Siemens MCC-3298 Benutzerhandbuch
24
3 Operating the SAMMS-LV Device
the motor trips and the Ground Fault LED illuminates until reset.
If you selected warning (OFF), the Ground Fault LED flashes as
long as the fault current exceeds the pickup level. Table 3.6 lists
the pickup levels for each overload size. Ground fault protection
is locked out for the overload class time.
Size
Pickup Current
Range
Default Pickup
Current
1A
1.5A
1.5A
1B
2A to 5A
5A
1C
2A to I
5A
2A
2A to I
10A
2B
2A to I
10A
3
2A to I
10A
4
2A to I
10A
5
5A to I
10A
6
10A to I
20A
* I
FLC
is the value of I
FLC
for OLR#2 if F3 is not set to OFF. If F3 is
OFF, I
FLC
is the value of I
FLC
for OLR#1.
Table 3.6 Ground fault pickup levels
Ground fault detection requires no additional external circuitry
or transformers. Ground fault detection for the SAMMS-LV
device is not available for grounded, three-phase systems or
single-phase applications. Ground fault pickup time is 360
msec.
3.25 Autoreset After a Trip (SAMMS-LVX
Only)
To restart the motor after a trip or a fault, you must first reset the
SAMMS-LVX device. You can reset the SAMMS-LV device in
one of two ways. First, press the Reset/Test button on the front
panel of the device. Second, enable the autoreset with HHC
function F8.
•
enable = ON
•
disable = OFF
With autoreset enabled, overload and external trips automati-
cally reset in 30 seconds after the trip. Once the reset occurs,
the SAMMS-LV device can be used to restart the motor, unless
the motor has reached its maximum temperature and has not
cooled down to the full-load level (start inhibit). Resetting after
a trip does not interrupt or otherwise affect the ongoing motor
thermal computations.
3.26 Emergency Restarting
In certain critical applications, you may want to restart a hot
motor even though restarting will damage or destroy the motor.
An emergency restart is a motor start that occurs after an
overload trip on maximum allowable winding or housing tem-
perature; but before they have cooled down to the full-load
temperature level (100%) or below. In other words, an emer-
gency restart is a start that occurs before the restart time
displayed by HHC function F10 reaches zero.
With the emergency restart function enabled (HHC function
F11), the motor can be restarted regardless of the residual heat.
If the SAMMS-LV device performs an emergency restart, the
winding and housing temperatures in the motor model compu-
tations reset to zero. Any time the motor is started, whether an
emergency restart or a normal start, the emergency restart
HHC function F11 is automatically reset to disable.
•
enabled = ON
•
disabled = OFF
3.27 Using the Hand Held Communicator
(HHC)
The HHC provides you with the capability to monitor and alter
various motor control and protection functions provided with
the SAMMS-LV device. For example, you can monitor and alter
control and protection settings such as on-delay time and
overload class. You can also monitor a variety of motor
operating conditions such as average current and elapsed
running time.
The SAMMS-LV device functions accessible through the HHC
depends upon the model of the SAMMS-LV device you are
using.
The HHCs small size makes it convenient to carry around and
use for communication with many SAMMS-LV devices. To use
the HHC, connect the HHCs cable, which uses a DB-9
connector, to the communication port located on the front
panel of the SAMMS-LV device. The HHC receives power and
control from the SAMMS-LV device. When connected to the
SAMMS-LV device, data is displayed on the HHC by a four-
character, seven segment liquid crystal display. When discon-
nected from the SAMMS-LV device, the HHC does not retain
or display data.
Once connected, you can access the functions provided by the
SAMMS-LV device through the use of the HHCs control keys.
The HHC has five (5) control keys: (F)unction, LIST, UP, DOWN,
and ENTER. The asterisk (*) key serves no function. The HHC
control keys are described in the following sections.
FLC
*
FLC
*
FLC
*
FLC
*
FLC
*
FLC
*
FLC
*