[15mgtar]

no the water always runs cool and it flows much2 faster because I am using bigger hose and also a waterjet pump 250Watt with a pressure tank. when I touch the middle part of the spindle it is always and never ever get warm. but on the bottom where there are 2 bearings it is really2 hot!!!. please help guys I'm sooo frustrated I already spend $400 on parts. btw do I need to grease the brand new NSK 7005c bearing? please give me an answer.

[yngndrw]

I'm afraid I can't help you with the grease question, but is the cooling jacket blocked at the top from poor machining ? I.e. So it's only cooling the top ?

Also could dust / dirt have gotten into the bearings ? I'd personally advise that you find the cause to the problem before fixing the bearings, otherwise you may find that you'll end up with more broken bearings.

[15mgtar]

no I don't think so because the first 2 days running continously wasn't a problem at all. The bottom part is cool the same as the top! and the water flowing the same rate at all time. Funny think after 2 days of use the bearing sounds so much different and gets very hot. I use the same tool as I did from the first 2 days. It is 12mm solid carbide endmill. I still need the grease answer though. I don't want to smoke another $70.

[diyengineer]

http://www.mcguirebearing.com/

call them and ask if that bearing should be greased and with what. Normal bearing grease probably wont cut it since its such high rpm.

[jsheerin]

How is your cutter entering the material? Is it plunging straight down or are you ramping it into the material, and at what angle? Other spindle manufacturers typically recommend a small ramp angle (20 degrees or less) to prevent damage to the bearings. You don't want to drill straight down with these. See:
http://www.pdscolombo.com/pdf/PDS%20...0Care%2007.pdf

[chimpera]

I read that some spindles have 4 bearings and are therefor better for plunging and aluminum. Can anyone tell me which ones those are?
Thanks, Ben

[chimpera]

from my research i have found some units have 2 bearing other 3 bearing
and other 4 bearings... inquire do you home work... if your doing aluminum
work you want 4 bearings 2 per side. also some use nsk other fag bearings
and some no names...

Can you tell me which ones have 3-4?
Thanks, Ben

[15mgtar]

plunging straight at 1000mm/min at dept of 6mm how much RPM should i use if i am using 12mm flat endmill with teakwood as stocks?
I am tried of this chinese spindle maybe it is too small for a big cut taking aout 8 hours or more. I am looking for 5.5kw~7.5KW spindle
I think that will do the job nicely. is pdscolombo price competitive?
btw may spindle have only 2 7005c beariings and 1 small one at the top.
I grease the nsk 7005c with a special grease pack em really good and it gets hot around 95C I am not sure if this is normal.

[rowbare]

Kluber Isoflex NBU 15 seems to be one of the better greases for spindle bearings:
http://www.klueber.com/

See http://www.cnccookbook.com/CCBlogMay2010.htm look for the post on 4/27/10
"Kluber's Magic Spindle Bearing Grease"

bob

[15mgtar]

I have a new problem with my 2.2kw water cool Chai's spindle the torque drops drastically when I'm cutting 5mm deep teakwood using 10mm flat endmills. What seems to be the cause? I'm using a new Hitachi inverter and also the 2.2kw unit is only 2 weeks old. It was running fine before.

[yngndrw]

Could it just be a blunt cutter ?

[15mgtar]

nope, the endmill is brand new. I am not sure which one is faulty could it be the hitachi? or the spindle?

[yngndrw]

I'd advise that you check the cable between the VFD and the spindle - Check that the connections are well made and not lose or anything.

Then check the settings in the VFD to make sure it's not limiting the current or anything, you could even reset all of the settings and go through them all again.

Finally you should disconnect the spindle and check the resistance of each winding. The resistances should all be approximately the same.

[15mgtar]

the spec of the spindle 2.2kw water cool is: 2.2Kw 220V 8A 400Hz number of pole(I don't know). I check the resistance of the spindle motor U to V = 1.7 ohm U to W= 1.7ohm V to W = 1.7 ohm U,V,W to ground is 0 ohm. I check the cable they are OK. but How do I check the Hitach X200???? the problem is that when the spindle is running and I apply load the torque drops drastically. please help guys I'm going to nuts this is my 2nd 2 weeks old spindle motor from Chai and the Hitachi x200 is about 2 months old.

[yngndrw]

I believe the number of poles of this kind of motor is 2 so you should try setting that, though I think VFDs only use that information for the RPM output.

Also from memory I think my 1.5KW spindle had 8A printed on the side of it so you might want to double check that yours should be that as it seems a bit load.

Here's the manual for your VFD if you don't already have it:
http://www.gebhardt.se/upload/dok/pd...nstruction.pdf

You should monitor the current reading on the VFD while the spindle's under full load to make sure that it isn't being limited by the inverter for whatever reason. (D002)

You should also monitor the output voltage (D013) and the temperature of the VFD under load. (D018)

The base frequency should be 100Hz (A003) (I'm also assuming the minimum 6,000RPM limit that is used for the air cooled motors, just in case.) and the maximum frequency should be 400Hz. (A004) If you don't set the base frequency to that, you won't have full torque throughout the speed range. (6,000RPM -> 24,000RPM)

The VFD does have a torque boost option, but I believe this is only for speed which are below the base frequency.

You can set the frequency upper (A061) and lower (A062) limits to 400Hz and 100Hz as well to ensure the motor stays within its safe range.

You should also check the temperature of the motor under load as the VFD has thermal overload prevention of both the VFD and the motor - It uses the winding characteristics to measure the motors temperature. This may be linked to the bearing problems you were also having if the motors are overheating. If the VFD detects overheating, it may reduce the torque to cool it.

Hope that helps you find your problems.

[diyengineer]

If you wanted to go lower then 6,000 and the problem is because it possibly will overheat. I would rip that fan out of there and install a 200CFM+ highspeed 12V fan (92mm-120mm) above it with a custom air funnel.

I believe the number of poles of this kind of motor is 2 so you should try setting that, though I think VFDs only use that information for the RPM output.

Also from memory I think my 1.5KW spindle had 8A printed on the side of it so you might want to double check that yours should be that as it seems a bit load.

Here's the manual for your VFD if you don't already have it:
http://www.gebhardt.se/upload/dok/pd...nstruction.pdf

You should monitor the current reading on the VFD while the spindle's under full load to make sure that it isn't being limited by the inverter for whatever reason. (D002)

You should also monitor the output voltage (D013) and the temperature of the VFD under load. (D018)

The base frequency should be 100Hz (A003) (I'm also assuming the minimum 6,000RPM limit that is used for the air cooled motors, just in case.) and the maximum frequency should be 400Hz. (A004) If you don't set the base frequency to that, you won't have full torque throughout the speed range. (6,000RPM -> 24,000RPM)

The VFD does have a torque boost option, but I believe this is only for speed which are below the base frequency.

You can set the frequency upper (A061) and lower (A062) limits to 400Hz and 100Hz as well to ensure the motor stays within its safe range.

You should also check the temperature of the motor under load as the VFD has thermal overload prevention of both the VFD and the motor - It uses the winding characteristics to measure the motors temperature. This may be linked to the bearing problems you were also having if the motors are overheating. If the VFD detects overheating, it may reduce the torque to cool it.

Hope that helps you find your problems.

[15mgtar]

my spindle is 2.2kw watercooled guys

[yngndrw]

Well you can skip some of the lower speed limit stuff then but I'd suggest that you still measure the spindle's temperature just in case.

[15mgtar]

the spindle runs cool but even without load the spindle speed is not constant

[yngndrw]

Does it still turn freely by hand ?

It sounds to me as if the VFD is at fault, the VFD controls the speed via the frequency.