Specifications

Neutral pole protection
M-PRO17: Factory-set to 50% or 100%
M-PRO20-40: Customer selectable between ‘OFF’,
50% and 100%.
Thermal memory
To protect against unacceptable recurring or cyclic
overloads the M-PRO will track and memorise the
thermal effects of load current while the breaker is
on line. Tripping will be initiated when the
cumulative thermal effect of cyclic overloading
reaches a predetermined level.
M-PRO20: Adjustable time constants (auxiliary
power supply mandatory)
M-PRO30-40: Adjustable time constants (auxiliary
power supply included)
Trip alarm switch
M-PRO17-40: this 1NO switch is operated by the
protection management unit trip mechanism when
the M-PRO has initiated a trip. Tripping is indicated
until the reset button on the M-PRO is pressed. In
case of automatic reset an impulse will be generated
RESET Function
M-PRO17: manual reset function only
MPRO20-40: manual or auto reset function
Plant Associated Memory Module
M-PRO20–40 includes a plant associated memory
module (PAMM), fitted remote from the protection
unit that stores the M-PRO settings. This feature
reduces set-up time by down loading the original
data if the M-PRO is replaced or the moving portion
of the ACB is changed. The new unit will not require
re-configuration while ensuring error-free
replacement and maintenance.
Adjustment method of setting
M-PRO17: Front panel rotary switches
M-PRO20-40: Front panel keypad, LCD display
Inputs
M-PRO30 & 40 are provided with four opto-coupled
remote inputs to initiate alarm signals or tripping of
the circuit breaker in response to signals indicating
a change in the state of devices remotely positioned
in the system.
The supply voltage of the remote inputs are 24/48V
DC (MPRO 30L or MPRO 40L) and 110/250V AC or
110/130V DC (MPRO 30H or MPRO 40H).
Outputs
M-PRO30 & 40 are provided with four relay outputs
to permit remote indication of changes in the state
of the circuit breaker and its protection, e.g. M-PRO
initiated trip / watchdog alarm / breaker main
contact maintenance alarm / remote fault / pre-trip
alarm/load monitoring.
This facility may also be used to transmit a remote
trip signal to a High Voltage circuit breaker.
An external power supply is required to permit
remote output facilities.
Load Monitoring
M-PRO30–40 offers two alternative facilities of
monitoring the load, pre-alarm or load shedding.
Pre-trip alarm: This alarm will provide a warning
when the current measured is above 1.1x Ir and the
thermal content is above 60% thus indicating that a
trip is likely to occur.
Load shedding: Load shedding will have two user
configurable current levels, the level which shedding
will start, and the level at which shedding will stop
(auxiliary power supply mandatory).
Communication
M-PRO40: By means of a RS485 4-wire serial link
using a MODBUS protocol, M-PRO protection units
can be linked for remote communication to provide
a complete system management and control.
Communication occurs in both directions.
Remote switching – each unit can be remotely
opened and closed
Remote adjustment – user settings and inputs may
be altered by remote command
Monitoring – ammeters, load monitoring,
operations counter, existing faults, trip history
A.10
Technical overview
A
GE Power Controls