Siemens LMV5 Quick Start Manual page 139

VSD faults Phase 10
If VSD faults are occurring in Phase 10 (home position),
check the setting of Parameter "ReleaseContctVSD".
If this is set to open, the LMV52 will simply open the run / stop contact
after postpurge is complete.
If this is set to closed, the LMV52 will keep the run / stop contact closed
after postpurge is complete.
1) Depending on how the VFD is configured, opening the run / stop contact after postpurge
could engage a DC brake in the VFD to slow down the blower rapidly.
If the VFD does not have this capability, opening the run / stop contact will let the blower
freewheel and coast down after postpurge is complete.
If the run / stop contact is kept closed after postpurge is complete, the VFD should bring the
bower RPM down to the home position in a controlled manor.
2) Whichever option is selected, the goal is to have the blower motor RPM correct at home
position, which is phase 10. Typically, home position is set to 0% VSD. If this is the
case, this means that the blower must be spinning at less than 8% of the standardized
RPM by the end of Phase 10 (8% of 3585 RPM = 287 RPM). The LMV52 will wait
approximately 20 seconds in Phase 10 for the proper speed (if set to a percent grater
than 0 % VSD) or the less than 8% speed (if set to 0 % VSD) to be reached before
locking out.
3) If this problem is occurring, verify that "ReleaseContctVSD" is set to closed.
If this does not help, reducing the blower speed and / or opening the air damper further in
postpurge will help slow the blower.
If the problem is still encountered, setting "ReleaseContctVSD" to open and adding DC
braking on the VFD typically cures the problem.
Random error codes or AZL not on bus
If random error codes occur or if "AZL not on bus" problems occur when operating the VFD, check
the following:
1) Ensure that the LMV52, the VFD, and the three phase motor are grounded to chassis
ground.
Also ensure that Pin3 of the AGG5.210 transformer and Pin X52.4 of the LMV52 are
grounded to chassis ground.
2) Ensure that the wires between the VFD and the blower motor are in some type of metal
conduit (flex or hard conduit).
This is important since these wires are a rich source of EMF (Electromagnetic Field)
and can adversely affect the LMV52, causing many different error codes.
Metal conduit will contain the vast majority of the EMF.
LMV5 QSG Rev 4 Sec 5 Pg 13 www.scccombustion.com