02 IMPORTANT SAFETY INFORMATION
3BHS213401 E01 REV H ACS1000 AIR-COOLED USER MANUAL 25/184
Figure 2-3: MCB opening timing diagram
In order to meet the stipulated safety requirements, ABB recommends of the following:
- MCB equipped with 2 independent opening coils
- MCB equipped with an opening coil and an undervoltage coil for monitoring of the control
voltage
- 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.
2.8.3 Maintenance recommendation
The MCB trip circuits should be checked annually.
(1) Short-circuit occurs
(2) Open and or trip command is set at the drive control output
(3) No further damage to the drive
(4) No hazard to personnel
(5) Maximum protection trip time
(6) Maximum safety trip time
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