Amazon Chinese Grinder Issues

tomang07

tomang07

Active Member
Outside of the obvious...

My cheap Chinesium grinder is unsurprisingly on the fritz. It will run great until I put any remotely substantial pressure on it, (for 5 seconds or more) and then it will just power off for a minute or so.

It seems like it's overheating or drawing too much power. It runs off 110 through an Asian 110/220 converter box and then the VFD for speed control

It's 1.5 or 2hp motor, no markings on it so no way to know for sure.

I have taken the power supply and VFD apart and neither were dirty or clogged up.

At this point I'm trying to figure out how to f this pig. New power supply or VFD is about $100 each.

My thought is to buy a good KB 27/29 and use that instead, but not really knowing anything about the motor makes that a bit of a gamble.

Any experience with this would be appreciated. A new grinder is not in the cards at the moment.

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Do you have your grinder on any kind of power strip? I had this problem when I first setup my grinder and the power strip kept resetting. If that's not the case I would suspect your converter box.

I'd wait and see what more experienced users here might have to say. In spite of my computer background, electronics really isn't my forte.
 
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Until you know what type of motor you've got there is no way to tell what you need. Do you have a link to the Amazon grinder?

What part of the world are you located in? Type of power used?
 
I'm in the US, so 60hz 110/220v power. It's plugged directly into the wall in 10/2 wiring on a 20amp circuit.

I'm thinking of hooking the VFD directly to 220v and bypassing the power supply. The manual isn't great and I'm no wiz when it comes to electrical.

No, I have no way to find out exactly what the motor is, there's no markings or tags on it. 20210610_072725.jpg20210610_072255.jpg20210611_065140.jpg20210610_072301.jpg

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Does your VFD display give any kind of fault code?

It's possible that you need to adjust some parameters on the drive. Do you have the manual?
 
Still just throwing stuff out to try and help. Are you by chance using a GFIC outlet? Those and VFD’s do not get along very well.
 
OK, I think we've got what's needed now - not sure at all what the power supply is all about, but it looks like you've got a typical Chinese VFD that takes 1 ph input, but it's a tad confusing what the input power is. One tag shows 120 or 220 input while the other shows 220 vac 1 ph input. It does look like the motor is wired for 220 vac 3 ph which is what you want.

There is a decent chance the VFD is wired for 1 ph 220 vac input and the power supply is 120 vac input and 220 vac output. Most all the Chinese VFDs require 220 input. Also, as Chris mentioned sometimes those GFIC recepts don't play nice with VFDs. Also the Arc Fault Circuit Interrupters (AFCI) breakers can give problems. First step would be to confirm you're not plugged into either a GFIC or AFCU breaker.

If not, next step would be to confirm the voltage on the input and output of the power supply. If you've got 220 vac available I suspect the power supply isn't needed at all.
 
I checked the output on the converter, it was 220, so I bought a plug and hooked it up directly to 220, as it shows in the manual, now it's even worse, like it's getting a stutter and won't ramp up at all.

There is absolutely NO MARKINGS WHATSOEVER on the motor. Took the covers off and looked all over, nada.

20210612_112646.jpg20210612_112802(0).jpg20210612_112903.jpg

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I'm really starting to hate this thing.


Disregard the mess.... sorry.... lol

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Sometimes I'm thick and miss important details, so forgive me if my questions are redundant to info you've already given.

1) What is the voltage, rpm, HP, and phase as you understand it to be when you purchased it?

2) What voltage and phase input is your transformer? Do you need a transformer if your if your VFD input is the same as your regular power supply?

3) What voltage and phase input and output is your VFD?
 
tkroenlein said:
Sometimes I'm thick and miss important details, so forgive me if my questions are redundant to info you've already given.

1) What is the voltage, rpm, HP, and phase as you understand it to be when you purchased it?

2) What voltage and phase input is your transformer? Do you need a transformer if your if your VFD input is the same as your regular power supply?

3) What voltage and phase input and output is your VFD?
Click to expand...

1) I don't know. It was years ago and has no information on it. It was supposed to be 1.5 or 2hp. Motor is 3 phase.

2) Transformer is 110 input to 220 single phase output.

3) VFD converts the 220 single phase to 3 phase, which is how it does the speed control. It came with the transformer, so that's how I was running it. I only today hooked it directly up to 220 bypassing the transformer, and now it's doing what I showed in the video.

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Interesting the sound and movement in the video - Do I understand the grinder ran just fine for several years? Just recently when on blink? If so, I'd suspect the VFD drive itself. Perhaps some parameters got scrambled with an electrical spike or something? OR - just scrambled brain? I might consider spending $75 shipped for a new VFD for the grinder: https://www.ebay.com/itm/263200037164

There are several VFDs on market for <$100, unless you want a NEMA 4 and that's expensive
 
Like Ken asked was it running okay before. When I set up my grinder I had something wired wrong and it made a knocking sound like yours. I know it's not helpful. Maybe you could test the motor.
 
It worked fine initially, but it started gradually, occasionally shutting off, and doing it more and more frequently. Now If I grind for more than 5 seconds it shuts off. It will run forever, until I start to grind, then it shuts off like someone turned the power off.

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tomang07 said:
1) I don't know. It was years ago and has no information on it. It was supposed to be 1.5 or 2hp. Motor is 3 phase.

2) Transformer is 110 input to 220 single phase output.

3) VFD converts the 220 single phase to 3 phase, which is how it does the speed control. It came with the transformer, so that's how I was running it. I only today hooked it directly up to 220 bypassing the transformer, and now it's doing what I showed in the video.

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Click to expand...
Ok. I've re-read the thread and watched the vid again. I understand now that you've ran this for some time and this is a new issue.
You're either losing a phase from the VFD or have a bad winding. That shudder means certain death of one of your components. The video Gilbert posted is excellent, and ohming out the windings will tell you which one it is.
 
Well, now I suspect it is the VFD, I re- hooked up the transformer and it's now doing the exact same thing with the transformer.

Guess a new VFD is in my future, too.

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