P9 ASD Installation and Operation Manual 137
Dynamic Braking Selection
Program Protection Dynamic Braking
This parameter Enables/Disables the Dynamic Braking system.
Settings:
0 — Off
1 — On with Overload Detection
2 — On without Overload Detection
Dynamic Braking uses the transistor IGBT7 to dissipate the bus voltage when
required.
IGBT7 is a standard item on the 25 HP and below P9 ASD 230-volt systems
and is standard on the 400 HP and below for the for the 460-volt systems.
IGBT7 is optional for all remaining systems.
Dynamic Braking
Dynamic Braking is used to prevent over-voltage faults during rapid
deceleration or constant speed run on cyclic overhauling applications.
Dynamic Braking dissipates regenerated energy in the form of heat. When
using a DBR, use thermal protection.
The resistive load is connected across terminals PA and PB (non-polarized).
Using a low-value, high-wattage resistance as a load for the generated current,
the resistive load dissipates the induced energy.
Dynamic Braking helps to slow the load quickly; it cannot act as a holding
brake.
The Dynamic Braking function may be set up and enabled by connecting a
braking resistor from terminal PA to PB of the ASD and providing the proper
information at F304, F308, and F309.
See the section titled Dynamic Braking Protection on pg. 280 for additional
information on using the DBR system and for assistance in selecting the
appropriate resistor for a given application.
Direct Access Number — F304
Parameter Type — Selection List
Factory Default — Off
Changeable During Run — No
Over-Voltage Limit Operation
Program Protection Stall
This parameter enables the Over-Voltage Limit function. This feature is used
to set the upper DC bus voltage threshold that, once exceeded, will cause an
Over-Voltage Stall.
An Over-Voltage Stall increases the output frequency of the ASD during
deceleration for a specified time in an attempt to prevent an Over-Voltage Trip.
If the over-voltage threshold level setting of F626 is exceeded for over 4 mS, an
Over-Voltage Trip will be incurred.
The F452 (Power Running Stall Continuous Trip Detection Time) setting may
affect the performance of this setting.
Note: This setting may increase deceleration times.
Settings:
0 — Enabled (Over-voltage Stall)
1 — Disabled
2 — Enabled (Forced Shorted Deceleration)
3 — Enabled (Forced Dynamic Braking Deceleration)
Direct Access Number — F305
Parameter Type — Selection List
Factory Default — (ASD-Dependent)
Changeable During Run — Yes
F304 F305
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