Mini-Lathe Electrical Issue

[devils4ever]

So, my Micro-Mark mini-lathe is giving me problems. When I push the green "on" button, I hear a kind of buzzing sound and the motor doesn't turn. The button doesn't seem to want to stay down. If I hold it, sometimes I can get the motor to turn on and run, but it's hit or miss.

I have it apart and I don't see any relays just power transistors and ICs.

Does anyone have any ideas?

 

[Eddyde]

Can you send any pictures? Back of switch, circuits, motor, info plates, etc.

 

[devils4ever]

Here's the main informational plate:


And here's the inside of the electronics enclosure:

 

[sdelivery]

Son of a gun it's almost like a mini vfd!
First is that circuit breaker tripped?
If so when does it trip?
Without a schematic , I would disconnect the power source and motor leads at the board.
Check minus bus with the black lead on the diode checking setting to the three other terminals (+ bus and power terminals)
Reverse your meter leads and run the same test again.
Do that at each of the bus and power terminals and write down your results as you go.
If the meter reading climbs ( shows a good capacitor) to O.L. write it down.
Post your results....

 

[devils4ever]

Here's the motor:

 

[devils4ever]

Here's the control panel on top:

 

[devils4ever]

There's no circuit breakers. Only a fuse on the control panel and a fuse on the main circuit board.

Yeah, it's more complicated than one would expect. There are 2 large cables going to the motor. The one has 4 large gauge wires (one is a ground). The other large cable has many, smaller gauge wires. I'm guessing it has a rotary encoded on it to monitor the speed. Also, I don't see any brushes, so it must be a brushless DC motor? Do brushless DC motor get fed with 3 phases? Or, maybe it's not a DC motor?

 

[WobblyHand]

Where's the green ON button that you speak of? The button that is wonky? I don't see a picture of that.

Looks like a brushless DC, although it appears to have 3 windings. There seem to be 6 power transistors (or similar) to give + or - DC voltage to the wiring. Could be a 3 phase motor, though.

 

[markba633csi]

It's a brushless DC motor which is a 3-phase motor with a permanent magnet rotor.
I believe the red button is some type of latching magnetic switch- might be failing
Can you get a close up picture of the data on the side of it?
-Mark
I have the same question as Wobbly- is the power button next to the fault light? or somewhere else?
You might want to contact Pete at olduhfguy.com

 

[Jim F]

The power switch is under the e-stop cover.