Hi, new to PWNCNC. I tried to search but didn’t find an answer.
Does anyone know the min rpm on the 2.2kw 4 pole 800hz spindle?
In manual mode I can get my VFD to show a speed as low as ~250 RPM. With the MASSO the lowest RPM is ~500. I assume this is due to the VFD interpreting the PWM from the MASSO. In both cases I could stop the tool holder spinning with my fingers, so not much torque.
What operation are you trying to do at low RPM?
Just wondering what I can do with mild steel.
Hey Fortune3976,
here I mentioned spindles with low speed high torque, which means more magnetic poles, could be used to mill steel. However when a user got a four-pole, 12,000 rpm spindle from PwnCNC, it turned out that it had not more torque at low speed than the average 24,000 rpm spindle.
If you want to mill steel, the best thing would be a synchronous motor as spindle, which can have extreme torque at speeds down to 1000 rpm or even 100 rpm. VFDs like the Omron MX2
or the Hitachi WJ200 or its successor, the Hitachi WJ-C1, can drive both asynchronous induction motors like the usual spindles as well as synchronous (permanent magnet) motors like the DATRON Syncro spindles. A rigid machine like this DIY Mini-VMC made of concrete is better suited for milling steel than a gantry-type cnc machine.
PS: It seems however that there are different four-pole spindles available from @Daniel. See also this hint and this hint
I don’t remember ever selling a 12k rpms metalworking spindle. If I did and i forgot as that would definitely have to be a special order. We tried to split the difference when it came to our metalworking 4-pole motors. So we’ve asked GPenny to produce our metalworking motors at 24k which definitely reduces it’s low-speed torque capabilities.
Nearly all of our customers are woodworking dabbling in metal. So they’d still need the full 24k speeds for some/most jobs. Due to this we’ve opted for the higher speed rpms vs the lower speed torque.
All this said we are still selling GPenny motors and although they are the best in China, they’re not the best in the world. There are some German spindles that will absolutely run circles around GPenny all day long but they carry with them a much higher cost.
All this said, thank you Aiph5u for keeping the conversation going with the facts and providing the details that customers need to make the right decision for their needs. Keep that up!!