Maintenance Recommendation - ABB ACS5000 User Manual

ABB
Short-circuit occurs
Open and or trip command is set at the
drive control output
No further damage to drive
Max. protection trip time
Fig. 2 MCB opening timing diagram

Maintenance recommendation

5k A UM
■ The maximum opening time of the MCB must never exceed the
product or project-specific maximum time defined in the MCB
specifications. Typical maximum values for the drive are defined as
follows:
■ Maximum protection trip time: 75 ms
The maximum protection trip time is the maximum permitted
breaking time (open and arcing) of the breaking device after the
open command has been initiated to prevent further damage to
the drive, eg, diode failures.
■ Maximum safety trip time: 500 ms
The maximum safety trip time is the maximum permitted time to
ensure safe disconnection of the main power supply to prevent
any hazard to personnel.
Max. safety trip time
In order to meet the stipulated safety requirements, it is recommended
that:
■ the MCB is equipped with two independent opening coils, or
■ the MCB is equipped with one opening coil and an undervoltage coil
for monitoring of the control voltage, or
■ an upstream protection coordination scheme is provided which uses
the "breaker failure" (ANSI 50BF) signal to automatically trip the
upstream breaker, in case the MCB does not open. The upstream
breaker must open within the maximum safety trip time after a failure
has occurred.
The MCB trip circuits should be checked once yearly.
3BHS221906 ZAB E01 Rev. D
No hazard to personnel
3 (4)