Centroid Community CNC Support Forum

Ok I got it. Thanks, very helpful.

To further cloud the question of whether to have Emergency Stop break the line power, or just the enables:

If you break the enables and leave line power on, then the inverter can provide dynamic braking (decelerating the spindle and dumping the power into the braking resistor).

If you cut off line power, most inverters will free coast to a stop. This will result in a much longer time before sharp objects stop moving. So arguably, it is safer to leave the line power on and only break the enables.

Codes and standards seem to leave this decision up to the system designer, who is supposed to assess risk and choose the safest design.

On high-power, high-end systems lately I have been installing an off-delay timer relay in my emergency stop circuit. Pressing emergency stop immediately opens a control relay which breaks all the drive enables. Three to five seconds later the off-delay relay opens, which opens the large E-stop contactor(s) and cuts line power to the drives. This provides the extra safety of actually removing power from the drives, while still allowing time for active deceleration to a stop. It also allows the operator to press and release Emergency Stop (to clear a fault) without cycling line power. Cycling line power is hard on drives, because of the high inrush to charge the capacitor banks.

Thanks guys. Scott, I am just taking notice that the wire runs through the "NO" concact on the e-stop contactor. Correct? I just thought it ran through the other lines. T4. Ect. Also, with this wiring configuration do I still use the J28 jumper? Thanks

You can use either a NO pole (such as T4) or an NO auxiliary contact. The difference between the two is that the auxliary contacts are intended to switch low(er) current while the poles can switch loads up to the rating of the contactor (such as the DC servo power)