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Eddy Current vs. VFD Technology


There is more than one way to change the speed of your electric AC motor, and some of the most commonly used methods are eddy current drives and variable frequency drives (VFDs).

The Need for Adjusting Speed

Not all electric motor applications need to run at motor's standard speed. An application may need more torque (which requires a reduction in speed) or more additional speed (which in turns means a reduction in torque). A motors' speed really should match what the application needs, and when they do not, there are significant losses in efficiency. When you consider some experts' estimate that 65% of industrial power consumption comes from electric motors, you realize how much of an impact this can have on your overall plant efficiency and energy consumption.

However, if a motor is not a perfect match to the loading needs of the application, the speed and torque can be adjusted through the use of system devices (valves, dampers, etc.). That approach, however, is not ideal and still leads to wasted power and inefficiency -- which is something you normally try to avoid. An alternate, more effective solution is the use of eddy current drives or variable frequency drives (VFDs).

Why A Quick Answer Isn't Always the Best Answer


A philosophy of our company has always been to help whenever we can. We have the resources, experience, and mindset to bring solutions to our customers on almost every motor related issue. Often times we are asked to bring solutions and answer questions to problems in breakdown situations without all of the facts. These breakdown situation questions can either be on motors that have been sent into our shop or motors that are still in-service. 

Is Your Motor Repair Shop Making You Dependent on Them or Teaching You?


Just like in our everyday relationships, we tend to stay with a person or business because we have been “using them for years", but are they helping you or do you feel obligated to stay with them?  Have you been using the same car mechanic forever, but your car still has the same issues? 

Case Study 5500HP, 13,200v, Synchronous Motor: (Part 8) Final Assembly and Installation


In the final post in this 8 part case study series, you will see Todd Hatfield explain the final assembly of the 5500HP, 13,200v, synchronous motor in the clip below from a presentation given at the 2018 RPM Symposium. 

The presentation below covers:

  • Assembling the rotor to the adapter base with the stator

Case Study 5500HP, 13,200v, Synchronous Motor: (Part 7) Adapter Base


For part 7 of this series, Todd Hatfield will be explaining the process of creating the adapter base in the 2 videos below. Video one explains the engineering of the adapter base design, while the second video explains the process of mounting the stator to the adapter base.

Video 1 describes:

  • Creating a CAD drawing to ensure the adapter base design was scaled to fit into the concrete pit

Case Study 5500HP, 13,200v, Synchronous Motor: (Part 6) Stator Redesign and Rewind


Below is a 2 minute clip of an hour long presentation given by Todd Hatfield during the 2018 RPM Symposium. Part 6 of this 8 part series focuses on the redesign and rewind of the stator for the 5500HP, 13,200v, synchronous motor.  

This video will describe:
  • The new engineered stator winding design and CAD drawing

Case Study 5500HP, 13,200v, Synchronous Motor: (Part 5) Electrical Design of Rotor


In part 5 of this case study, Todd Hatfield will be reviewing the electrical design of the rotor. Below is a short 3 minute video showing the steps involved in creating the new coils for this 5500HP, 13,200v, Synchronous Motor's Rotor.

 The video below will discuss: 

  • The decision to keep the coil design and duplicate it or to come up with a new and improved design

Case Study 5500HP, 13,200v, Synchronous Motor: (Part 4) Mechanical Design of Shaft and Rotor


Below is a 10 minute segment from an hour long presentation given by Todd Hatfield. In this clip, Todd Hatfield will go over the mechanical design of the shaft and rotor and how HECO assembled it all together.

The presentation below discusses:

  • Design assessment to see how to fit a larger shaft in the rotor and re-configuration

Case Study 5500HP, 13,200v, Synchronous Motor: (Part 3) Electrical & Mechanical Redesign Engineering


In part 3 of this case study, Todd Hatfield will be discussing how HECO re-engineered the electrical and mechanical design of the surplus motor to match the 5500HP, 13,200v original motor.

This 13 minute presentation will go over:

  • On-site laser measurements using FARO technology
  • Determining challenges such as
    • How the spare motor would fit into the existing pit 

Case Study 5500HP, 13,200v, Synchronous Motor: (Part 2) Evaluating Surplus Motor Options and Initial On-site Application Review


For part two of the series, Todd Hatfield will be reviewing the dismantled surplus motor and explaining some of the on-site findings for the 5500HP , 13,200v, Synchronous Motor.

In this video segment, you will see:

  • The replacement motor's shorting ring and it's unique placement on the motor
  • Data collected on the replacement motor's stator and rotor
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