Problem- Spindle inverter failing?

[rickt395]

Hi all.

I have a 1998 Fadal 4020, single phase, AMC spindle inverter. I was running a proven program when in the middle I heard a racket from the machine and all came to a stop. The spindle was coasting to a stop. That took 2 to 3 minutes because I was running at 10,000 at the time. On the control I got the error message "Spindle would not stop". A spindle stop was not commanded in the program.

I jogged back to cold start position, did a CS and the spindle would start.

Changed the speed to 5,000 rpm and started over and about 4 minuted into the program the same thing happened. This was at a different point in the program. This time I checked the inverter and the fault led was red. All other led's were normal. I got back to the cold start position, restared the program and 3 to 4 minuted the same problem.

I check all connections and plugs and all seemed OK. After waiting about an hour I was able the complete the part, but that only was about another 10 minutes of run time.

The spindle motor was replaced about 5 months ago because the insulation was degrading.

Is this the sign of a failing inverter or somethine else? What else can I or should I check?

Thanks in advance
Rickt

[Neal]

If it happened during Rigid tapping, then I suspect that you may also have coded a G84.2 before your R/tap line. Only the older machine required this code as a sync calibration for the spindle motor and spindle hall switch. The newer machine have that calibration built in to the G84.1. The G84.2 will sometime cause the "spindle will not stop" error code. If this is the case, then just delete the G84.2 from your program.

Neal

[rickt395]

Hi Neal

I wasn't tapping at the time, just engraving some part numbers. My machine doesn't have rigid tap.

Any other ideas?

Thank you
rickt

[alex gitzel]

It sounds like the regenitive resistors are not working.there is a fuse on the side of the invereter check it,and then ohm r1 and r2 wires comming out of the drive.take the wires out and ohm across them should be at least 6ohms ususaly around 10.if these are ok then the regen components inside the drive may have failed,i have seen it happen a few times.

[Neal]

Most of the drives that Fadal uses have either 19 or 13 ohm regen resisters. A very few were 20+ ohms. If there are dual resisters then checking both of them together would read half of that value. Also check the resisters to ground for any shorts.

Neal

[rickt395]

Thanks for the help, but the spindle not stopping is not the main problem. The main problem is the spindle stopped abruptly without being commanded to do so. When this happens the inverter faults and then the spindle coasts to a stop.

I have checked and tightened all connections, checked the resistors and resistor fuse, checked the pins and wires on the plugs and the encoder plug at the connector box at the motor. I didn't find anything that seemed out of place, but I have had the spindle running for about 6 hours without a problem. I will now get a real program running and see what happens.

If it faults out again I will order an inverter.

Thanks to all for the help.

rickt

[Neal]

When the control goes into E-stop the all power is removed from the drives. That will cause the spindle to coast down to a stop. Before you replace the expensive vector drive ensure that there is no issue with the spindle magnet Hall Effects switch. Check connections and/or contamination(chips).

Neal

[alex gitzel]

You should also reseat the spindle control card and make sure the gold bullet plugs are all tight on the card.

[rickt395]

I have reset the spindle driver board in the back plane and the cables going to the board.

I will check the connections on the spindle magnet and the magnet for chips. A question for Neal, how much clearance should there be between the magnet and the pickup?

At this time things are running. I don't know if I had a bad connection that I fixed or not. I never found anything the looked bad. This seems to one of those times that if it ain't broke, you can't fix it.

Thanks again

rickt

[Neal]

The air gap between the Hall switch and the maagnet should be between .030" and .050".

Neal