Adjustable Frequency Drive 3

[Lan123]

I am trying figure out the NPV of a AFD used with a 100 hp motor. Generally what is the lifespan of a VFD?

Thanks in advance.

 

[ashtree]

Lan123

There are lots of variables that impact on the life of a VFD but 10 years is a good number to start with.
If you have them in a clean cool environment and are well installed and maintained you will get longer.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[jraef]

NPV? Net Present Value? If so, you would need to factor in all of the lifetime costs and the typical MTTF/MTBF of good quality Voltage Source Inverters (as almost all Low Voltage drives would be) is going to be 100,000 hours (about 11 years). In reality however a major component in them, namely the capacitors, are commonly over stressed and fail after about 7 years. Technically you could add an additional 50% of the current cost to replace the caps after 3/4 of the VFD lifespan, but the reality will be that by then, the newer technology drive will be less expensive than repairing the old one, it almost always is. So I just tell people to use 7 years as the expected life of the technology and if you get more, it's a bonus.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[Lan123]

ashtree and jraef thanks for the excellent responses.

 

[M0rt]

Also worth considering that a 10K reduction in capacitor temperature will normally double their lifetime. So some thought about cooling, etc. could save a lot of money in the long term....
Cheers,
Mort