Siemens S120 configurationmanual Physical constants

Technical data and characteristics 14.1 Explanations of the formula abbreviations

nMAX,MMAX

nMAX,0

M0

Maximum speed up to which the motor can deliver the maximum torque MMAX. No-load speed; max. speed without load.

Torque for speed n = 1 [rpm] at which the load and power loss are still evenly distributed across all three motor lines.

I0	Current (rms value) of the motor at torque M0 and speed n = 1 [rpm].
M0*	Thermal static torque when the current is unevenly distributed across the three
	motor lines. An uneven current load occurs in the following operating modes:
	∙ Standstill
	∙ Operation with short cyclic rotations (< 1 pole pitch)
	∙ For n << 1 [rpm]
	Since the saturation effect can be disregarded for the rated current, the
	following applies (approximately):
I0*	Thermal stall current (rms value) of the motor at M0*. The following applies:

Physical constants

kT,20

kE

kM,20

tTH

Motor torque constants at a rotor temperature of 20 °C (refers to the lower linear range of the torque–current characteristic).

Voltage constants for calculating the mutually induced line-to-line voltage.

Motor constant at a winding temperature of T = 20 °C.

The motor constant kM(T) may be calculated for other temperatures: kM(T) = kM,20 ∙ [1 + α(T – 20 °C)]

with temperature coefficient α = − 0.001 1/K for magnets kM(T) = kM,20 ∙ [1 - 0.001 ∙ (T – 20 °C)]

Thermal time constant of the motor winding. This is derived from the temperature characteristic in the winding with a sudden load and constant current. See diagram below. When the time tTH has elapsed, the motor winding reaches approximately 63% of its final temperature TGRENZ if thermal protection was not active prior to this.

1FW6 Built-in torque motors	177
Configuration Manual, 05/2009, 6SN1197-0AE00-0BP3