Electromagnetic interference VFD MX2 Omron

Hi everyone I have a problem with vfd 3G3-MX2 Omron 1.5KW/2HP/ 3PH.
The frecuency driver works fine until another motor start, the other motor is from a ventilation system and use a star-delta starter, is a bigger motor 440VAC/20HP/3PH.
I alredy change the star-delta starter with a soft starter (ABB - PSE60-600-70), hoping to solve the problem.
The 2Hp frecuency driver is working fine until the fan starts to work even with the soft starter.
I don´t know if it is a harmonic problem or a EMI (Electromagnetic interference) problem. I was thinking to change the wire connection between the omron vfd to the motor and use a wire with shield. I hope you can give another opinion.
The error code of vfd omron 2HP is E07.3 and already use the manual troubleshooting.

Thanks And best regards.

Your error code indicates that you are getting a high DC bus voltage during constant speed operation. Since it is not taking place on Decel, that can only mean that your line voltage is increasing, or there is some sort of capacitive resonance taking place. So for example if this 2nd motor has power Factor Correction capacitors, that may explain it. Or if, when this larger motor starts, it causes a voltage drop then right afterward the power system adjusts for it with transformer tap changes, then when the motor starting voltage drop is over, the voltage remains high for too long and the drive trips off. There are numerous ways to get to this being a problem.

One general way to solve this is to use a Line reactor ahead of the drive. Any small drive like this should probably have one no matter what. If I were you, I would add the line reactor and see if the problem goes away. if it does, no more worries. If not, it was not a waste of money, because small drives should always be protected with line reactors.

Thank you very much. I´ll try using a Line reactor and I will let you know if the problem is over.
Thank you very much for your attention.