Wiring diagram advice

[Happy Feet]

If you ran a 24000rpm spindle lower than 6Krpm, then it is most likely cooked, the inductive reactance of these motors is very low once you go below this rpm, and the current goes up proportionately..

so you are saying i need a new vfd and spindle too....? is there any way to check the damage on the spindle ? i ran this lower than 1000 rpm several times for testing.

edit: when the incident happened the estop was pressed so the spindle had no moves

[Al_The_Man]

If you can power up the VFD without the motor connected and go through some of the functions of setting parameters without an alarm etc it should be OK.
Al.

[mactec54]

good day folks.

Yesterday morning i got a very unpleasent suprice. i switched on the cnc got away for 2 minutes and when i got back there was that smell and of course some smoke...!

i dont know the cause of this . the only thing i notice was the fan wasn't spin and it was hot and melted...! i opened the vfd and took this picture.



the spindle is worked as it should some minutes after the smoke here is a



. i have noticed i had my minimum frequency to 0 instead of 120 and and the night before that the spindle had a drop on rpms every few seconds and the steppers were acting strange too ( talked to me @ openbuild about a pulse train jitter).

The bad thing is that i also didn't get my cable to the ground from spindle connected and i dont know what else i ve done wrong.

Is this thing repairable on topic market guys or do i have to go for a new one. i have runned the vfd with the spindle for a while with two 12v fans in series and it seems it working but i think it is a matter of time.

if you have any idea what could be the cause please let me know.

That looks like the low voltage Board, how did you have the input terminals connected and to what

Having the minimum setting at 0 did not smoke that board, not have a Ground at the spindle can do this, or incorrect terminal wiring

You can check the spindle with a meter, all 3 pins should have almost the same readings

Pin 1 to Pin 2
Pin 2 to Pin 3
Pin3 to Pin 1

Ground Pin 4 to spindle body

[Happy Feet]

sorry guys i was out of order these days.

I have run the cnc for about 5 minutes twice and all seems fine. today i got my rs485 boards ( one db9 and one usb) .

i ll check the spindle's resistance today and will post the readings here.

my guess is that something happened with the fan for the very beginning and that probably caused an overtemp issue.

[Happy Feet]

ok the resistance beetween the 3 pins were identical 4.4ohm . the 4th pin doesnt short with the spindle body . my earth connection is connected to the body through the water outlets.

i also installed the usb board for the vfd and the software it needs ( ms packages, netframework and dll) . i am keep getting that the spindle is unable to communicate with mach3.

i ll go doublecheck everything.

edit: it wasnt hard to find . i had the data+ and data- wrong way. now it everything ok . something that i have noticed . My spindle doen't go more than 0.7 amps no matter the speed it is running. is it normal ? also what can i do to get the amps on mach? i am only getting the rpm at dro.

[ericks]

ok the resistance beetween the 3 pins were identical 4.4ohm . the 4th pin doesnt short with the spindle body . my earth connection is connected to the body through the water outlets.


i ll go doublecheck everything.

edit: it wasnt hard to find . i had the data+ and data- wrong way. now it everything ok . something that i have noticed . My spindle doen't go more than 0.7 amps no matter the speed it is running. is it normal ? also what can i do to get the amps on mach? i am only getting the rpm at dro.

Having a "balanced" resistance between your spindle windings is what you want, so you good there.
You also have to now measure between any one of the three pins and the spindle body......this will indicate insulation resistance to earth. Ideally with a multimeter you want an open circuit.
I use an insulation tester for this test but you should get an idea with your multimeter.

note you want to do this test with the spindle motor disconnected from the VFD, otherwise you may get false readings

[ericks]

A few things to consider with regards to the VFD cabling etc...

1) The cable used between the VFD and spindle motor should be rated correctly......that is current carrying capacity and the cable insulation should be able to withstand the voltage applied, else there would be "leakage"
2) When testing for a fault on the spindle motor.....don't forget you could have a short or break in the wiring to the spindle. So its easier to start the test by testing from the cable at the VFD.....this way you actually testing the cable too. If you find a fault then you would disconnect/unplug the cable from the spindle motor to determine whether its the motor or cable that's faulty