Spindle Deceleration Problem

[Hash01]

Can anyone tell me where to look on a VACIII D11 for probable faults on spindle winding change over. I replaced an IGBT module and some transistors on this spindle drive a few monthes ago. It worked to get me going but when I try to come off any rpms over 4200 I get an alarm. To solve the problem and cut parts I just step it down in 500 rpm increments with 2 second dwells between the changes. I would rather just fix it correctly.

[Algirdas]

there are powerfull resistors, must be on heat sink. Follow the wires to heat sink and you will find these resistors.
It's not likely, that resistors are damaged itself. Maybe contacts, maybe semiconductors. There are some semiconductor components involved also - maybe some power transistor module (like IGBT) and set of diodes.
Maybe contactor (similar to motor starter) is involved in braking also.

[neilw20]

Will it run in reverse? Sounds like current limit in reverse direction is bombing out.

[underthetire]

What machine? What alarm #?

[iecs]

Your regeneration is not working on the drive. Most likely You are getting Over-voltage alarm on the drive. When You replaced IGBT's You didn't repair boards. IGBT's went bad due to the problem on the top board (main control board) and when IGBT's blew they caused bottom board to fail. Just last week repaired one like that.