Beckwith Electric M-4272 Digital Motor Bus Transfer System
Beckwith Electric M-4272 Digital Motor Bus Transfer System
The M-4272 Digital Motor Bus Transfer system provides automatic and manual
transfers of motor bus systems in power plants and industrial processing plants,
to ensure process continuity. For any critical application in which losing power
is unacceptable, the M-4272 seamlessly handles transfer to backup power sources.
It automatically selects fast, in-phase, residual voltage, and fixed time motor bus
transfers, based on system conditions.
It is applicable for both one way and bi-directional manual and automatic transfers
and can be expanded to accommodate multiple breaker configurations.
Additional features of the M-4272 include:
• Multiple setpoint profiles for various application requirements.
• Integrated control, supervisory functions, sequence of events, and oscillograph
recording.
• Extensive commissioning tools, including ringdown analysis.
• Optional M-3919A Graphic Display Unit (GDU) and Touch Screen Human Machin
Interface (HMI) for communicating with one or two M-4272 units.
• Optional M-5072 Retrofit Kit for M-4272 Replacement of M-0272/M-0236B Analog
Transfer Logic Controller.
Intertie Protection M‑3520 Integrated Protection System®
• Integrated Protection System for DER Intertie, providing:
Loss of parallel utility operation protections
Abnormal power flow protections
Comprehensive suite of phase and ground
fault backed protections
Abnormal operating protections
Reconnect and Sync Check functions
• Microprocessor-based Intertie Protection Relay integrates
protection, metering, monitoring and waveform capture
• Provides 18 base protective relay functions and
3 optional protective functions
• Local and remote serial communications capabilities, plus
IRIG-B interface
Standard Functions
• Sync check with Phase, ∆V and ∆F with deadline/deadbus options (25)
• Phase undervoltage (27) protection
• Neutral over/undervoltage (59G/27G) protection
• Sensitive dual-setpoint, reverse power detection (32)
• Sensitive negative-sequence overcurrent protection and alarm (46)
• Negative sequence voltage (47)
• Instantaneous overcurrent (50) protection
• Instantaneous neutral overcurrent (50G) protection
• Three-phase inverse time overcurrent (51V) with voltage control/voltage restraint
• Neutral inverse time overcurrent (51G) protection
• Phase overvoltage (59) protection
• Peak overvoltage (59I) protection
• VT fuse-loss detection and blocking (60FL)
• Directional inverse and definite time phase overcurrent (67)
• Directional inverse and definite time neutral overcurrent (67N)
• Reconnect enable (79)
• Over/Underfrequency (81 O/U)
Optional Functions
• Dual-zone phase distance protection for phase fault backup (21)
• Out of Step (78)
• Rate of change of frequency (81R)
