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Regenerative Resistor
When the servo motor operates in generator mode, power is returned to the servo drive side. This is
called regenerative power. The regenerative power is absorbed by charging the smoothing capacitor,
but when the capacitor’s charging limit is exceeded, the regenerative power needs to be reduced by the
regenerative resistor.
The servomotor is driven in regeneration (generator) mode in the following conditions:
From decelerating to stop for acceleration/deceleration operation.
Move down on the vertical axis.
The external load drives the motor running
Servo drive
Regenerative resistor connection terminals
DS3-2□P□-PQA
DS3-4□P□-PQA
DS3E-2□P□-PFA
DS3E-4□P□-PFA
DS3L-2□P□-PFA
DS3L-4□P□-PFA
DS3-2□P□-PTA
DS3-4□P□-PTA
for internal regenerative resistor: short P+ and D, disconnect P+ and C,
P0-24=0.
for external regenerative resistor: connect resistor between P+ and C,
disconnect P+ and D, P0-24=1, P0-25=power value, P0-26=resistor value.
Parameter Signal name
Setting
Meaning
Effective Modify
P0-24
Choose
regenerative
resistor
0
Use internal regenerative resistor
At once
Servo OFF
1
Use external regenerative resistor
(resistor type please refer to the
following table)
Parameter Signal name
Setting
Unit Effective
P0-25
Discharge
resistor power
1. self-cooling mode (natural convection cooling):
below 20% of regenerative resistor capacity (W)
2. forced air cooling: below 50% of regenerative
resistor capacity (W)
W
At once
P0-26
Discharge
resistor value
Resistor value
Ω
At once
The type of regenerative resistor:
Servo drive
Min resistor
(cannot smaller than
this value)
External regenerative
resistor (recommend
value)
External regenerative
resistor (recommend
power)
DS3-20P2-PQA
DS3E-20P2-PFA
DS3L-20P2-PFA
DS3-20P2-PTA
50Ω
50Ω—100Ω
Above 200W
DS3-20P4-PQA
DS3E-20P4-PFA
DS3L-20P4-PFA
DS3-20P4-PTA
40Ω
40Ω—100Ω
Above 500W
DS3-20P7-PQA
DS3E-20P7-PFA
DS3L-20P7-PFA
DS3-20P7-PTA
40Ω
40Ω—100Ω
Above 500W
DS3-21P5-PQA
DS3E-21P5-PFA
DS3L-21P5-PFA
DS3-21P5-PTA
25Ω
25Ω—50Ω
Above 1000W
DS3-22P3-PQA
DS3E-22P3-PFA
DS3L-22P3-PFA
25Ω
25Ω—50Ω
Above 1000W