Harmonic Drive MMA Series, Manual, Page: 40 / 62

2-3 Examining the operating status
2-7
Se
lec
tion gui
de
lin
es
2
Appe
(5) The * mark in the figure on the right shows the points of operation determined by the effective
torque and average rotational speed calculated above, plotted on the graph of operable range
of MMAB09, exceeding the continuous motion range. The conclusion is that this motor cannot
be operated continuously under these conditions. Accordingly,
◆
the operation pattern
◆
load (possible reduction)
◆
motor model No.
etc., must be reevaluated.
The following formula is a modified version
of the formula for effective torque. By
applying the value of allowable continuous
torque to T
m
in this formula, the allowable
cycle time can be calculated.
Apply the following:
T
a
= 2.30 [N
･
m]
T
r
= 0 [N
･
m]
T
d
= 2.53 [N
･
m]
T
m
= 0.80 [N
･
m]
t
a
= 0.087 [s]
t
r
= 0.069 [s]
t
d
= 0.075 [s]
Then, the following equation is obtained:
t = (2.30
2
× 0.087 + 2.53
2
× 0.075) / 0.80
2
= 1.46 [s]
Based on the result, setting the cycle time to 1.5 seconds or more to provide a longer stop time
gives T
m
= 0.80 [N
･
m] or less, thereby permitting continuous operation within the rated torque.

The aforementioned continuous motion range represents an allowable range where the
motor installed on a specified aluminum radiation plate is operated under natural air
cooling. If the radiation area of the mounting member is small or heat conduction of the
material is poor, adjust the operating conditions to keep the rise in the motor's ambient
temperature to 40 K or less as a guide.
Operable range of MMAB09
Tor
que [
N
･
m]
Motion range during
acceleration and deceleration
Continuous motion range
Aluminum radiation plate: 350
×
350
×
18 [mm]
Rotation speed [r/min]
*
2
m
d
2
d r
2
r a
2
a
T
t T t T t T
t
× + × + ×
=