Toshiba G9 Installation And Operation Manual page 144

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F304
Dynamic Braking
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 G9 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 setup and enabled by connecting a
braking resistor from terminal PA to PB of the drive and providing the proper
information at F304, F308, and F309.
See the section titled Dynamic Braking Resistor Wire/Cable Specifications on
pg. 267 for more information on using the DBR system and for assistance in
selecting the appropriate resistor for a given application.
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 drive during
deceleration for a specified time in an attempt to prevent an Over-Voltage
Trip.
If the over-voltage threshold level setting of parameter
over 4 mS, an Over-Voltage Trip will be incurred.
Note: This parameter setting may increase deceleration times.
Settings:
0 — Enabled (Over-Voltage Stall)
1 — Disabled
2 — Enabled (Forced Shorted Deceleration)
3 — Enabled (Forced Dynamic Braking Deceleration)
136
Direct Access Number — F304
Parameter Type — Selection List
Factory Default — Off
Changeable During Run — No
Direct Access Number — F305
Parameter Type — Selection List
Factory Default — (ASD-Dependent)
Changeable During Run — Yes
F626 is exceeded for
G9 ASD Installation and Operation Manual
F305