@George_Allen , there is no ‘red & black’, which was my point.
@Mike_Thornbury ok. I’m going to bed.
Running 240VAC equipment using 2 phases of a 3 phase 120V power grid?
a) Are the phases guaranteed to be 120° apart? (I’m not so sure about the quality of the US power grid.)
b) What do you do in case of a power outage? Not all phases fail or come back at the same time.
@Marcus_Wolschon I don’t think he has a 3-phase service. Did not hear anyone describe that. (Nor have I actually heard of a 3-phase 120V service.)
@Mike_Thornbury
Regarding this comment: >>I’m not sure about +Jay Polo’s wiring as the colours are wrong - white (in such an implementation) is neutral - you should have black to R and red to T, if you were using conventional wiring, and no neutral.
Sure, if would be nice if my power cord came with Black, Red, and Green, instead of Black White, and Green. But it is wired properly. There is no difference at all between the R and T terminals. You can place either of the 240VAC Hot wires on either of these terminals.
I’ll also mention, that my primary concern over a knock-off VFD would be the reliability of the power components. The way these devices work is they first rectify the incoming power into a DC voltage bus. Then they use transistors to pulse that power out to the spindle at the desired voltage and frequency. Lots of high power components and switching happening inside there, meaning things that can easily burn out if corners are cut.
@Jay_Polo I think you were right about the knock off vfd. I haven’t seen any comparable model with my model number. I decided to purchase a 220v 2.2 KW VFD through Amazon from the manufacturer. At least I can justify the purchase because the other VFD was not the same capacity as my spindle. It cost a little more than the other, but this is directly through the company. I don’t think I can get my $$ back on the other because it has been a year since I purchased it.
@Paul_Frederick I don’t know if you have been following this thread, but I would wonder what your thoughts were. I now believe, like Jay Polo, that I may have been slipped a “knock-off” VFD because the screw terminal layout is different from others that have the exact same model number. And, the terminals are not labeled except for 2 terminals that are labeled ground. If those 2 screw terminal labels are correct, then the outside sticker (which I thought was the actual label) is not accurate. Since I saw that, I decided to purchase a 220v 2.2 KW VFD through Amazon from the manufacturer. At least I can justify the purchase because now I have the proper capacity VFD (2.2 KW vs 1.5 KW). I’m thinking that I should be able to wire the VFD from the 4-wire outlet if the screw terminals are similar to other examples of Huangyang VFDs with a connection to R, S, T and to Ground.
@George_Allen You could be right. There’s a lot of counterfeiting of goods these days. Electronics is especially targeted too. That’s why when I buy I often buy counterfeit goods on purpose. Then I know I’m not getting ripped off.
@Paul_Frederick how would I go about finding out what the screw terminals actually are? The sticker on the front or the other grounding symbols inside? They contradict each other.
Have you seen the photos? It’s REAL confusing.
Combine that with the 4-wire - 3-wire issue and I’m about to drive myself crazy.
I might even send you the “knock-off” 220v 1.5 KW VFD, if you want it and can figure it out for all your help here, If I can get the new one I bought to work. It won’t be doing me any good.
@George_Allen George, it may have been a typo, but I want to make sure. This is not exactly correct: “…Huangyang VFDs with a connection to R, S, T and to Ground.”
To clarify, a 240 VAC power source is “single phase” (whether it is 3-wire or 4-wire). (You could in theory have a 3-phase 240 VAC supply but that is not common.) You should ask your maker space to confirm you are being provided a single-phase power source, to be sure.
Assuming single-phase 240VAC, there are two wiring configurations:
3-wire: Hot, Hot, Ground (What the HY VFD expects)
4-wire: Hot, Hot, Neutral, Ground (What the wall outlet will have)
Presuming single-phase 240 VAC (which is very likely) then regardless of whether your 240 VAC power source comes as either of the above configurations (3-wire or 4-wire) you will only connect 3 of those wires to an HY VFD.
Hot ==> R
Hot ==> T
Ground ==> Ground
Your Neutral wire does not have a connecting in the HY VFD. You will only use 2 of these 3 terminals: R, S, and T. (And technically either of the two Hot wires can connect to any of the R, S, or T screw terminals.)
Given you are being handed a 4-wire, you would first have all 4 of them connect to a terminal block. Then you would connect only the 3 wires that you need, directly to R, S, and GND on the VFD.
LMK if you have questions.
@Jay_Polo so, (assuming that the outlet is single phase) could I then connect to the terminal block, and then to a 2-pole RCD before running it to the VFD, or would I need a 3-pole RCD, or are you familiar with that? I initially bought the 2-pole RCD for the connection, but it’s looking like it should have been a 3-pole RCD.
@George_Allen I was not familiar with the term RCD until now. Essentially it is a GFCI. Depending on the design, there are a few things these can be used to protect against… 1.) a ground fault 2.) over current protection, and 3.) an arc fault.
Are you designing an electrical panel that this would protect? Or are you simply putting this in front of the VFD drive to protect it alone? It likely makes a difference in which you choose.
If it is just for the VFD, then note that you do not have a Neutral on your VFD, so your RCD would only have 2-poles, Hot and Hot, as they are the only two which carry current.
Now if you envision this RCD to be protecting a larger CNC electrical panel that powers several devices, (some being 120 VAC), then you will be using your Neutral and would want to make sure your RCD handles Hot-Hot-Neutral, which I presume would ‘count’ the Neutral and be called a 3-pole. Just make sure one of the poles is designed for the Neutral and that it is not a 3-phase device.
I cannot imagine an RCD would actually actively ‘switch’ the Ground open and closed (meaning have a pole for Ground.) It may well have a lug for Ground, but I doubt it would switch open if the circuit is tripped. Grounds are typically permanent connections.
LMK what you want to protect with it. If you find one that you are thinking of, share a link to it.
Not that I am being particularly cautious, but in my setup, I am running the 240VAC circuit for my VFD with only the over-current protection of the main circuit break in the panel closely sized for the power rating of the VFD. And I simply unplug the power cord when I want a physical disconnect. I’m comfortable with that.
@Jay_Polo I asked a friend (engineer) who said I could use it without one.
@George_Allen Great. I’m an EE who used to build industrial equipment 15+ years ago. Things don’t seem to have changed all that much over the years. Good luck!
@Jay_Polo Thanks.
@Jay_Polo jay, if you read my post straight after that one, I said the same thing 
it wasn’t a criticism
@George_Allen not to belabour the point, but why did you buy another 220v one, when they sell 110v units of the same spec? Now I’m confused