Tips for restarting your VFD after lockdown

Living in a Covid-19 world with restricted guidelines, the following procedures have become the order of the day.

As more and more plants are cranking back up to full capacity after lowered production or sitting idle, now is the time to check the condition of machines. 2020 will always be remembered as the year of social distancing. Keeping a healthy space between employees and wearing masks have become the order of the day in a health-conscious society fighting a pandemic. Many production settings were also impacted with some assembly lines shutting down for long periods during lockdown while other facilities were left wholly idle. According to Jason Wellnitz, Product Marketing Manager for Yaskawa, restarting equipment after a long shutdown need not be a headache, but it is important to consider the condition of machines in plants. “Performing preventative maintenance on your electrical equipment before powering them back up is an important step to a smooth startup and in ensuring machine longevity,” he states. “Variable frequency drives (VFDs) are commonplace on motor-operated equipment for several reasons. One of the most noteworthy reasons is the reduction of maintenance costs, but VFDs also have a

unique maintenance cycle.” Wellnitz, who authored a recent paper on VFD preventative maintenance, says it should be performed by a trained professional and should typically consist of four steps - visual inspection of key components, checking power connections, verifying component life and reforming capacitors.

Visual inspection

Wellnitz advises looking for signs of condensation, corrosion, dust and foreign objects when doing a visual inspection. This should be done thoroughly and could even involve finding an insect or two in the equipment. “Catching these simple issues can often be corrected onsite and save considerable repair expenses.” It is also important to check for heatsink and fan obstructions, while enclosure air filters and gaskets must not be overlooked.

Power connections

Loose connections are a hazard and can easily be avoided by making sure there are none.

“Power connections can loosen with heating and cooling cycles. Loose connections can overheat and cause VFD faults, tripped branch circuit protection, or premature failure. The inspection should verify all power connections meet the torque specifications of the electrical equipment OEM(s),” says Wellnitz. Following proper torque specifications is also critical and going the extra mile to check the power wiring for hot spots is advisable.

Component Life

With VFDs designed to operate maintenance-free for defined periods depending on the manufacturer and the model checking up on component, life is