Siemens SIPROTEC 7SJ62 Handbuch Seite 33

3rd step
4th step
7SJ62/63/64 Additional Information
C53000-B1174-C170-1
Motor starting time supervision
STARTUP CURRENT =
(Address 4102)
Parameter 4102 STARTUP CURRENT = 4.16 A
Parameter 4103 STARTUP TIME =
For reduced voltage, the startup current is also reduced almost linearly. At 80 % of the
rated voltage the startup current thus reduces to 0.8 ⋅ I
The threshold for detection of a motor startup must lie above the maximum load
current and below the minimum startup current. If no other influencing factors are
present (peak loads), the value (I MOTOR START set at address 1107) may be a
median value:
For the rated current holds:
3.3 A
--------------------------------- -
I =
STARTUP-sec
Parameter 1107 I MOTOR START = 2.1 A
Restart inhibit
Parameter 4302 IStart/IMOTnom =
Parameter 4303 T START MAX =
Parameter 4304 T Equal =
Parameter 4305 I MOTOR NOMINAL = 0.8 A
Parameter 4306 MAX.WARM STARTS = 1
Parameter 4307 #COLD-#WARM =
Parameter 4308 Kτ at STOP =
Parameter 4309 Kτ at RUNNING =
Parameter 4310 T MIN. INHIBIT =
The heating time constants of the motor must be indicated by the manufacturer. For
the cooling time we recommend to set three times the value of the heating time (this
corresponds to a cool-down to < 5 %).
start current
------------------------------- - I
⋅
N CT sec
I
NCT prim
5.2 160 A
 ⋅
---------------------------- 1 A
=
⋅

200 A
8.2 s
160 A
-------------- -
= 0.8 A
200 A
+ 0.8 A
2.1 A
≈
2
5.2
8.2 s
1 min
1
10
5
6.0 min minimum inhibit time
Setting Example

= 4.16 A

= 3.3 A.
START MAX
starting current related to the
rated current
maximum allowed starting time
rotor temperature equilibrium
time
= (160 A/200 A) ⋅ I
Nsec
maximum number of warm starts
difference between the allowed
number of cold starts and warm
starts
extension factor for the time
constant of the rotor temperature
equilibrium replica at motor stop
extension factor for the time
constant of the rotor temperature
equilibrium replica at running
motor
(I > current threshold of CB
Motor
50-1 pickup)
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