Regenerative Resistors


When installing Regeneration Resistors care must be taken as the resistor absorbs the regeneration power, and it is possible to generate high temperatures above 100°C.

Provide adequate cooling and use appropriate high temperature wires and ensure there is adequate space between regeneration resistor and other materials.  Install as far away from other components as possible to avoid electrical noise and heat damage.

For Teco:

  • Most users will use the internal resistor; leave the jumper between PC-P1
  • Persistent AL02 errors may require the addition of an external resistor to the servo drive
  • For an external resistor, remove PC-P1 jumper and wire between P-PC
    • Set Cn012 to the wattage of the external resistor (i.e. - Set Cn012 to 500 for a 500W resistor)

For Yaskawa:

  • If the drive has an internal resistor, there will be a jumper between B2-B3 terminals
  • Some servopack models do not have an internal resistor so an external regenerative resistor is required
  • For an external resistor, remove B2-B3 if present and wire between B1-B2
    • Set Pn600 with the Regenerative Resistor Capacity
    • A.320 alarm is because the resistor wattage has not been programmed or not set correctly
    • See pg. 3-38 thru 3-40 for further details (not sure what page that is referring to. Found it starting 3-41 in our online manual).
  • SETTING PN600:

Be sure to set the regenerative resistor capacity (Pn600) to a value that is in accordance with the allowable
capacity of the actual external regenerative resistor being used.


1. If Pn600 is not set to the optimum value, alarm A.320 will occur.
2. When set to the factory setting (Pn600 = 0), the SERVOPACK’s built-in resistor or Yaskawa’s regenerative resistor
unit has been used.

The setting will vary with the cooling method of external regenerative resistor:
• For natural convection cooling: Set the value to a maximum 20% of the actually installed regenerative
resistor capacity (W).
• For forced convection cooling: Set the value to a maximum 50% of the actually installed regenerative
resistor capacity (W).

Example: Set 20 W (100 W × 20%) for the 100-W external regenerative resistor with natural convection
cooling method:
Pn600 = 2 (unit: 10 W)


See attached PDF for more information.



regen resistor, Teco, Yaskawa, A.320, AL02


Keywords: 10978

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