VFD, rotary, or both

[garymommsen]

My application is a 3 phase, 300 hz, 12 hp router spindle along with a 75 amp sander. They will never be run at the same time. I only have single phase available. I would appreciate any comments on what direction to go.
Thanks, Gary

 

[jraef]

Is the sander 300Hz as well?

JRaef.com
Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[itsmoked]

I would not hesitate to go with the VFD UNLESS the whole machine needs 3ph then a rotary may make more sense since you cannot feed the 'machine' from a VFD.

Whoa, what are you talking about 300Hz???????????

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jraef]

That's why I asked. If you go rotary, and the sander needs 60Hz, you will STILL need a VFD for the router. That may still be a better plan anyway, I'd be willing to bet the router isn't 75A!

JRaef.com
Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[garymommsen]

To clarify my application: I have a 12 hp, 300 hz three phase router. I also have a belt sander that is three phase and draws 75 amps. They never are runing at the same time.
Thanks, Gary

 

[jraef]

Huh. You restated the same information adding only the HP of the sander. I guess you want us to ASS-U-ME that the sander does not require 300Hz then and that the voltage is going to be 240VAC 60Hz? I am only ASSuming 60Hz because you used the term HP instead of kW, so I can ASSume you are in N. America somewhere.

Making those assumptions, get a 60Hz RPC for the total load (your HP was meaningless without voltage, but again ASSuming it to be 230V, roughly 29A), maybe 120A continuous or so. Then use a VFD to provide the 300Hz for your router. To do the entire job with a VFD, even if you only run one at a time, would mean buying a 150HP 230V VFD, NOT cheap! You would also run the risk of accidentally applying 300Hz to that sander if you forget to change the limits one day, which would likely destroy the sander!

Another alternative would be to get an RPC for just the sander, then use a VFD to do both the phase conversion and high frequency. The caveat to that is that the VFD would still need to be doubled in size to do the phase conversion, so a 25HP VFD for that 12HP motor.

JRaef.com
Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[itsmoked]

hahaha!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com