Archives for June 2022

Tips for Installing Motor Test Access Panels

To minimize the risk of being in the vicinity of high voltage when testing your electric motors, your electric reliability team or plant safety management may have opted to install a test access panel. This allows you to test your critical electric motors while running without opening a single cabinet. Although the large majority of these Motor Test Access Panels (MTAP’s) are installed without a problem, always test after installation to insure everything is connected properly. Here are a few tips from the field to validate your installation.

· Verify the voltage input to the MTAP matches the voltage rating of the MTAP. There are four possible MTAP voltage ratings (120v, 240v, 480v and 600v). Under sizing the MTAP voltage rating will saturate the MTAP isolation transformer, resulting in excessive current that will open safety fuses on the MTAP. The most common mistake is installing a 120v MTAP designed for a medium voltage 2-PT open delta secondary into a 3-PT secondary which delivers a 240v signal to the MTAP.

· Verify the output of the MTAP makes sense for voltage and current phase relationships. The MCEGold^® Phasor diagram is the best source for this. I1 should be lagging V1 for a standard induction motor by an angle relative to the motor load. The higher the load the lower the angle between voltage and current. The same applies for phases two and three.

· If connecting a MTAP to a synchronous motor, the current may actually lead the voltage if the synchronous motor field excitation is increased.

· The MTAP current input is looking for a voltage (333mV/amp) from a Current Transformer (CT) with a load resistor. Do not connect a metering CT with a 1-5 amp output directly to the MTAP. If you only have two available current sources to connect the MTAP CT’s to, make sure you select “Missing Current” in the test setup to properly calculate the missing phase current.

· Phase leads are often swapped at the starter or in the motor connection box to reverse the rotation of the motor. This can make connecting the correct current and voltage phases more difficult. If necessary connect one phase at a time and retest until you are able to tell which phase of voltage goes with which phase of current.

Credit: PdMA Corporation

Emma Mallory Awarded Claud Thompson Scholarship

Emma Mallory, a former student at Mt. Zion High School, has received a $1,000 scholarship to help cover educational related expenses for the upcoming school year. She will be majoring in business management at Millikin University.

“Winning this scholarship means a lot to me. I know that college can be very expensive, but I have been saving up and working. This scholarship will allow me not to work as much in college to help me pay for it, but also allows me to focus on my studies,” said Emma. “This scholarship has helped ease some of the financial stress. I just wanted to thank all of the donors of this scholarship for the great opportunity.”

The Claud Thompson Decatur Industrial Electric Scholarship
This scholarship assists students seeking a career in business through the Tabor School of Business (PACE included) at Millikin University or students pursuing engineering technology degrees at Richland Community College. Additional criteria online includes financial need and students who are self-driven and leadership-oriented with a record of community service. High school seniors and college students may apply for the scholarship on the Community Foundation of Macon County website here.

To find out more about our founder, click here.

Creative Engineering and Fabrication Solution Provide Customer Cost-Effective Resolution

This Decatur Industrial customer had a failure on a critical 500HP air compressor. While the compressor was in the shop for a recondition, they wanted to install a new motor in the application. Unfortunately, the compressor OEM had provided a “custom” motor that was now obsolete No motor manufacturer currently builds a “standard” motor to fit in their present base . The customer could not wait for a manufacturer to redesign a one-off motor, which would be extremely expensive and with a lengthy lead time, so D.I.E. went to work on a standard motor retrofit design.

Our technicians worked with plant engineering and maintenance personnel to provide an available motor that would meet performance specifications . We fabricated a steel plating that would adapt the new motor to the base, performed the actual machining of the adapter plates on the customer site to ensure a proper fit, and we modified the junction box to fit customer connections without modifications. This retrofit gave the customer the ability to adapt ANY motor to the fit the application in the future if needed.

The cost to engineer the design and fabricate the existing style base to accept the new motor cost the customer $10,000 – saving them tens of thousands of dollars in downtime and custom motor manufacturing.