Assembly Instruction
Technical Terms
Torque Motor
TM-Komponenten-04-0-EN-2108-MA
Page 78 of 84
10
Technical Terms
Back EMF constant (line-to-line):
K
v
�
V
rms
rad
/
s
�
The back EMF constant,
K
v
, is the ratio of the back EMF voltage (
V
rms
) to the motor rotational speed
(
rad/s
)
when the magnet is at 25
℃
. It is created at the movement of the coil in the magnetic field of
permanent magnets.
Continuous current:
I
c
/I
cw
(A
rms
)
The continuous current,
I
c
, is the current that can be continuously supplied to the motor coils at the
ambient temperature 25
℃
, and the final temperature of coil can’t exceed 120
℃
(130
℃
for
□
M-2 series).
Under this condition, the motor reaches the rating continuous torque
T
c
;
in relation with the continuous
current and coil temperature, torque motor will respond to
I
c
for air cooling and
I
cw
for water cooling
Continuous torque:
T
c
/T
cw
(Nm)
The continuous torque,
T
c
, is the maximum torque the motor is able to generate continuously at the
ambient temperature 25
℃
and the final temperature of coil can’t exceed 120
℃
(130
℃
for
□
M-2 series).
This continuous torque correspond to
I
c
/I
cw
supplied to the motor; in relation with continuous current and
coil temperature, torque motor will respond to
T
c
for air cooling and
T
cw
for water cooling.
Inductance (line-to-line):
L
(mH)
Inductance is defined as inductance measured between lines when the motor operates at the coil
temperature 25
℃
.
Resistance at 25
℃
(line-to-line):
R
25
(
Ω
)
Resistance is defined as resistance measured between lines when the motor operates at the coil
temperature 25
℃
.
Motor constant:
K
m
�
Nm
√W
�
The motor constant,
K
m
, is defined as the ratio of square root of motor output torque to consumption
power when the coils and magnets are at 25 °C. The larger motor constant represents the lower power loss
when the motor outputs at the specific torque.
Number of poles: 2p
2p represents the number of poles of the rotor, where p is the number of poles pair.
Peak current:
I
p
(A
rms
)
The peak current,
I
p
, is the current corresponding to torque output of the motor, and the motor temperature
reached by current can’t demagnetize magnet. Generally speaking, peak current can be granted to supply 1
second when the motor is operating in the normal condition and the input current phase is balanced. And
then the motor needs to rest for at least 6 seconds after it reaches the normal temperature to supply peak
current. (For more accurate time, please contact HIWIN).
Peak torque:
T
p
(Nm)
The peak torque,
T
p
, is the maximum torque that the motor outputs less than 1 second. Peak current
corresponding to the torque cannot demagnetize magnet.
Rotor inertia:
J
(kgm
2
)
The rotor inertia,
𝐊𝐊
, is the rotary component resists any changes in its state of motion, including changes to
its speed and direction. It is related to the shape and mass.
Stall current:
I
s
/I
sw
(A
rms
)
The stall current,
I
s
, is the upper limit of current when the motor is at 25 °C and in the stall condition.
Depending on the heat dissipation, torque motor will correspond to
I
s
for air cooling and
I
sw
for water
cooling.
