DualDC - HV bus over voltage or under voltage fault

Hoping to get some direction with this problem

I have my VSD-XE setup on my test bench, servo tuned (servo shaft not mechanically connected to anything) and have USBCNC controller configured and connected to the drive. (i have only 1 servo connected to the drive for testing)

I am getting the "HV bus over voltage or under voltage fault" when i run the servo at speeds greater then 205 ipm.

I can't pinpoint exactly when the fault occurs, it seems like sometime it faults when the move is commanded and other times when the servo is coming to a stop after the move.

Any feed below 205 ipm runs great, 20 or 30 lines of code, changing direction and speed. But anything over the 205 and i start getting faults.

The dualDC manual says this:

Q: I'm getting overvoltage or undervoltage faults
Measured HV bus voltage is not within user specified fault limits. Most common reasons include:

●

Regenerative supply pumping. During motor braking supply voltage tends to increase as motor

acts as generator. To verify this, attach voltmeter to PSU to check voltage during fault. To prevent

this, use regenerative resistor (see chapter Error: Reference source not found Error: Reference

source not found).

● Supply voltage gone below lower voltage limit. This may be caused by undersized power supply.

The regular manual says this:

I'm getting overvoltage or undervoltage faults
Measured HV bus voltage is not within user specified fault limits. Most common reasons include:
● Regenerative supply pumping. During motor braking supply voltage tends to increase as motor
acts as generator. To verify this, attach voltmeter to PSU to check voltage during fault. To prevent
this, use regenerative resistor (see chapter 8.6 Regenerative resistor).
● Supply voltage gone below lower voltage limit. This may be caused by undersized power supply.

I have DCtool current settings maxed out.

I monitored HV voltage during faults with my multimeter in min/max mode. Never saw a voltage over 165vdc. I saw the same voltage when the servo came to a stop with no fault.

My power supply is the SPS-600-126. From what I understand this is more then adequate and definitely not suffering from under voltage.

Since I can not use a breaking resistor in DualDC mode, what is my next step?

It is most likely overvoltage fault due to regenerative energy. 165VDC is very close to overvotlage fault and SPS600 gives 126VDC so there has been generated voltage to bump it to 165VDC (and sometimes higher which causes the fault).

The solutions are:
* Something that draws excessive voltage from HV bus: either a VSD drive in single axis mode with braking resistor (i.e. if you have 3 axis you can set one in single axis mode) or some external circuit with same function
* Reduce deceleration speed so generated voltage stays lower

Thankyou for your reply