Delta Electronics none Manual De Usuario

Chapter 6  Control Modes of Operation|ASDA-AB Series 

Revision March 2008, Doc. Name: 2007PDD23000011 

 

 

6-37 

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When using external regenerative resistor, connect it to P and C, and make sure the circuit between P 

and D is open. We recommend the users should use the external regenerative resistor that the 

resistance value following the above table (Built-in Regenerative Resistor Specifications). 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. 
 

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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. 

Servo Drive 

(kW) 

Rotor Inertia 

J (kg. m

2

) 

Regenerative power from empty load 

3000r/min to stop Eo (joule) 

Max. regenerative power 

of capacitance Ec(joule)

0.1 0.03E-4 

0.15 

3 

0.2 0.18E-4 

0.89 

4 

0.4 0.34E-4 

1.68 

8 

0.75 1.08E-4 

5.34 

14 

1.0 2.60E-4 

12.86 

18 

1.5 3.60E-4 

17.80 

18 

2.0 4.70E-4 

23.24 

21 

Eo = J x wr

2

/182 (joule)  

 

, Wr : r/min 

If the load inertia is N ×  motor inertia, the regenerative power will be (N+1) x  E0 when servo motor 

brakes from 3000r/min to 0. Then, the regenerative resistor can dissipate: (N+1) x   E0 - Ec (joule). If the 

time of repeat operation cycle is T sec, then the regenerative power = 2 x   ((N+1) x   E0 - Ec) / T. The 

calculating procedure is as follows: 

Step 

Procedure 

Equation and Setting Method 

1 

Set the capacity of regenerative 
resistor to the maximum 

Change the value of P1-53 to maximum 

2 

Set the operation cycle T 

Input by the users 

3 

Set motor speed wr 

Input by the users or read via P0-02 Drive State Display

4 

Set load/motor inertia ratio N 

Input by the users or read via P0-02 Drive State Display

5 

Calculate the max. regenerative 
power Eo 

Eo = J x  wr

2

/182 

6 

Set the regenerative power Ec that 
can be absorbed 

Refer to the table above 

7 

Calculate the required 
regenerative power capacity 

2 x (N+1) x  Eo－Ec）/ T