Variable Frequency Drives have quickly become one of the most effective ways to conserve energy in many motor driven applications. They have a high upfront cost, but can save you a lot of money in the long run if they are well maintained. This article will address some of the most important things you can do to extend the life of your drive.
Keep it Clean
Keeping an expensive item clean and protected from the elements should be a no-brainer. All VFDs should be kept in a cabinet to ensure a long life. We expect a VFD to last 3-5 years if it is mounted in the open with no shelter from dust and debris. If that same VFD was housed in a NEMA 1 or NEMA 12 rated enclosure, we would expect that VFD to last about 20 years, given it is well maintained and looked after.
Every time you perform maintenance, or even just open the cabinet to look at your VFD, you should be cleaning out any visible dust and debris. For the cabinet and heat sinks, you can use compressed air to blow the dust and debris away. For the more sensitive equipment, you should be using a vacuum, or a microfiber cloth to avoid building up static electricity. If any oil is visible on those sensitive parts you can usually use rubbing alcohol on a microfiber cloth to remove it. Be sure to check your specific manufacturer’s recommendations to see if this is an approved cleaning solvent.
Keep it Cool
Overheating is one of the main reasons a VFD will fail, but it is often easily avoidable. Make sure that along with cleaning out the cabinet of any visible dust or debris, you also pay special attention to the fans and heat sinks. Debris accumulation in these areas can quickly cause overheating issues for your VFD.
Keep the ambient temperature at manufacturer recommended standards to ensure that your fans are not overexerting themselves in order to keep your VFD cool. Overexertion can lead to fan failure that if left unaddressed for even a short period of time, can lead to overheating of your VFD.
Keep it Dry
Another very important aspect of VFD care is to keep it extremely dry. Your VFD is essentially a very expensive computer that controls other very expensive equipment. And just like you wouldn’t want to let your laptop sit out in the rain, you don’t want your VFD to sit in any moisture for any period of time. Moisture is the number one enemy of electrical equipment. Moisture causes corrosion and short circuiting of the most delicate parts of your VFD. Usually, if moisture has found its way inside your VFD, you are too late to prevent failure.
If your VFD is in an area where you are worried about condensation, a NEMA 12 enclosure, close observation, and a space heater may be needed to combat moisture.
To keep your VFD in good working condition, inspecting the most critical elements regularly is key. With routine maintenance performed by a well-trained and knowledgeable technician, you should be able to remedy small issues before they become critical and cause unscheduled down time.
Ensure Connections are Tight
During maintenance your technician should be checking all connections for any looseness. Loose connections can cause hot spots in your cabinet, which can lead to electrical arcing. To ensure connections are tight, they can use an infrared camera while the drive is running to see if there are any visible hot spots. However, this method is not foolproof. Another way to check for loose connections is to tug on each connection with your hands to see if they feel any give. If they do, they will tighten the connection to the manufacturer recommended specifications. Over-tightening your connections can lead to compromised screws, which can lead to loose connections down the road.