Hello,

Can DCM be used with input voltage above its nominal?

There is an existing converter transformer with secondary voltage 740V and a motor with rated voltage 770V DC. Drive power is 1500kW and rated current ca. 2000A.

Is it normal to use for this drive one DCM (2Q) with output 2600A and 830V DC? Rated input voltage is 690V +10%/-20%, so upper limit  (690V*1,1 = 759V) is not overrided.

The same situation with another drive (motor voltage 930V), but transformer's secondury voltage is 870V and DCM (2Q) 1900A with input 830V AC.

Please give me some advices on both cases.

Hello,

With rated AC input supply of 690 V 3 phase AC, 6RA 80 DC drive out put would be 830V DC. AC voltage tolerance +10% & -20% means Drive DC out put will be 830 V DC even when 3 phase supply is low as 552 Volt AC or hihg as 759 V AC.

For 930 V DC motor armature voltage you need to select drive with incoming supply rating of 3 ph 830 V AC.

Please refer attached sheet for more information.

Do I understand you correctly: it's possible to connect DCM with 690V AC to net voltage 740V (and same DCM with 830V AC to net voltege 870V) without any troubles?

Thank you.