Delta Electronics ASDA-A2 Series User Manual page 33

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When the regenerative power exceeds the processing capacity of the servo drive, install
an external regenerative resistor. Please pay close attention to the following notes when
using a regenerative resistor.
1. Make sure the settings of resistance (parameter P1-52) and capacity (parameter P1-53)
are set correctly.
2. When installing an external regenerative resistor, make sure that its resistance value
is the same as the resistance of the built-in regenerative resistor. If combining
multiple small-capacity regenerative resistors in parallel to increase the regenerative
resistor capacity, make sure that the resistance value of the regenerative resistor
complies with the specifications listed in the table above.
3. In general, when the amount of regenerative power (average value) that can be
processed is used at or below the rated load ratio, the resistance temperature will
increase to 120°C or higher (when the regeneration occurs continuously). For safety
reasons, forced air cooling is a good way to reduce the temperature of the
regenerative resistors. We also recommend using regenerative resistors with thermal
switches. As for the load characteristics of the regenerative resistors, please check
with the manufacturer.
 External Regenerative Resistor
When using an external regenerative resistor, connect it to P
circuit between P
with resistance values that follow the table above (Specifications of Built-in Regenerative
Resistors). We ignore the dissipative power of IGBT (Insulated Gate Bipolar Transistor) in
order to let the users easily calculate the capacity of regenerative resistor. In the following
sections, we will describe Regenerative Power Calculation Method and Simple Calculation
Method for calculating the regenerative power capacity of external regenerative resistors.
 Regenerative Power Calculation Method
(1) Without Load
When there is no external load torque, if the servo motor repeats operation, the returned
regenerative power generated when braking will transmitted into the capacitance of DC
bus. After the capacitance voltage exceeds some high value, regenerative resistor can
dissipate the remained regenerative power. Use the table and procedure described below
to calculate the regenerative power.
2-14
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and D is open. We recommend using external regenerative resistors
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Chapter 2 Installation and Storage
and C, and make sure the
Revision January 2011
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