
Functions
2.6 Motor Protection
SIPROTEC, 7SJ61, Manual
C53000-G1140-C210-1, Release date 02.2008
114
Example: Motor with the following data:
The following settings are derived from these data:
The following settings are made:
IStart/IMOTnom
=
4.9
I MOTOR NOMINAL
=
0.6 A
T START MAX
=
8.5 s
MAX.WARM STARTS
=
2
#COLD-#WARM
=
1
For the rotor temperature equilibrium time, (address
4304
) a setting time of approx.
T Equal
= 1 min has
proven to be a good value. The value for the minimum inhibit time
T MIN. INHIBIT
depends on the motor
manufacturer, or by the user's requirements. It must in any case be higher than
4304
T Equal
. In this exam-
ple, a value has been chosen that reflects the thermal replica (
T MIN. INHIBIT
= 6.0 min).
The motor manufacturer's, or the requirements also determine also the extension factor for the time constant
during cool-down, especially with the motor stopped. Where no other specifications are made, the following
settings are recommended:
K
τ
at STOP
=
5
and
K
τ
at RUNNING
=
2
.
For a proper functioning, it is also important that the CT values and the current threshold for distinction between
stopped and running motor (address
212
BkrClosed I MIN
, recommended setting
≈
0.1
I
MOT.NOM
) have been
set correctly. An overview of parameters and their default settings is generally given in the setting tables.
Rated Voltage
V
Nom
= 6600 V
Nominal current
I
Nom
= 126 A
Startup current
I
STARTUP
= 624 A
Startup duration
T
Start max.
= 8.5 s
Permitted starts with cold motor
n
cold
= 3
Permitted starts with warm motor
n
warm
= 2
Current transformer
200 A / 1 A
Содержание SIPROTEC 7SJ61
Страница 368: ...Technical Data 4 22 Dimensions SIPROTEC 7SJ61 Manual C53000 G1140 C210 1 Release date 02 2008 368 ...
Страница 436: ...Appendix A 11 Measured Values SIPROTEC 7SJ61 Manual C53000 G1140 C210 1 Release date 02 2008 436 ...
Страница 438: ...Literature SIPROTEC 7SJ61 Manual C53000 G1140 C210 1 Release date 02 2008 438 ...
Страница 450: ...Glossary SIPROTEC 7SJ61 Manual C53000 G1140 C210 1 Release date 02 2008 450 ...
Страница 454: ...Index SIPROTEC 7SJ61 Manual C53000 G1140 C210 1 Release date 02 2008 454 ...