VFD
- Thread starter rose1981
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
"Needs" is not the right word. Both options are viable, and the decision is a designer's prerogative. The trend towards using VFDs has been going on for a long while. I seldom see an equipment schedule from our mechanical engineers that does not show VFD for every motor over 2 HP. Cost is one consideration, of course. The impact of the starting transient on the distribution system is another, especially for very large motors. The influence of the harmonics that a VFD introduces on the electrical system is still another.
Welcome to the forum.
Welcome to the forum.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Usually the mechanical engineer will specify if a VFD is required.
JoeStillman
Senior Member
- Location
- West Chester, PA
Using a VFD usually means the controls will be complicated. They are not for switching motors on and off. If the controls are just a thermostat, use FVNR. If the controls are some kind of proportional signal, you're in VFD land. If all you want is low inrush current, a reduced-voltage starter is the way to go.
When you said "condensers" I had to wonder what type. Many of them come with their own starters. You definitely need to have more of a conversation with the mechanical department.
When you said "condensers" I had to wonder what type. Many of them come with their own starters. You definitely need to have more of a conversation with the mechanical department.
- Location
- Illinois
- Occupation
- retired electrician
Assuming the system has been correctly designed from a mechanical standpoint and that the system does not need variable speed, there is no reason to use a VFD. It will just add to the installation and operating costs.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
- Status