
3.SELECTING A MOTOR SPECIFICATIONS FOR THE βiS SERIES B-65302EN/01
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Calculating the percentage duty cycle with the maximum cutting torque
Maximum cutting torque (Tms)
To rq ue
Time
If the load torque (T
ms
) is greater than the product of the motor stall
torque (T
s
) and thermal efficiency (α), calculate the root-mean-square
value of torque applied in a single cutting cycle. Specify t
ON
and t
OFF
so that the value does not exceed the product of the motor stall torque
(T
s
) and thermal efficiency (α). Then, calculate the percentage duty
cycle with the maximum cutting torque as shown below.
Percentage duty cycle with the maximum cutting torque (Tms)
=
100[%]×
+
offon
on
tt
t
[Example of calculation for condition 6-2]
Percentage duty cycle and ON time with the maximum cutting force
Example)
Assume that T
ms
is 15 [N⋅m] (T
m
is 1.4 [N⋅m]).
][9.9
4.115
22
mN
tt
tt
offon
offon
⋅<
+
+
(90% of the rated torque of the
β12/3000is)
Therefore,
76.0<
off
on
t
t
The above ratio of the non-cutting time to the cutting time is
required. The percentage duty cycle is calculated as follows:
43.0%100 =×
+
offon
on
tt
t
Limitations on ON time
The period during which continuous operation under an overload is
allowed is also restricted by the OVC alarm level and overload duty
cycle characteristics. Refer to Subsec.3.4.1 for details