[infinity2022]

Hello all and thanks the community for sharing knowledge.
My questions are very simple and i think that they will be usefull for many others:
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How to check a cnc spindle using a multimeter.

I ve read in this forum that we check the resistance between pins 1 and 2, pins 2 and 3 and pins 1 and 3. (pin 4 is the ground which is not attached to the body of the spindle and we have to ground it in most of the cheap chinese spindles).
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If the above is correct, then

1. what is the acceptable resistance values between the pins ?

2. What if there is no resistance value (meaning no continuity)between 2 pins ?

3. What if 2 pins are shorted ? (redistance= 0 ohms)

4. Can a damaged spindle, catastrophically damage an inverter and how can this happen ?

5. How can we avoid the damage of the inverter caused be a damaged spindle?

Please answer only if you know well. The aim of this thread is also to help others. Please try to keep the thread clean - no flame between members. Thanks in advance.

[mactec54]

Hello all and thanks the community for sharing knowledge.
My questions are very simple and i think that they will be usefull for many others:
-------
How to check a cnc spindle using a multimeter.

I ve read in this forum that we check the resistance between pins 1 and 2, pins 2 and 3 and pins 1 and 3. (pin 4 is the ground which is not attached to the body of the spindle and we have to ground it in most of the cheap chinese spindles).
-----
If the above is correct, then

1. what is the acceptable resistance values between the pins?

This depends on the manufacture this number can vary depending on how much wire is used, as long as all (3) main pin checks are all very close to the same and no test to Ground then the spindle is normally Ok, this is only a rough test, and if done correctly this will tell you whether the Spindle is good or bad, or need further tests

2. What if there is no resistance value (meaning no continuity) between 2 pins?

There is a winding that has a break, or it is being tested incorrectly.

3. What if 2 pins are shorted? (resistance= 0 ohms)

Check the Plug Wiring, or method of testing, this normally means that the windings are shorted / cooked.

4. Can a damaged spindle, catastrophically damage an inverter and how can this happen?

Because of the high energy created when a spindle is cooked this energy feeds back to the VFD Drive and fries the IGBTs quite often this was caused by the VFD Drive having incorrect Parameters set or trying to run these HSS spindles too slow

5. How can we avoid the damage of the inverter caused be a damaged spindle?

It just depends on how robust the VFD Drive is and what protection it has to cope with a dead short, expensive VFD Drives do have some protection, they still can fail if VFD Drive Parameters are set incorrect for the spindle being used, there is very little that can protect electronics from a dead short

If any of this this happens to a Spindle, it normally means that the VFD Drive has not been setup correctly, meaning incorrect wiring or Parameters have not been set correct, it is rare that a spindle is damaged by normal use

Things that can damage these High-Speed Spindles

(1) Wiring

(2) Parameters incorrectly set

(3) Stalling

(4) Over Heating

(5) Trying to cut materials that the Spindle was not designed to do

[infinity2022]

mactec54, thanks for your time. your reply will be very helpful for me and i think for others as well !