Archives for November 2016

Crane & Hoist Services

Decatur Industrial Electric has been a trusted choice in crane and hoist services for customers for over 60 years.

We are a reliability company so we focus on OSHA compliance.

Some reasons customers use us include:

Inspections and service VS trying to sell you new hoists
Already a trusted partner in motor repair and other solutions
Inspections per OSHA 29 CFR 1910.179 requirements by factory trained technicians
Ergonomics and control system upgrades
Non-destructive testing
Detailed reporting
Preventative and predictive maintenance
Training of your personnel

Coal-Fired Generating Plant Experiencing Repeated Failures

“It’s Always the Motors Fault” : Decatur Industrial Breaks Down the Myth

We’ve seen it before – a plant experiences repeated motor failures and calls in a motor shop to fix the motor. The only issue is sometimes the problem lies elsewhere.

Your average motor shop will repair the motor and send it back into the plant. The problem with that scenario is the root cause of the failure is never identified which means continued downtime and high repair costs for the plant. As a Strategic Partner in Reliability Solutions for our Customers, Decatur Industrial goes beyond repairing the motor and completes a 360 degree root cause failure analysis.

This type of strategic approach allowed us to help a large coal-fired generating plant that had been experiencing repeated drive motor failures. Decatur Industrial worked collaboratively with Customer Engineering to identify the contributing factors of the premature failures and short life-span of the drive motors with the goal of eliminating emergency downtime and catastrophic equipment failures.

Findings disclosed structural looseness in the foundation and hardware that secured the motors and blowers. This looseness contributed to misalignment and excessive vibration levels – both of which reduce life-span of motors and drive components. These findings allowed the customer to take corrective actions and implement predictive maintenance and reliability practices.

These findings amounted to hard cost savings as the customer had been spending $140,000 annually on repairs of motors and blowers due to failures that had nothing to do with the motor integrity.

Motor Tip: Change from Baseline

We know phase resistance of an electric motor can change drastically with temperature. As temperature rises the resistance rises as a result of copper having a positive temperature coefficient. However, on a three phase motor even though the phase resistance values change with temperature the balance of resistance between the three phases should not change. For your medium and high voltage motors (> 4kV) the balance of resistance is often very low (<1%). In fact, it is quite common to see values of imbalance in the one-hundredths of a percent (ex. .03%). The standard MCEGold balance of resistance setpoints for a medium voltage motor is 1% (caution) and 2% (alarm) so a baseline balance of resistance of .03% would have to increase ~3000% to reach the 1% alarm setpoint. Therefore, it is important for you to consider establishing a change from baseline alarm setpoint for your balance of resistance in these situations to alert you to large changes in the circuit condition.