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Motor Data Legend | 07 Nov 2013 | |

# Motor Data Legend

Symbol Dimension English Description
M0 Nm Standstill torque The standstill torque can be maintained indefinitely at a speed n<100 rpm and rated ambient conditions.
Mn Nm Rated torque 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).
I0rms A Standstill current The standstill current is the effective sinusoidal current which the motor draws at n<100 rpm to produce the standstill torque.
I0max A Peak current The peak current (effective sinusoidal value) is approximately equivalent to 3-, 4-, or 5-times the rated current depending on the motor type and size. The actual value is determined by the peak current of the servo amplifier which is used.
In A Rated current
nn 1/min Rated speed
ngrenz 1/min allowed limit speed
KTrms Nm/A Current constant The torque constant defines how much torque in Nm is produced by the motor with 1A r.m.s. current. The relationship is M=I x KT (up to I = 2 x I0)
Zusammenhang KT/KE:
KE mVmin Voltage constant The voltage constant defines the induced motor EMF, as an effective sinusoidal value between two terminals, per 1000 rpm
Pn kW Rated power
Un V DC Bus Link voltage
UN V Mains rated voltage
pmot - Motor pole number
pres - Resolver pole number
R20 Ohm Winding resistance measured Phase- Phase at 20°C
L mH Winding inductance measured Phase- Phase
J kgcm² Rotor moment of inertia The constant J is a measure of the acceleration capability of the motor. For instance, at I0 the acceleration time t from 0 to 3000 rpm is given as::
 3000 x 2π m² t(s)= x x J M0 x 60s 104 x cm²

with M0 in Nm and J in kgcm²

MR Nm Static friction torque
FR N Radial load permitted shaft end at rated speed
FA N Axial load permitted shaft end at rated speed
tth min Thermal time constant The constant tth defines the time for the cold motor, under a load of I0, to heat up to an overtemperature of 0.63 x 105 Kelvin. This temperature rise happens in a much shorter time when the motor is loaded with the rated current.
tbrh ms   These constant defines the "open" response time of the holding brake when operated with the rated voltage from the servo amplifier.
tbrl ms   These constant defines the "close" response time of the holding brake when operated with the rated voltage from the servo amplifier.

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