M-4172 Digital Motor Bus Transfer System

For Low Voltage (LV) Switchgear Applications.

  • Provides Automatic and Manual transfers of motor bus systems on Low Voltage Switchgears in power plants and industrial processing plants to ensure process continuity
  • Automatically selects Fast, In-Phase, Residual Voltage, and Fixed Time motor bus transfers, based on varying system conditions
  • Applicable for one way and bi-directional Manual transfers
  • Can be expanded to accommodate multiple breaker configurations
  • Integrated control, supervisory functions, sequence of events, and oscillograph recording in one device
  • Extensive commissioning tools, including ringdown analysis

Standard Features

Automatic Transfer: The digital Motor Bus Transfer System (MBTS) provides the following Automatic Transfer logic and features:

  • Transfer initiated by protective relay external to the MBTS
  • Automatic Transfer after a loss of the motor bus supply voltage based on the programmable undervoltage element. This provides a selectable backup feature if a protective relay transfer is not initiated.
  • Fast Transfer with adjustable phase angle limit, delta voltage limit and delta frequency limit
  • In-Phase Transfer at the first phase coincidence if Fast Transfer is not possible.
  • Residual Voltage Transfer at an adjustable low residual voltage limit if Fast Transfer is not possible
  • Fixed Time Transfer after an adjustable time delay
  • Programmable load shedding prior to initiating In-Phase Residual Voltage Transfer and Fixed Time Transfer
  • Verify the new source (the source to which the bus is being transferred) is healthy and within acceptable upper and lower voltage limits

Manual Transfer: When a Manual Transfer is initiated the digital MBTS provides the following:

  • Sync check functions with adjustable parameters
  • Hot Parallel Transfer if enabled (makebefore-break)
  • Fast Transfer, In-Phase Transfer and Residual Voltage Transfer (if the Hot Parallel Transfer is disabled)
  • Programmable load shedding prior to initiating Residual Voltage Transfer
  • Verify the new source (the source to which the bus is being transferred) is healthy and within acceptable upper and lower voltage limits

Circuit Breaker Control: The digital Motor Bus Transfer System includes the following Circuit Breaker Control features:

  • Control of two circuit breakers with two individual programmable breaker closing times
  • Three-breaker configuration can be provided by two M-4172 devices
  • Breaker status supervision
  • Breaker failure monitoring

Additional Standard Features

  • Sequential or Simultaneous Transfer Mode
  • Bus Phase Undervoltage (27B)
  • Frequency (81) and Rate of Change of Frequency (81R) for load shedding
  • Breaker Failure Source 1 and Source 2
  • Bus VT Fuse-Loss Detection (60FL)
  • Auto Trip
  • Auto Close
  • Four dry output contacts (two trip and two close) for Source 1 and Source 2, one lockout/blocking output contact, and 3 programmable output contacts (2 Form ‘a’ and one Form ‘c’)
  • Two Breaker Status 52b (or 52a) inputs for the Source 1 and Source 2 breakers, four programmable digital inputs
  • All functions can be enabled or disabled
  • Remote/Local control selection
  • Device ON/OFF Control Selection
  • M-3931 Human-Machine Interface (HMI) Module
  • M-3976 Status Module
  • IRIG-B time synchronization
  • Oscillographic recording
  • Two RS-232 ports (front and rear) and one RS-485 port (rear)
  • M-3871 ISScom® Communications and Oscillographic Analysis Software

Optional Features

  • RJ45 Ethernet Port utilizing MODBUS over TCP/IP Protocol or IEC 61850 Protocol
  • 5 A or 1 A models available
  • 60 Hz or 50 Hz models available
  • Available in vertical panel mount
  • Redundant Power Supply
  • External TCM and CCM available

M-0423 10′ RS-232 Serial Null-Modem Cable

M-0433 10′ USB to Serial Adapter with RS 232 Serial Null-Modem Cable (DB9 to DB9)

M-3908 Universal Contact Input Adapter

M-3933 10′ RS 232 Serial Modem Cable (straight through DB9 to DB25)