Spindle RPM not correct

Printable View

08-14-2021, 01:10 AM
Borneoben

Spindle RPM not correct

Hi Guys
Finally got around to setting up the Spindle control with UCCNC - AXBB-E and my HY VFD.
Everything is working great apart from the RPM is not accurate.
When Sset calls for 12000 RPM the VFD is correct and shows 12000 RPM
When Sset calls for 16000 RPM the VFD only reach's about 14800 RPM just about 10% difference
When Sset calls for 1800 rpm the VFD only reads 16500 RPM
When Sset calls for 24000 RPM VFD only shows 20000 RPM
The error gets bigger the higher the RPM
What settings do I need to adjust to get the VFD to reach the correct RPM?

Cheers
08-14-2021, 05:56 PM
mactec54

Re: Spindle RPM not correct

Quote:

Originally Posted by Borneoben

[FONT="]Hi Guys
Finally got around to setting up the Spindle control with UCCNC - AXBB-E and my HY VFD.
Everything is working great apart from the RPM is not accurate.
When Sset calls for 12000 RPM the VFD is correct and shows 12000 RPM
When Sset calls for 16000 RPM the VFD only reach's about 14800 RPM just about 10% difference
When Sset calls for 1800 rpm the VFD only reads 16500 RPM
When Sset calls for 24000 RPM VFD only shows 20000 RPM
The error gets bigger the higher the RPM
What settings do I need to adjust to get the VFD to reach the correct RPM?

[/FONT]
Cheers

Have you checked the voltage output at those speeds @ 12000 it should be around 5v

Have you set the Spindle Velocity Minimum and Maximin 6000 and 24000 for water cooled spindle in the UCCNC software
08-14-2021, 06:21 PM
A_Camera

Re: Spindle RPM not correct

Quote:

Originally Posted by Borneoben

Hi Guys
Finally got around to setting up the Spindle control with UCCNC - AXBB-E and my HY VFD.
Everything is working great apart from the RPM is not accurate.
When Sset calls for 12000 RPM the VFD is correct and shows 12000 RPM
When Sset calls for 16000 RPM the VFD only reach's about 14800 RPM just about 10% difference
When Sset calls for 1800 rpm the VFD only reads 16500 RPM
When Sset calls for 24000 RPM VFD only shows 20000 RPM
The error gets bigger the higher the RPM
What settings do I need to adjust to get the VFD to reach the correct RPM?

Cheers

Where does the RPM reading comes from? Is it from an external meter, or from the VFD? It sounds like you have a very bad and poor quality D/A converter. Perhaps the AXBBE is faulty, or it is incorrectly configured. Measure the RPM, and the D/A output voltage to check which is right and which is wrong. Perhaps the VFD is the problem. Difficult to say with so little facts about what is measured where.