Siemens SINAMICS S120 Configuration Manual page 50

Electrical data
4.4 Definitions
Voltage constant k (value at 20 °C rotor temperature)
E
Value of the induced motor voltage at a speed of 1000 RPM and a rotor temperature
of 20 °C.
The phase-to-phase RMS motor terminal voltage is specified for 1FK7 motors.
Winding resistance R
The resistance of a phase at a winding temperature of 20 °C is specified. The winding has
a star circuit configuration.
Cyclic inductance L
D
The cyclic inductance is the sum of the air gap inductance and leakage inductance relative
to the single-strand equivalent circuit diagram. It consists of the self-inductance of a phase
and the coupled inductance to other phases.
Electrical time constant T
Quotient obtained from the rotating field inductance and winding resistance. T
Mechanical time constant T
The mechanical time constant is obtained from the tangent at a theoretical ramp-up function
through the origin.
T
mech
J
mot
R
ph.
k
T
Thermal time constant T
Defines the increase in the motor frame temperature when the motor load is suddenly
increased (step function) to the permissible S1 torque. The motor has reached 63%
of its final temperature after T
Shaft torsional stiffness c
This specifies the shaft torsional stiffness from the center of the rotor laminated core to
the center of the shaft end.
Rated converter current I
RMS converter output current (per phase) that can be supplied on a continuing basis by
the recommended motor module The recommended motor module is selected such
that I
50
at 20 °C winding temperature
ph
el
mech
= 3 ∙ R ∙ J /k [s]
T 2
ph mot
= Servomotor moment of inertia [kgm
= Phase resistance of the stator winding [Ohm]
= Torque constant [Nm/A]
th
T
N Inv
is greater than the stall current I
N Inv
]
2
.
th
.
0 (100 K)
Configuration Manual, (PFK7S), Edition 12.2006, 6SN1197-0AD16-0BP1
= L /R
el D ph
Synchronous Motors 1FK7