Pre-Charge Using Sop; Electric Shock Hazard; Limiting Function (Applicable To All Precharge Types); Preconditions For Pre-Charge Types 1 To 3 - Siemens SINAMICS PERFECT HARMONY GH180 Function Manual

Advanced Operating Functions

8.18 Pre-charge using SOP

8.18 Pre-charge using SOP
8.18.1

Electric Shock Hazard

Electric Shock Hazard
During pre-chargeelectric shock hazardDuring pre-charge, medium voltage is present on the
primary side of the input transformer and upstream device, even though the MV contactor is
not closed.Stay clear of the primary side of the input transformer to avoid death or serious
injury.
8.18.2

Limiting Function (applicable to all precharge types)

A limiting function that will prevent multiple, back-to-back precharge attempts has been added
and affects all precharge types. This function will prevent successive precharge attempts from
occurring any more frequently than once per minute or 5 per hour. This is part of the permissive
algorithm used in Type 5 & 6, the output of which sets the "DriveReadyToPrecharge_I" flag.
This is disabled by default and can be enabled by setting the "PrechargeLimitationEnable_O" SOP
flag to true. If more than one attempt is made within a minute, the message "Precharge: too
often - more than 1 per minute!" will be produced. More than 5 attempts within an hour will
produce the message "Precharge: too often - more than 5 per hour!" Both messages will appear
in the event log along with the "not ready" alarm message.
Should a precharge attempt be made when DriveReadyToPrecharge_I is false, an alarm "Not
ready to precharge" is set and displayed on the keypad. The alarm will be cleared when the
DriveReadyToPrecharge_I condition is valid again – but must be acknowledged as with other
alarms. Therefore, this flag should be used in the logic to create the precharge attempt. These
conditions define the alarm active: Alarm active when precharge enable is true, drive is not ready
to precharge, no precharge fault active, and drive not actively in precharge.
This flag will not be set true if the drive has experienced precharge once in the past minute, or
5 times in the past hour. If an attempt is made to precharge with the DriveReadyToPrecharge not
set to true, then a message stating the drive is not ready will be displayed on the keypad and
recorded in the event log. The precharge start MUST be removed before attempting again, and
DriveReadyToPrecharge must return to true. Then the drive can respond to precharge.
8.18.3

Preconditions for Pre-charge Types 1 to 3

Aside from safety concerns, and assuming that input power is available, the following conditions
need to be met to initiate pre-charge types 1 to 3. Monitor the entire pre-charge sequence
through an externally connected monitor or through the Debug Tool set to the "Drive Misc Status
Flags 2" using Ctrl-Y on the keyboard or menu selection in the tool.
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