Chapter 11 Selection
11-9
(1) Horizontal axis load torque
When operations ① to ⑧ are for a horizontal axis, calculate so that the following torques are
required in each period.
Table 11-6 Load torques of horizontal axes
Period Load torque calculation method Explanation
①
(Amount of acceleration torque) +
(Kinetic friction torque)
Normally the acceleration/deceleration time constant is
calculated so this torque is 80% of the maximum torque of the
motor.
②
(Kinetic friction torque)
③
(Amount of deceleration torque) +
(Kinetic friction torque)
The signs for the amount of acceleration torque and amount of
deceleration torque are reversed when the absolute value is
the same value.
④
(Static friction torque)
Calculate so that the static friction torque is always required
during a stop.
⑤
− (Amount of acceleration torque) −
(Kinetic friction torque)
The signs are reversed with period ① when the kinetic friction
does not change according to movement direction.
⑥
− (Kinetic friction torque)
The signs are reversed with period ② when the kinetic friction
does not change according to movement direction.
⑦
− (Amount of deceleration torque) −
(Kinetic friction torque)
The signs are reversed with period ③ when the kinetic friction
does not change according to movement direction.
⑧
− (Static friction torque)
Calculate so that the static friction torque is always required
during a stop.
(2) Unbalance axis load torque
When operations ① to ⑧ are for an unbalance axis, calculate so that the following torques are
required in each period. Note that the forward speed shall be an upward movement.
Table 11-7 Load torques of unbalance axes
Period Load torque calculation method Explanation
①
(Amount of acceleration torque) +
(Kinetic friction torque) + (Unbalance
torque)
Normally the acceleration/deceleration time constant is
calculated so this torque is 80% of the maximum torque of the
motor.
②
(Kinetic friction torque) + (Unbalance
torque)
③
(Amount of deceleration torque) +
(Kinetic friction torque) + (Unbalance
torque)
The signs for the amount of acceleration torque and amount of
deceleration torque are reversed when the absolute value is
the same value.
④
(Static friction torque) + (Unbalance
torque)
The holding torque during a stop becomes fairly large.
(Upward stop)
⑤
− (Amount of acceleration torque) −
(Kinetic friction torque) + (Unbalance
torque)
⑥
− (Kinetic friction torque) +
(Unbalance torque)
The generated torque may be in the reverse of the movement
direction, depending on the size of the unbalance torque.
⑦
− (Amount of deceleration torque) −
(Kinetic friction torque) + (Unbalance
torque)
⑧
− (Static friction torque) + (Unbalance
torque)
The holding torque becomes smaller than the upward stop.
(Downward stop)
POINT
During a stop, the static friction torque may constantly be applied. The static
friction torque and unbalance torque may particularly become larger during an
unbalance upward stop, and the torque during a stop may become extremely
large. Therefore, caution is advised.
To Next Page
Loading...
