[15mgtar]

do HITACHI VFD run up to 800 Hz?

[Al_The_Man]

The majority are 400hz, you need a specialized one for 800hz.
And also a 4 pole motor that is capable of 24000 rpm.
Al.

[15mgtar]

I am planning to get a 10HP 7.5Kw 24000RPM either 2 or 4 poles spindle motor from either colombo, fimec, or hsd to run @24000RPM I need 800Hz capable vfd. just wondering if the SJ series from Hitachi are capable going upto 800Hz.

[Al_The_Man]

Not according to the specs, you should be able to look up a particular model spec online.
Al.

[15mgtar]

got it Thank you Al
oh btw is 4 poles motor better than a 2 poles motor (given all the specs are the same except the number of poles)?

[Al_The_Man]

Rated torque or HP is rated at the base speed of the motor, so it depends at what rpm point you want your optimum torque to be.
Al.

[15mgtar]

So it doesn't matter wether it is 2 or 4 poles? on the 4 poles model speed is 12kRPM/24kRPM 400Hz/800Hz and the optimum torque is at 12kRPM above that the torque drops (I prefer the optimum torque around 18KRPM for wood)

[Al_The_Man]

There is a trade off or balancing act as a 4 pole motor usually has more torque per HP than its 2 pole counterpart.
You would really need the performance figures at given rpm's for each to make a really concise selection.
Al.

[15mgtar]

Thank you Al.
This next question is off the topic: which is better HSD or FIMEC? or are they about the same?