Here You Go.


Replacing a VFD? Consider a Retrofit.


Before_After_VFD_RetrofitMaintaining a plant can be costly as failures can and do occur. We plan for these situations in our budget meetings and look at historical spend data to set aside an appropriate likely amount to cover these costs. It’s smart planning. 

Finding ways to spend wisely without sacrificing quality or reliability can be a challenge but there are definitely ways it can be done. One thing to consider is a retrofit option when replacing or upgrading VFD’s (Variable Frequency Drives). In most cases a new drive can be installed using the existing wiring and enclosure.

Take for example this wastewater treatment facility in Michigan, they have roughly two dozen SquareD Altivar drives that are 20 years old, are no longer supported, and parts are scarce. The costs were compared between having new systems installed and a retrofit into existing structure and the savings were substantial. The Altivar drives were pulled and ABB ACS310’s were wired in their place. The new drives communicated flawlessly with no issues connecting to the existing SCADA system. The ABB keypads were fixed to the cabinet and finally the SquareD badges removed and now the facility is running on much newer technology with full device support for a fraction of the cost.

In another example at a municipal water plant there were continuous issues with the synchronous exciter blowing resistors. Using the existing enclosures, since they had ample space, 28kVA sync transformers and 120VAC control power transformers were added in, as well as a Benshaw MX2 SEP Chassis and smart keypad on a subpanel as the new starter. With the new fusing, relays, disconnects and fan added to the existing structure we had a system that performed perfectly and a fraction of the cost of running all new components.



From small single horsepower controls to starters and even medium voltage drives, as shown it can be wise to seek out someone capable of completing the job as a retrofit. Be sure to ask the right questions such as if it’s possible, what the cost savings would be, and if your contractor can provide continued service once the install is complete. This is a great way to think outside the box for cost saving measures without cutting corners.

 Subscribe to the HECO blog


Justin T. Hatfield, CRL, CMRP

HECO - All Systems Go


About the author:

Justin T. Hatfield, CRL, CMRP  is the President at HECO - All Systems Go. He is responsible for Electric Motor & Drive Sales, Electric Motor & Generator Repairs, Spare Solutions, and Predictive Services.  Justin is a Certified Maintenance and Reliability Professional (CMRP) by the Society of Maintenance and Reliability Professionals (SMRP). HECO is an EASA Accredited Service Center for Electric Motors as well as a provider of predictive maintenance & reliability services and products throughout the United States.


Subscribe to Email Updates

Posts by Topic

see all

Recent Posts