Rockwell Automation 1557 MEDIUM VOLTAGE AC DRIVE - Manual (Page 270)

10-28 TROUBLESHOOTING
1557-UM050F-EN-P – June 2013
Replacing Snubber Diodes
Snubber diodes can be replaced without having to remove the heatsink assembly from the drive. The
circuit board assembly must be removed as described previously in REPLACING THYRISTORS-
MACHINE SIDE CONVERTER part 1. Remove 1/4 in. nuts of the heatsink to snubber diode link at the
front of the heatsink. Remove the M8 bolts of the diode clamp. The clamp and heatsink to diode link can
now be removed (see Figure 10.5).
Figure 10.5 – Replacement of Snubber Diode
Replace the snubber diode, noting its orientation and ensuring that there is a thin film of electrical joint.
Reassemble clamp and link. Torque the M8 bolts of the clamp evenly until the tabwasher can just be
rotated with finger touch.
Snubber Diode