Triac PC Atc Blowing Fuses

[blatter]

After lots of searching i am now the proud owner of a Triac PC with Atc 1996 that was upgraded with a nextstepES in 2006. i have made a couple of test pieces in Aluminium which have turned out well. But I am a bit puzzled about it starting to eat Fuses, seems to be related to the spindle. it has blown the fuse on the sprint on 1 occasion, F1 4 times and tripped the house once at the same time as blowing F1. i have used a 63mm slab mill 0.5 depth of cut, 40 mm wide at 500mm/min and it coped fine at 1000RPM, i can hear the rpm slow slightly then it picks back up again. but using a 3mm drill at 3500RPM and 150mm/min chip breaking took out 2 F1's. Changed the routine to a peck drill with full retract and it managed the next 9 holes ok. I would have thought a 1.5hp spindle motor would have snapped the 3mm drill before blowing out a 10amp fuse. Any advice would be welcome

Paul

[blatter]

Not quite sure why, but it seems to have sorted itself out now. Touch wood!

[Denford Admin]

The spindle may have just loosened up

[blatter]

its Possible, im now roughing aluminium at 1000mm/min 3200rpm 2.7mm depth using a 12 ripper at 65% step over with ease
i have however noticed that tapping a M8x 1.25 thread at 250rpm has to have a feed of 420mm/min so i think the spindle is running too fast 250x1.25 should only be 312mm/min. i have ordered a laser tacho to check the spindle speed
i have checked the feed on all axis seperatly in MDI by timing a 100mm move at a feed of 100mm/min and they are correct to the second

[Denford Admin]

Just to warn you that I don't think those motor/drives are that great at low speed anyway, ie, don't expect too much or for it to be accurate

[blatter]

Well the Digital Tacho arrived today and i think i found the problem. At a programmed S4000 rpm the Spindle was was actually running at 4906rpm, so probably drawing too much current hence the fuses blowing. The milling i have done recently was done at a max of S3200 which worked out at just under 4000rpm, so i presume within the max speed and current.

Anyway with the help of a previous post viewtopic.php?f=47&t=1657 on how to setup the Triac spindle, i have made the adjustments and its now so close its not worth playing with the adjustment any more.

Paul

[Denford Admin]

don't expect too much or for it to be accurate

I'll take that comment back