# Thread: ohms in chinese spindle

1. hi there can anyone tell me what value(ohms) betwen the 3 phase on a 2.2 kw
chinese spindle?

2. Depends on the motor, but typically would be 6 - 8ohms between phases if star-wired (I think this is the norm) and 2 - 3ohms if delta wired, though I have seen reports of as low as 0.5 - 1ohms.

Why do you need to know?

3. Originally Posted by irving2008
Depends on the motor, but typically would be 6 - 8ohms between phases if star-wired (I think this is the norm) and 2 - 3ohms if delta wired, though I have seen reports of as low as 0.5 - 1ohms.

Why do you need to know?

beacause i have one and the inverter blow the igtb so i´ve decided to buy another inverter,
but i want to make sure that my spindle isnt burn..
i´ve measured it between the 3 pins and he has 2.1 ohms in each.
i´m from portugal and there isn´t much support on this area here...
thanks edgar

4. Originally Posted by edgas10
i´ve measured it between the 3 pins and he has 2.1 ohms in each.
What did you measure it with, just a standard multimeter I assume? Are you sure the meter was zeroed properly (touch the probes together and check it displays 0.0ohm), as when measuring such small resistances it makes a big difference.

Since all the coils are the same resistance that's promising since if one phase had broken clearly there would be a difference. Check the resistance from all 3 pins to the spindle body, i.e. earth.

I will measure my spindle, which is the same rating, in a couple of minutes and report...

5. ## The Following User Says Thank You to Jonathan For This Useful Post:

6. hi yes i´ve measure with a standart multimeter.
in resistance mode (200ohms) when touching probes it displays 00.6 ohms.
the resistance between the 3 pins and earth gives me nothing , the multimeter just shows 1.
measuring the phases it gives me between the 3 pins , 2.0ohms
just a question , what type of motor is this? brushless???
does it work with dc voltage or ac????

7. AC at 400Hz or so... you must make sure your Inverter settings are right. If the startup frequency is too low for example it will overheat the motor windings but the motor won't turn. It is unusual to fry the Inverter, normally they are well protected. Have a read of this thread it might help.
Last edited by irving2008; 08-07-2012 at 12:27 AM.

8. Originally Posted by irving2008
AC at 400Hz or so... you must make sure your Inverter settings are right. If the startup frequency is too low for example it will overheat the motor windings but the motor won't turn. It is unusual to fry the Inverter, normally they are well protected. Have a read of this thread it might help.
hi there, did you checked the resistance value??

9. Originally Posted by edgas10
when touching probes it displays 00.6 ohms.

measuring the phases it gives me between the 3 pins , 2.0ohms
just a question , what type of motor is this? brushless???
It's a 3-phase induction motor, so if you can find a 3-phase induction motor (they're very common) you could use that to test the VFD with the right settings.

Since measuring 0.6ohms when the leads are touching means the actual resistance is 2.0-0.6=1.4 ohms for each phase. I just measured mine and got 1.6ohms, so yours sounds about right. Between all the pins and earth the resistance should be extremely high, so since your meter went out of range that's good, although you can't be sure without testing at a higher voltage. Either way it looks like the spindle is fine...

As irving has said, the settings on the VFD are critical so make sure they are correct before trying again.

10. thanks ,i know that the settings are critical, i had mine for aboutt a year, and he has worked for 8 hours a day (no breaks).
so if it is an ac motor is it possible to test directly to the mains supply(220ac)?

11. Originally Posted by edgas10
thanks ,i know that the settings are critical, i had mine for aboutt a year, and he has worked for 8 hours a day (no breaks).
so if it is an ac motor is it possible to test directly to the mains supply(220ac)?
No, these spindles are designed for 400Hz VFD only, they will not run on a 50Hz supply

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