Fanuc spindle drive

It helps to know more specifics about the drive/motor package, but I have some general ideas.

if this an analog or digital system? PWM or SCR type?

In both cases, look at deceleration rates. Decel rates are adjusted in the drive firmware or Executive system for digital systems and by potentiometers on analog systems. If the system is having to dump a lot of back EMF (generated by shorting the windings with the transistors you mention that go out), the power has to be dissipated in the transistor/resistor circuit. By spreading the decel rate over a longer period of time, the maximum rating is less likely to be exceeded. If the decel rate cannot be modified, use a transistor with a higher power dissipation rating. Make sure the heat-sinking is good by using the proper heat sink compound. Depending on the circuit, it may require a electrically conductive compound. (this is most common with SCR type drives not transistor drives.)

Hi,

we shot all three H-bridges in the AC motor of a wafer dicing saw by too fast decelerating and creating a very large overvoltage: as the last post states!

May be you have an unintended brake done with this spindle?

RHABE

Dear ashutosh,

It seems you are blowing transistor modules at random. Please follow these steps:

1. If you blowing the same set of transistor modules then there is some defect in the

driver area.

2. On the other hand if you blow diff transistor modules then you should focus on the

current feedback modules (Iamp modules on the drive board) Please change them

you will get the result.

all the best.

Prabhu