BECKHOFF AM8000 - Manual (Page 36)

10 Technical data Drive Technology
36 Version: 2.4 AM8000 and AM8500
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 M
0
[Nm]
The standstill torque can be maintained indefinitely at a speed n<100 rpm and rated ambient conditions.
Rated torque M
n
[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).
Standstill current I
0rms
[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) I
0max
[A]
The peak current (effective sinusoidal value) is approximately equivalent to 5-times the rated standstill current
(3-times at AM806x, AM807x and AM856x). The configured peak current of the servo drive used must be
smaller.
Torque constant K
Trms
[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 K
T
Voltage constant K
Erms
[mVmin]
The voltage constant defines the induced motor EMF, as an effective sinusoidal value between two terminals,
at 20 °C 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:
J x
cm
m
x
s x M
x
S t
b 2 4
2
10 60
2 3000
] [
0
π
= with M
0
in Nm and J in kgcm 2
Thermal time constant t
TH
[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 t
BRH
[ms] / Application delay time t
BRL
[ms] of the brake
These constants define the response times of the holding brake when operated with the rated voltage from the
servo drive.