Thank you for your input. You bring up some interesting points. I’ve spent the last few several hours reading online trying to get to the bottom of everything you’ve mentioned.
As an aside, we are now talking on a different subject. I assume you have no objectionable things to say about running a 380V motor off of 220V so long as the current input is limited to the same as it would be at 380V? Effectively derating the motor along a portion of it’s speed range? Start up current aside. I’m wondering about efficiency and if there are any meaningful physical differences in the windings and components between a motor that is designed and manufactured to run at 220V along the blue line in my graph and a 380 designed for the pink line in my graph that would make this a bad idea?
A VFD can shield your 50A breaker from motor starting load by ramping.
Excellent! It’s a 60A breaker. I just wasn’t planning to push it over 50A.
- A VFD's capacitor bank is on the uncontrolled side of the VFD. It presents an inrush load of its own. That load is greater when the VFD has had to be upsized to also operate off single-phase input.
The user guides for Delta-A and ABB VFDs I looked at don’t even mention inrush current. The Delta-B mentions it and refers to Appendix B, accessories, for the use of an AC Input Reactor. Of course, I don’t know if the inrush they are referring to is for the capacitors or the VFD output (compressor with a short ramp up time?). The Yaskawa A1000 series user guide mentions fault codes and such for their inrush prevention circuit, which I assume is for the VFD’s capacitor bank as you mentioned. It’s interesting to note that they don’t see it as a special enough feature to mention it on the Specifications & Features page for the A1000 series.
I found this quote somewhere. I’m afraid if I post a link I may be banned
. I don’t seem to have good luck posting links or pictures.
“VFDs have a capacitor charging inrush current that occur only when power is first applied to the VFD. All VFDs must limit that inrush to prevent damage to the diodes and DC bus capacitors. Various methods including combinations of methods are used to limit the charging current. VFDs are normally not energized and de-energized very often and the motor is normally prevented from starting until capacitor charging is complete. The peak charging current is very brief and the magnitude is partly determined by the source impedance. It is rarely a concern for the user and VFD manufacturers don't usually publish information about it. AC and/or DC inductance that is often built into VFDs to limit harmonic current also helps to limit charging current.”
So I guess it depends on the VFD. Something to think about for sure so thanks for bringing it up.
I’ve seen several posts from people on this forum who have oversized a VFD so that it can do the phase conversion for them. I’d really like to hear from someone who has done it. Can anyone please measure the current in Amps of their single phase input when power is applied to their VFD and compare that to the Input Current on the nameplate please? I’ve found lots of information in my searches from people explaining how to do the metrology, but no actual measurements. Does anyone know of any similar measurements that have already been posted online
Every player in the room is straining, and to get to starvation rations, even if made to work.
I disagree. If the 60A can handle the capacitors in the VFD when it is powered up (a momentary condition), I will have a nice ISO30 ATC spindle that I can run from home at up to 6.37 KW, which I won’t ever use. That Sir, is not starving. It just depends on the start up.
What I do want to take advantage of is the higher power available at lower RPMs that I would get with this spindle. So derating it in the higher RPM range is nothing I even care about so long as there are no ill effects. I’m concerned about what the efficiency will be.
So I ask.. just how hard is it to get the paltry 60A service upgraded to 100A or 200A?
I don’t know. I can look into it.
Might it be better to trade-down to a less thirsty machine-tool?
Yes. I actually have it up for trade. Some joker offered me $250 CAD for it. Still looking.
I was also looking at a 5.5kW ATC spindle that is available to me at a reasonable price. But the power curve was constant v/f all the way up to 18000 RPM, which would give me less HP than I want at lower RPMs, plus it was rated at 22 Amps, not much different a scenario that what I get by dropping the voltage on the one I already have. I still haven’t decided.
HSD makes some nice lower powered spindles with ATC that would suit my needs. They cost money that I don’t have. Have you looked at the Canadian dollar lately? Even Chinese knock offs with ATC cost over 3 grand US. LOL. If you know someone who wants to trade, please let me know, until then this thread is simply about whether or not I can use the very nice spindle I have at 220V effectively.
As always, thank you for your input!