DC Spindle motor tripps off frequently

[gowthu]

In mazak ST60,DC Spindle motor of 45 Kw tripps off frequently in running.motor field voltage is found ok(63V).motor also rewinded recently.Drive is Mitusubhisi Diarol DL-SBZ Drive.Is reason is field weakening during running due to drive or motor problem.Please guide me to trouble shoot the cause.

[Al_The_Man]

Does the drive have diagnostic LED's? if so what is displayed?
Does it trip under load or no load? What speeds does it trip at?
Al.

[gowthu]

It trips under load and also in 120 rpm ,2oo rpm.Since the problem occured in night shift, i did't observed the led display.I found motor gets heated up.After cleaning the blower motor heat gets reduced.during the checking process,component declamped while spindle is rotating.there is light oil leakage in the clamping & declamping solenoid.Is it the cause for component declamping?please let me know the causes for component declamping while running.
Thank you for your reply.

[Al_The_Man]

Is this jig clamps or drawbar clamp? If jig clamps then you would have to find out if they are unclamping electrically or some mechanical malfunction, such as loss of hydraulic pressure due to solenoid leaking etc.
The ability to trouble shoot by electrical prints and ladder dignostic is an important tool to have.
If the clamping pressure logic is tied to spindle logic, then the spindle could stop due to clamp pressure loss etc. especially if the clamp pressure you refer to is the drawbar.
Al.

[gowthu]

I observed some oil leakage in clamping solenoid.If we set the pressure in 20 kg it reduces to 17 kg in 2 hrs in spindle idle condition.there is no alarm observed.SYstem is Fanuc 6T.Ladder view is not possible.Is any other way to found the cause?

Thanks

[Al_The_Man]

The Diarol DL-SBZ Drive has a few diagnostic LED's so if the drive stops and there is no LED lit then it is almost like you have lost the command signal, this can be tested at the analogue input.
As for the clamping problem, which may be related, if a Mazak 6T , I had assumed it was a milling centre not a lathe, is the clamp you refer to the chuck unclamps or the tool turret?
The 6T sometimes had discrete relay logic (no PLC) or third party PLC, so you need the schematic diagram of the machine to trouble shoot in depth.
Al.

[gowthu]

Spindle DC motor gets trips down even running in lower rpm.Field voltage oscillates while running.At idle Field Voltage is 63V and it oscillates between 3 V to 63V while runnning.Is this problem is related iwith motor or drive.Drive is Mitusubhsi DL-SBZ model.Under voltage led lits when motor trips.

[Al_The_Man]

It sounds like the problem is in the drive. Is your incomming supply OK?
Check the motor over, brushes etc, and do a resitance check of the field and check for loose connections etc.
The field voltage should be constant, some drives have what is called field weakening, the field voltage is reduced to attain high rpm, this only occurs after a certain high rpm.
Al.

[itmancnc]

You may want to try adjusting your field currents. The motor tag should provide your max. and min. currents.

[princeviju]

i have a problem in my spindle drive (diarol dl-sbz-2-7.5) no error leds are glowing but field voltage is ok and led 614 is not glowing in sb-sa pcb and no drive ready signal led 59 is coming kindly help to solve the problem

[princeviju]

does any one have fanuc spares