Rockwell Automation 284G ArmorStart - User Manual - Manual (Page 195)

Troubleshooting 10-7
Operation and Troubleshooting of the DB1 - Dynamic Brake
The DB1 Dynamic Brake option provides the following protection
features:
• DB Resistor Overtemperature Fault
• DB Overcurrent Fault
• DB Undercurrent Fault
• DB Switch Fault
• DB Open Fault
• DB VBus Link Fault
• DB Thermal Warning
• DB Comm Fault
DB Resistor Overtemperature Fault
The DB1 measures current continuously, and models resistor body
temperature based on measured current and resistor model
parameters. The DB1 not only calculates the present resistor body
temperature, but also predicts the future resistor body temperature.
The resistor overtemperature level is based on the predicted future
resistor body temperature, not on the present resistor body
temperature. This fault is disabled when parameter 182 (DB Resistor
Sel) is “Disabled.
Troubleshooting – DB Resistor body temperature is too hot. Allow
resistor to cool.
DB Overcurrent Fault
The DB1 compares each current measurement against the Max
Current Level. If 5 consecutive samples are above the Max Current
Level, then a fault is recorded. This fault is intended to notify the user
if the DB resistance is lower than expected. This fault is disabled
when parameter 182 (DB Resistor Sel) is “Disabled.
Troubleshooting – DB monitor has measured a DB current higher
than expected. Turn off all power to unit. Allow at least 3 minutes for
capacitors to discharge. Disconnect DB resistor from ArmorStart
control module. Caution- DB resistor may still be hot. Measure DB
resistor value at the connector with an ohmmeter. DB resistor value
should be within the limits defined in Table 10.4. If DB resistance
value is within limits, replace control module. If not, replace DB
resistor.