I can’t help notice that all the power supplies only have two ports for AC power. Is there no ground? Is that safe?
In AC, the two reasons to have a ground pin are:
- To give a reference voltage for DC electronics. The spindle doesn’t need that.
- To ground a metal case. Imagine the positive AC wire comes loose somewhere in my fridge, and leans against the case. If it is grounded it will get angry and then blow the fuse. If it isn’t grounded I might short it to ground when I open it in the morning.
My vacuum cleaner doesn’t have a ground. It is just a motor and it is a plastic case. It’s completely safe. Neither do some brand name power tools.
It is true that if a device is double insulated then it does not need an earth for safety, however many of these Chinese spindles have an outside metal case…so to satisfy most countries import regulations (I assume you are in America) the double insulation must be internal to the device such that any broken wire internally cannot touch the outer casing. Chinese consumers, or at least Chinese manufacturers are not generally that fussy. Check for your countries import sticker, if it has one then it must satisfy your countries import safety requirements…if it doesn’t have the sticker…ummmmm!
My Chinese hand trimmer doesn’t have an earth connection either and the lower part of it appears to be aluminium, it has what appears to be a CE sticker on it (Certificate European I’m in Europe) but it could be a chinese ce (china export) sticker…now tell me how the Chinese just happened to invent a export sticker that looks just like the copyrighted CE European sticker 
There should be a ground. If I look at the wiring of this one for example, the 4th pin is ground.
https://www.aliexpress.com/snapshot/0.html?orderId=8016408715160589
The CE stickers are often meaningless with cheap Chinese products. They use stickers which have a different spacing or slightly different font sometimes, so they aren’t really certified.
This is what confuses me. The spindles have a ground connection, but the power supplies don’t
Depends on the VFD, I guess. Imo they all have a ground terminal. Here for example, look at page 14
I haven’t received my spindle and VFD yet - it will still take a couple weeks.
Your link gives https://www.aliexpress.com/pageNotFound
I guess we are talking spindles and spindles here. There are single phase, single speed spindles that do not have an earth, I have one in front of me, the power cable has two conductors, one brown and the other an interesting blue/green stripe! intended to by plugged straight into the mains. I metered it out just to be sure the blue/green conductor wasn’t connected to the aluminium body!
Then you have proper grown up spindles…usually 3 phase and speed controllable…Daniel, what type of power supply are you thinking of with no earth terminal?
Gotta love Amazon links
You can cut everything after the question mark.
Doesn’t need the /ref= either.
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necro for psa purposes…
My Huanyang Chinese spindle was not grounded, despite earth being connected to the ground pin. The pin has no internal connection apparently. I read on other forums this is common with these things.
So for safety when using these spindles, you should measure ohms between the ground pin and the metal case of the spindle with a multimeter. If it is open loop (likely), you should modify it accordingly.
This can be done by disassembling the top, adding a screw terminal inside and soldering a wire to the 4pin connector (difficult).
Alternatively, just remove one of the top bolts and sand a spot above the hole to bare metal. Then connect an earth wire to a loop terminal, and tighten it on the bare metal with the original bolt. Verify continuity with a meter before use.
Most of the Chinese vfds also don’t have a second ground terminal to match. Stacking spade terminals is an easy way to use one earth screw terminal for the mains and the spindle.