BECKHOFF AM8100 - Manual (Page 27)

Technical data
10 Technical data
All data, excluding the voltage constant, valid for 40 °C ambient temperature and 100 K overtemperature of
the winding.
The data can have a tolerance of +/­ 10%.
If a gear unit is attached the power may be reduced by up to 20%. This loss in performance has thermal
reasons, since a gear unit that is subject to warming is installed at the motor flange intended for heat
Dissipation.
Term definitions
Standstill torque M0 [Nm]
The standstill torque can be maintained indefinitely at a speed n<100 rpm and rated ambient conditions.
Rated torque Mn [Nm]
The rated torque is produced when the motor is drawing the rated current at the rated speed.
The rated torque can be produced indefinitely at the rated speed in continuous operation (S1).
Nominal speed nn [rpm]
At the nominal speed motor output corresponds to the rated torque and the rated output. The nominal speed
depends on the supply voltage. The example below refers to supply voltages of 24 and 48 VDC. The supply
voltages are specified without tolerances.
Standstill current I0rms [A]
The standstill current is the effective sinusoidal current which the motor draws at n<100 rpm to produce the
standstill torque.
Peak current (pulse current) I0max [A]
The peak current (effective sinusoidal value) is approximately equivalent to 5­times the rated standstill
current. The configured peak current of the servo terminal used must be smaller.
Torque constant KTrms [Nm/A]
The torque constant defines how much torque in Nm is produced by the motor with standstill current. The
relationship is M
0
= I
0
x KT
Voltage constant KErms [mVmin]
The voltage constant defines the induced motor EMF at 20 °C, as an effective sinusoidal value between two
terminals, per 1000 rpm.
Rotor moment of inertia J [kgcm²]
The constant J is a measure of the acceleration capability of the motor. For instance, at I
0
the acceleration
time t
b
from 0 to 3000 rpm is given as:
with M
0
in Nm and J in kgcm 2
Thermal time constant tTH [min]
The constant t
TH
defines the time for the cold motor, under a load of I
0
to heat up to an overtemperature of
0.63 x 100 Kelvin.
This temperature rise happens in a much shorter time when the motor is loaded with the peak current.
Release delay time tBRH [ms] / Application delay time tBRL [ms] of the brake
These constants define the response times of the stopping brake when operated with the rated voltage at the
servo terminal.
Synchronous servomotor AM8100 27 Version 1.1