpretation of test results using the AWA instrument.

Every dollar saved truly makes a difference in today’s environment. However, when we can help put a $1 million dollar figure in front of a savings, it’s news worth sharing.

Decatur Industrial offered to provide training on the SKF Baker AWA (Automated Winding Analyzer) beyond what the manufacture offered. The training would be provided to the customers’ electricians responsible for medium-voltage machines (up to 4,000HP) and technicians responsible for low-voltages machines prior to their upcoming outage. Critical motors would need to be analyzed with the SKF Baker AWA for service acceptance. We held true “hands-on” training with the assistance of the customer supplying several motors from their warehouse.

In the process of testing, we discovered two issues:

A 4000 HP motor failed insulation resistance to ground and the Polarization Index (PI) test, indicating that moisture may be an issue.
A Coal Mill motor was found to have an out of range Pulse –to- Pulse Error Ratio on the SKF Baker AWA. This indicated that the motor had a defect in the turn-to-turn insulation of the coil wires. (Not a Decatur Industrial rebuild!)

What Happened Next:

4000 HP Motor: They were able to dry the moisture from the windings with space heaters to obtain a satisfactory insulation resistance with the SKF Baker AWA instrument training we provided.
Coal Mill Motor: Sent to D.I.E. repair shop for a rush rewind and repair which we were able to accomplish within their outage. With our focus on solutions based reliability, we suggested and made improvements over the OEM winding design.
1. Uprate winding – remove excess slot filler and redesign the coils to provide an 8% copper increase
2. Implemented state of the art corona protection in the stator coils.

Our thorough evaluation of the motor also found mechanical issues. This resulted in machining and repair of both bearing outside diameters to properly OEM bearing-to-housing machine tolerances.

Calculated Total Cost of Ownership Savings:

4000 HP Motor

It could have experienced an immediate failure or a potentially irreversible ground insulation degradation if put into service – both resulting in unplanned downtime and emergency maintenance!

Coal Mill

$8,000 – $16,000 per day (depending on prices and load demand)
PA Fan – $25,000 – $50,000 per day
Plus labor rebuild costs

Coal Mill: $168,000 to $336,000 plus motor repair

PA Fan: $525,000 to $1,050,000 plus the motor repair

Lifting a Motor?

If you or your motor repair facility are planning on moving a motor for installation or repair make sure you use all of the lifting points available by the manufacturer and don’t forget to disconnect the load from the motor. This may be even more important for long frame motors. Using only part of the lift points available or leaving a pump connected to the motor can twist the stator frame resulting in a non-symmetrical air gap between the rotor and stator. This twisted frame will produce elevated 2x line frequency peaks in the vibration spectrum, as well as elevated eccentricity frequency peaks in the current signature spectrum. The worst case scenario may result in premature bearing failure or a rotor/stator rub.

Employee Spotlight: Brooke Thompson, Accountant

Brooke Thompson is one of the newest (and youngest!) members of the Decatur Industrial Electric Team.

Brooke comes to us from Millikin University where she majored in accounting and minored in environmental studies. She also played collegiate soccer.

“I love how everyone here makes you feel welcome and it has truly made my first job experience post-college a positive one.”

Brooke’s responsibilities include Accounts Receivable collections, rebate submissions, month end reporting, cost allocation analysis, assisting our controller, and implementing an ISO 14001 Environmental Management system.

In her free time Brooke likes to go the gym, sleep, watch Law & Order: SVU and Game of Thrones, play video games, and learn new things.

Decatur Industrial Electric Helps an Aggregate Customer Find a Better Motor for their Application

Decatur Industrial Electric was sent in an open drip proof motor for repair. The debris inside the motor was evident immediately upon inspection. After consulting with the customer, we discovered they had been experiencing short motor life with these motors and had not been provided an option to replace the open drip proof with a different motor.

Our experts worked with the customer to explore the best motor options for this application. The motor was driving a water pump in the facility therefore it was our recommendation to install a totally enclosed fan cooled (TEFC) vertical hollow shaft motor which prohibits debris from entering the motor.

A TEFC motor has an initial higher purchase price than the open drip proof motor. However, the extended life expectancy yields a lower cost of ownership. The customer will save on motor purchases, repairs, and unscheduled downtime.

Decatur Industrial Electric has been a top partner and distributor for U.S. Motors for decades. To find out more, visit: https://www.decaturindustrial.com/products/manufacturers/manufacturers-u/