Motion Control and Motor Drives

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Frequency limit of servo motor

Hi Everyone,


I am facing a problem in my project regarding servo drive. My project is to check rotational durability of a mechanical shaft.

For this i am using 2 servo motors of 5 KW each, one is traveling in torque mode while other is in position mode.

I have to check it at a particular frequency range which is upto 0.15 Hz at a particular angle & Torque according to customer specifications.

My programme is performing well upto frequency 0.08 Hz. & at specific torque & angle setting. But when i increase this frequency. Then servo drive comes in fault showing Err 12 which means over voltage protection. But i could not rectify this problem.


Kindly suggest me on giving high frequeny which factors affecting this servo drive.


Thanks & Regards,

Vipin Ahuja

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Message 1 of 9

Since I am not sure what drive you have, this will be a guess.  Typically an overvoltage alarm arises because the motor is becoming a generator, and the DC bus voltage rises to a level that may damage the circuits and the drive shuts down to protect itself.  If your drive doesn't have any kind of braking resistors, then one needs to be added.  If it has one, then a larger one is needed.  You need to be sure you add the resistors properly, and a chopper might have to be added if your drive doesn't have one.  What drive are you using?

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Message 2 of 9

Thanks for your reply.

I am using Panasonic Minas A4 series drive & servo motor is of 5KW. Can you tell me How much value of this resistor i have to add as a breaking resistor & i dont have knowledge about chopper which you r saying in your reply.

Can you elaborate?


Thanks & Regards,

Vipin Ahuja

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Message 3 of 9

All of that information should be in the manual for the drive.

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Message 4 of 9

No, Exact value of Breaking resisitor is not given in manual, i have already checked it.

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Message 5 of 9
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Message 6 of 9

Thanks for your kind effort, but my problem still persisting.

Actually contact no. which you have given in pdf reference are not working.

Again i am giving data that i m using MFMD Model, 5KW, Minas A4 series panasonic servo drive.

I want how much ohm resistor i have to add.


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Message 7 of 9

I suggest you contact Panasonic to discuss the topic:


Regeneration discharging function

Discharges the regenerative energy with resistor, which energy is

generated while stopping the load with large moment of inertia, or

use in up-down operation, and is returned to the driver from the


No regeneration discharge resistor is built-in to Frame A driver

(MADDT1105 type.), Frame B driver (MBDDT2210 type.) and

Frame G driver (MGDDTC3B4 type.) and we recommend you to

connect optional regenerative resistor.

Regenerative resistor is built-in to Frame C to F drivers, however,

connection of the optional regenerative resistor bring you further

regenerative capability.



"It’s the questions that drive us.”
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Message 8 of 9

Let me understand:

You are using two motors (connected by the same shaft), one as motor and the other one as brake?

When the error occours, measure the DC link voltage with a multimeter and check the limits. Measure the brake resistor (if any) and increase its size to dissipate more heat (current)

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Message 9 of 9