What are the important factors to choose VFD
All the technical & financial matters are all important ones to choose a Variable Frequency Drive, but the most important is before all to clearly understand what will be the application and process where will be the VFD, note that you can have high quality VFD drive if you use it for fan you'll lose money, efficiency, time to commission...at the opposite if you take a fan VFD for roller mill application it will not work....so 1st thing is to define clearly application and process because it will tell you what you need to control as much as possible and will give you some idea where to go..... important values to control, torque, speed, efficiency & power on network, several single drive, one converter and several inverter, brake, regenerative, cos phi, motion application, open loop, close loop, direct torque control, V/F control, current control....to define the best VFD, before define at best your need and regulation type, the ROI is only important in HVAC system, for big application like tunnel boring machine is efficiency and torque regulation, for Pipelay system is efficiency, harmonic (not acceptable on a boat) torque and speed regulation with master and several slave controls....so clearly 1st application and regulation, then you'll find easily the VFD type....
Few manufacturers make a VFD with simple programming. It is easy to code in a so much application specific capabilities in the chips coming out now. So much room with little cost you may as well fill it up!
I have another aspect to VFD ownership in that once you have made a purchase you have to live with it. All manufacturers will give you some sort of MTBF data and salesmen will promise a long life for their product. But what is a long life for an electronic piece? Look at the installed components and line them up in order of time to fail. You will have capacitors first every time. They will need to be replaced at least once if you want a variable frequency drive to last more than 10 years.
How easy is the VFD to work on? If a VFD failed would I fix it or replace it? Is this a 'throw away' drive that is not expected to be worked on? I take the long term view of ownership.
Few manufacturers make a VFD with simple programming. It is easy to code in a so much application specific capabilities in the chips coming out now. So much room with little cost you may as well fill it up!
I have another aspect to VFD ownership in that once you have made a purchase you have to live with it. All manufacturers will give you some sort of MTBF data and salesmen will promise a long life for their product. But what is a long life for an electronic piece? Look at the installed components and line them up in order of time to fail. You will have capacitors first every time. They will need to be replaced at least once if you want a variable frequency drive to last more than 10 years.
How easy is the VFD to work on? If a VFD failed would I fix it or replace it? Is this a 'throw away' drive that is not expected to be worked on? I take the long term view of ownership.
