Spindle not running - Need Help

[Doddy]

I'm assuming that those are the readings from the 3-pin connector, with the other end connected to the spindle. And that those are in the milli-Ohm range?

I'm asking because I've just been to measure my 2.2kW spindle...



All combinations between three pins were measured at 1.6 Ohm. (or, broadly speaking, 1600 milli Ohm) as...





A number of 1825, 1780 or 1755 would make sense, if on a milli-Ohm range (very unusual / expensive meter) - or possible presented as "1.825" Ohm?,

A value of 1825 Ohm would concern me somewhat.

[Lumiyo Ben]

I'm assuming that those are the readings from the 3-pin connector, with the other end connected to the spindle. And that those are in the milli-Ohm range?

I'm asking because I've just been to measure my 2.2kW spindle...



All combinations between three pins were measured at 1.6 Ohm. (or, broadly speaking, 1600 milli Ohm) as...





A number of 1825, 1780 or 1755 would make sense, if on a milli-Ohm range (very unusual / expensive meter) - or possible presented as "1.825" Ohm?,

A value of 1825 Ohm would concern me somewhat.

I’ve double checked the readings and they are showing the same. The metre is showing its reading at milli-Ohm

[Doddy]

Ah, good... I did want to confirm that - it's unusual (or maybe I'm behind the times) to get general purpose DMMs with milli-Ohm ranges. Never mind, onwards and upwards.

I'm assuming that you're confident then that the three phases of the motor are all in the same region of around 1.6-1.8 Ohm then that's largely convinced me that the spindle is okay - and that's no surprise, there's not usually problems with the spindle I would always check the harness (cables fracture over time if moved) - but I think you've discounted that. The weak link in the chain would always be the power electronics on the VFD.

If you had a working system (ironic, I know) I'd recommend reconfiguring the VFD to drive it manually from the VFD just to remove every other variable from the equation, but not being able to test the spindle means this is likely to just add confusion to the situation. I'm depending on your description that you've been able to present demands from Mach to the VFD (creating the rotational demands - the 'F400.0'/'F090.0' etc previously, and the indication of a forward command ('FOR' LED on the first picture... though you've not re-confirmed that in a later question).

At this point I personally would be measuring the 3-phase outputs from the VFD to the spindle, with a rotational demand of "F050.0" (M3 S300, I think we got to). But, this is something you should only attempt if you know what you're doing. My thoughts are, though, that you're likely to see basically no volts on the 3-phase output, then I'd be into the VFD to check the internal DC bus on the power board. But, unless you're confident with what you're doing I cannot recommend that you try this - it's potentially hazardous. Are you confident working on powered mains supplies?

[Lumiyo Ben]

Ah, good... I did want to confirm that - it's unusual (or maybe I'm behind the times) to get general purpose DMMs with milli-Ohm ranges. Never mind, onwards and upwards.

I'm assuming that you're confident then that the three phases of the motor are all in the same region of around 1.6-1.8 Ohm then that's largely convinced me that the spindle is okay - and that's no surprise, there's not usually problems with the spindle I would always check the harness (cables fracture over time if moved) - but I think you've discounted that. The weak link in the chain would always be the power electronics on the VFD.

If you had a working system (ironic, I know) I'd recommend reconfiguring the VFD to drive it manually from the VFD just to remove every other variable from the equation, but not being able to test the spindle means this is likely to just add confusion to the situation. I'm depending on your description that you've been able to present demands from Mach to the VFD (creating the rotational demands - the 'F400.0'/'F090.0' etc previously, and the indication of a forward command ('FOR' LED on the first picture... though you've not re-confirmed that in a later question).

At this point I personally would be measuring the 3-phase outputs from the VFD to the spindle, with a rotational demand of "F050.0" (M3 S300, I think we got to). But, this is something you should only attempt if you know what you're doing. My thoughts are, though, that you're likely to see basically no volts on the 3-phase output, then I'd be into the VFD to check the internal DC bus on the power board. But, unless you're confident with what you're doing I cannot recommend that you try this - it's potentially hazardous. Are you confident working on powered mains supplies?

I’m really not confident doing this test. But thank you so much for your help.

Cheers
Ben