VAMP Ltd
Feeder and motor manager
Technical description
VAMP 257
VM257.EN002
VAMP 24h support phone : +358 (0)20 753 3264
11
also available in the motor protection mode. Default value of
the application mode is the feeder protection mode.
The application mode can be changed with VAMPSET-software
or from config menu of the relay. Changing the application
mode requires configurator password.
NOTE!
Please see the next chapter for current based protection
function dependencies.
2.2.3.
Current protection function dependencies
The current based protection functions are relative to I
mode
,
which is dependent of the application mode. In the motor
protection mode all of the current based functions are relative
to I
mot
and in the feeder protection mode to I
n
with following
exceptions.
I
2
> (46), I
2
>> (47), I
st
> (48), N> (66) are always dependent on
I
mot
and they are only available when application mode is in the
motor protection.
2.3.
Manager functions
2.3.1.
Overcurrent protection (50/51)
The three-phase overcurrent function consists of three
separately adjustable overcurrent stages; stage I>, stage I>>
and stage I>>>.
The overcurrent function measures the fundamental frequency
component of the phase currents. The protection is based on the
highest phase current value.
The low-set stage I> can be configured for definite time or
inverse time operation characteristic. The stages I>> and I>>>
are configured for definite time operation characteristic (DT).
Inverse time operation (only for I>):
There are three ways to use the inverse time characteristics:
1.
using standard characteristics by selecting a curve family
(IEC, IEEE, etc) and a delay type (Extremely inverse, Short
time inverse, etc)
2.
selecting a curve family (IEC, IEEE, etc) and defining
parameters to the delay formula. This mode is activated by
setting delay type to ‘Parameters’, and then changing the
delay function parameters A..E.
3.
building the characteristics by setting 16 [current, time]
points. This mode is activated by setting curve family to
‘Prg1’, ‘Prg2’, or ‘Prg3’, thus there are maximum of 3
programmed curves available. The device interpolates the
values between given points with 2
nd
degree polynomes.