Protections
97
8.7 OVER CURRENT ALARM
The overcurrent alarm combines a simple warning trip level with a fully functioning IDMT curve for
thermal protection.
8.7.1 IMMEDIATE WARNING
If the
Immediate Warning
is enabled, the DSE8600 Series controller generates a
warning alarm
as
soon as the
Trip
level is reached. The alarm automatically resets once the generator loading current
falls below the
Trip
level (unless
All Warnings are latched
is enabled). For further advice, consult your
generator supplier.
8.7.2 IDMT ALARM
If the
IDMT Alarm
is enabled, the DSE8600 Series controller begins following the IDMT ‘curve’ when
the
trip
level is passed.
If the
Trip
is surpassed for an excess amount of time the
IDMT Alarm
triggers (
Shutdown
or
Electric
trip
as selected in
Action
).
High current shutdown
is a latching alarm and stops the Generator.
Remove the fault then press Stop/Reset
to reset the module.
High current electrical trip
is a latching alarm and removes the generator from the load, before
stopping the Generator after the off load
cooling
timer.
Remove the fault then press Stop/Reset
to reset the module.
The higher the overload, the faster the trip. The speed of the trip is dependent upon the fixed formula:
T = t / ( ( I
A
/ I
T
) – 1 )
2
Where:
T is the tripping time in seconds
I
A
is the actual current of the most highly loaded line (L1 or L2 or L3)
I
T
is the delayed over-current trip point
t is the time multiplier setting and also represents the tripping time in seconds at twice full load (when I
A
/ I
T
= 2).
Factory settings for the
IDMT Alarm
when used on a brushless alternator are as follows (screen
capture from the DSE Configuration Suite PC software :
These settings provide for normal running of the generator up to 100% full load. If full load is
surpassed, the
Immediate Warning
alarm is triggered, the set continues to run.
The effect of an overload on the generator is that the alternator windings begin to overheat; the aim of
the
IDMT alarm
is to prevent the windings being overload (heated) too much. The amount of time that
the set can be safely overloaded is governed by how high the overload condition is.
I
T
(Trip setting
value)
t
(time
multiplier)
Summary of Contents for DSE8610
Page 47: ...Installation 47 4 2 2 3 PHASE 4 WIRE WITHOUT EARTH FAULT PROTECTION...
Page 51: ...Installation 51 4 3 2 SINGLE PHASE WITHOUT EARTH FAULT...
Page 53: ...Installation 53 4 3 4 2 PHASE L1 L2 3 WIRE WITHOUT EARTH FAULT...
Page 55: ...Installation 55 4 3 6 2 PHASE L1 L3 3 WIRE WITHOUT EARTH FAULT MEASURING...
Page 118: ...Intentionally Left Blank 118...
