13
SECTION 2 PROTECTION UNITS
M-PRO 17 Protection Unit
Front Panel
Healthy LED
A green ‘healthy indicator’ is continuously flashing at the pace
of a ‘heart beat’ when the M-PRO is powered and the
operation status is normal.
Reset button
Factory set to ‘Manual’ (‘Auto’ reset upon request.) In the
event of a fault, M-PRO will trip the circuit breaker and the
button will eject from its normally flush position.
The fault must be cleared and the button pushed to reset
before the circuit breaker can be re-closed. If ‘Auto’, the reset
button will remain in its flush position and, after clearance of
the fault, M-PRO will reset itself to permit re-closure of the
breaker.
Test port
A 15-way ‘D’ type test port at the bottom of the front panel
accommodates a plug-in Test Box.
Adjustable slotted switches
An easy-to-use set of screwdriver adjustable rotary switches
enables adjustment of the protection settings. Valid switch
settings are in accordance with the front panel graduation
marks and are defined by a positive ‘click’ action.
The long time protection pickup Ir, the short time pickup Im,
the short time delay and optionally the earth fault Pickup If and
earth fault delay.
Front Panel MIMIC
Mimic of the operating characteristic
The M-PRO17 provides long time protection, short time
protection, making current release/high set instantaneous
short circuit protection and earth fault protection. Protection is
provided on all three phases and neutral (on four pole circuit
breakers). The overall protection scheme is shown on the
following diagram:
Current
Time
Key
Long Time
Protection
Short Time
Protection
MCR/HSISC
Earth Fault (optional)
I
I
Protection
switches
Protection
switches
(earth fault
option)
Manual
reset button
Protection
mimic
Protection
mimic
(earth fault
option)
Healthy
LED
Multi-pin
test port
