Technical data

Siemens SIP · 2008
12 Motor Protection / 7SK80
12
Technical Data page 7
Technical data
Restart inhibit for motors (ANSI 66)
Setting ranges
Motor starting current relative
to rated motor current
I
MOTOR START
/I
Motor Nom
Rated motor current I
Motor Nom
Max. permissible starting time
T
Start Max.
Equilibrium time T
Equal
Minimum inhibit time
T
MIN. INHIBIT TIME
Max. permissible number of
warm startups n
WARM
Difference between cold and
warm startups n
COLD
–n
WARM
Extension of time constant at
stop k
τ at STOP
Extension of time constant at
running k
τ at RUNNING
1.1to10(instepsof0.1)
1to6A
1)
(in steps of 0.01 A)
1to320s(instepsof1s)
0 min to 320 min (in steps of 0.1 min)
0.2 min to 120 min (in steps of 0.1 min)
1to4(instepsof1)
1to2(instepsof1)
0.2 to 100 (in steps of 0.1)
0.2 to 100 (in steps of 0.1)
Restart threshold
Θ
RESTART
STARTUP
Motor Nom R
n
k
e
cold
=
⋅
⎛
⎝
⎜
⎞
⎠
⎟
⋅
−
I
I
2
1
1–
()⋅
⎛
⎝
⎜
⎜
⎞
⎠
⎟
⎟
T
START max
R
τ
Where: Θ
RESTART
= Temperature limit
below which restarting
is possible
k
R
= k-factor for the rotor
I
STARTUP
= Startup current
I
MOT Nom
= Motor rated current
T
START max
= Max. startup time
τ
R
= Thermal rotor time
constant
n
cold
=Max.numberofcold
starts
Undercurrent monitoring (ANSI 37)
Signal from the operational
measured values
Predefined with programmable logic
Temperature detection
Temperature detection through internal module (only 7SK805/7SK806)
Number of temperature detectors
Measuring method
Installation identification
5
Pt 100 Ω or Ni 100 Ω or Ni 120 Ω
3-wire connection, shielded cable
“Oil” or “Ambient” or “Stator” or
“Bearing” or “Other”
Temperature detection through external RTD boxes
Connectable RTD-boxes
Number of temperature detectors
per RTD-box
Measuring method
Mounting identification
1or2
Max. 6
Pt 100 Ω or Ni 100 Ω or Ni 120 Ω
Selectable 2- or 3-phase connection,
shielded cable
“Oil” or “Ambient” or “Stator” or
“Bearing” or “Other”
Thresholds for indications
For each measuring detector
Stage 1
Stage 2
–50 °C to 250 °C (in steps of 1 °C)
–58 °F to 482 °F or ∞ (no indication)
–50 °C to 250 °C (in steps of 1 °C)
–58 °F to 482 °F or ∞ (no indication)
Thermal overload protection (ANSI 49)
Setting ranges
Factor k 0.1 to 4 (in steps of 0.01)
Time constant
Thermal alarm Θ
Alarm
/Θ
Trip
1 to 999.9 min (in steps of 0.1 min)
50 to 100 % of the trip excessive
temperature (in steps of 1 %)
Current warning stage I
Alarm
0.5 to 20 A (in steps of 0.01 A)
Extension factor when stopped
k
τ
factor
1 to 10 with reference to the time
constant with the machine running
(in steps of 0.1)
Rated overtemperature (for I
nom
) 40 to 200 °C (in steps of 1 °C)
Tripping characteristic
For (I/k · I
nom
) ≤ 8
()( )
()
t =⋅
⋅− ⋅
⋅−
τ
th
nom
2
pre nom
2
nom
2
kk
k
ln
//II I I
II/ 1
t = Tripping time in minutes
τ
th
= Temperature-rise time
constant
I = Actual load current
I
pre
= Preload current
k = Setting factor acc. to
IEC 60255-8
I
nom
= Rated (nominal) current of
the protected object
Dropout ratios
Θ/Θ
Trip
Θ/Θ
Alarm
I/I
Alarm
Drops out with Θ
Alarm
Approx. 0.99
Approx. 0.97
Tolerances
With reference to k · I
nom
With reference to tripping time
3%or75mA
1)
2 % class acc. to IEC 60255-8
3%or1sforI/(k · I
nom
) > 1.25
3 % class acc. to IEC 60255-8
(Sensitive) ground-fault protection (ANSI 64, 50Ns, 51Ns, 67Ns)
Displacement voltage element for all types of ground fault (ANSI 64)
Setting ranges
Displacement voltage (measured)
Displacement voltage (calculated)
Delay time T
Delay pickup
Additional trip delay T
VDelay
V
0
> 1.8 to 200 V (in steps of 0.1 V)
3V
0
>10to225V(instepsof0.1V)
0.04 to 320 s or ∞ (in steps of 0.01 s)
0.1 to 40,000 s or ∞ (in steps of 0.01 s)
Operating time Approx. 50 ms
Dropout ratio 0.95 or (pickup value –0.6 V)
Tolerances (measurement)
Pickup threshold V
0
(measured)
Pickup threshold 3V
0
(calculated)
Delay times
3 % of setting value or 0.3 V
3 % of setting value or 3 V
1%ofsettingvalueor10ms
Phase detection for ground fault in an ungrounded system
Measuring principle Voltage measurement
(phase-to-ground)
Setting ranges
V
ph min
(ground-fault phase) 10 to 100 V (in steps of 1 V)
V
ph max
(healthy phases) 10 to 100 V (in steps of 1 V)
Tolerance
Measurement tolerance
acc. to VDE 0435, Part 303
3 % of setting value or 1 V