Chapter 2 Installation
ASDA-A2R Series
2-14
Revision December, 2014
Steps
Item
Calculation and Setting Method
5
Calculate the maximum
regenerative energy E
E = 0.5 mv2
6
Set the absorbable regenerative
energy Ec
Refer to the above table
7
Calculate the needful capacitance
of regenerative resistor
2 × (E – Ec) / T
Take 400W as the example, the cycle of back and forth operation is T = 0.4sec,
assume that the maximum speed is 2m/s and the total weight of movable section and
load is 7kg, the needful power of regenerative resistor is 2 × (0.5*7*2
2
－
8.42) / 0.4 =
27.9 W. If it is smaller than the built-in capacity of regenerative resistor, the built-in
60W regenerative resistor will do. Generally speaking, when the need of movable
section and the external load inertia is not much, the built-in regenerative is enough.
The diagram below describes the actual operation. The smaller power of the
regenerative resistor it is, the more energy it accumulates and the higher temperature
it will be. When the temperature is higher than a specific value, ALE05 occurs.
(b) When the external load torque exists, the motor is in reverse rotation.
Usually, the motor is in forward rotation, which means the force direction of the motor
is the same as the moving direction.
However, in some applications, the direction of
force is different from the moving direction.
In this situation, the motor is in reverse
rotation. The external energy goes into the servo drive through the motor. The
diagram below is one of the examples. When the motor is in constant speed, it is
positive force in most of the time and a huge amount of energy rapidly transmits to
regenerative resistor.
馬 達 轉 速
外 部 負 載 扭 矩
馬 達 輸 出 扭 矩
馬 達 輸 出 負 功
正 功
負 功
正功
Negative force: TL × Wr TL: external force
推力
推力
速度
Motor speed
External force
Motor output force
Positive
force
Positive
force
Negative force
Negative force
