I may be wrong but I’m not sure it converts it to DC, because That was what I thought it did initially, and then I got the impression it didn’t. I need to ask Colin, but he may have a different type of vfd.
No, I can actually get a 2.5 kW for the same price. I’ve just had this one when I thought that I’d need it for my Ox.
Well, I was wrong. About a $50 increase
@George_Allen it must convert to DC otherwise it would not be able to shape the waveform. the process will be
- mains AC in.
- full rectifier to floating ground DC.
- boost converter (with probably a pwm chop up to a few thousand kHz)
- logic to reduce down to the desired peak voltage
- inverter with variable frequency to pump out AC at the right RMS.
i can’t see that there is another way to do it.
Also, if it didn’t do this, why are they called inverters!
The basics…
there you go. diode rectifier with a big smoother cap and inductor.
Okay. Now to overcome the challenge that is the level of rigidity in my axes. I may opt to try a build like the one I just posted.
It’ll work, those inverters are notorious for failing. Everyone says that, mine did too.
@Paul_Shaw I can tell you design/building power drivers are not for the faint of heart. I am on my 3rd proto for the standard spindle motor. Lots of care needed in layout and component selection :).
@donkjr I think I may have just discovered that in the process of building something as small as this 3d printer. For about two weeks I’ve been trying to troubleshoot why some motors aren’t working because they are Nema 17s, but looking at a (hidden) page on the reprap site I may have located a source, though none from the 3d printing groups have mentioned it. The model of Nema I purchased JK42HS40-1704-13A, though listed on Chinese sites as ideal for 3d printing appear to have specs outside those listed on reprap site. And, I’m not sure that the specs given by manufacturer are entirely relevant without other info. Manufacturer (JKM) says it’s a 2-phase “hybrid” motor that runs at 1.7 A (current/phase). Looking at reprap website, they suggest 1.5 - 1.8 A/phase (3-8 mH) inductance at 1-4 volts. One motor they list as insufficient has 0.33A current/phase, 46 mH inductance at a rated voltage of 12v. I’m thinking that this motor may have been rated at 1.7 A/phase at very high voltage as voltage and inductance were not given in the specs. This may show how oblivious I am, if it turns out that my observations are irrelevant, but I’m thinking that the 1.7 A current rating may still be insufficient without listed voltage rating and/or inductance. Am I way off base, or just a little?
@donkjr I’m not saying build your own just that the drive near the top will run it. But they are low quality and will fail in the near future.