Speedfax 2017

Molded Case Circuit Breakers
Digital Solid State Sentron Sensitrip IV Series
Revised on 05/31/18
Technical
(I r )
(t ld )
(I i )
A. Adjustable “Continuous Amps”
Rating Switch
All Sensitrip IV solid state molded
case circuit breakers have an adjustable
ampere rating switch. Adjustments
made to this switch change the
continuous current rating of the breaker.
B. Adjustable “Long Time
Delay” Switch
All Sensitrip IV circuit breakers have
an adjustable long time delay switch to
allow for selection of long time delays
of fixed time intervals at six times the
setting of the adjustable “continuous
amps” rating switch.
C. Adjustable “Instantaneous
Pick-Up” Switch
Sensitrip IV circuit breakers with an
adjustable instantaneous pick up
switch allow selection of a specific
instantaneous trip setting.
(I r )
Time
6 x Ir
(t ld )
Time
(I sd )
Time
D. Adjustable “Short Time
Pick-Up” Switch (Optional)
Sensitrip IV circuit breakers with
an adjustable short time pick-up
switch allow for selection of short
time pick-up in a range from 1.5
to 10 times the setting of the
maximum current rating.
E. Adjustable “Short Time
Delay” Switch (Optional)
Sensitrip IV circuit breakers with
an adjustable short time pick-up
switch also contain a switch for
adjustment in time delay. The
adjustable short time delay switch
allows for either of two modes of
short time delays. One range of
settings enables the breaker to be
set for fixed time delays and the
other range of settings enables
the breaker to be set for short time
delays based on l 2 t curves.
(t sd )
(Ig)
3 x Ig
(t g )
Adjustable “Ground Fault Pick-Up” Switch
Sensitrip IV circuit breakers containing the
optional equipment ground fault protection
have a ground fault pick-up setting. The
ground fault pick-up settings allow for one
of three time delays based on I 2 t curves.
For 3-phase, 4-wire systems, an external
neutral transformer is required with an
ampere rating equal to the trip unit ampere
rating.
l n
l r
= Maximum circuit breaker ampere rating
= Continuous current rating expressed in amperes
I i = Instantaneous pickup expressed in amperes
I sd = Short time pickup expressed in multiples of I r
I g = Ground fault pickup expressed in amperes
t sd = Short time delay - either fixed or I 2 t time delay
function
t ld = Long time delay - I 2 t time delay function
t g = Ground fault delay - I 2 t time delay function
7
MOLDED CASE
CIRCUIT BREAKERS
Examples of Adjustment Settings
Catalog Number SLD6A600LI
Frame
Switch 1 Swtich 2 Switch 3
Rating (I n )
Continuous Current Setting (I r ) Long Time Delay Setting (t ld ) Instantaneous Pickup Setting (I i )
Setting 600A 200 2.5 750
Description 600A max current rating 200A 2.5 sec to trip @ 6 x I r [6 x 200A = 1200A] 750A
Catalog Number SLD6A600LSIG
Switch 1 Switch 2 Swtich 3 Switch 4
Frame
Short
Rating Cont. Current Long Time Short Time Instantaneous Time Delay
(I n )
Setting (I r ) Delay Setting (t ld ) Pickup Setting (I sd ) Pickup Setting (I i ) Setting (t sd )
Ground Fault
Pickup Setting
(Ig)
Ground Fault
Delay Setting
(tg)
Setting 600A 300 10 1.5 5 0.1 36 [.18] 36 [.18]
Description
600A max
current rating
300A
10 sec @ 6 x Ir
[6 x 300A = 1800A]
1.5 x Ir
[1.5 x 200A = 300A]
5 x In
[5 x 600A = 3,000A]
0.1 sec
Ig = 36 x 10
[36 x 10 = 360A]
0.18 sec @ 3 x Ig
[3 x 360 = 1,080A]
7-148
Siemens Industry, Inc. SPEEDFAX Product Catalog