The VMM ikram shehzad said:
Hello all,i want to ask a question to all of you that what is VMM (voltage monitoring module )? how it work,s? i heard somewhere that it compare 1 phase voltage to other phase voltage. but there is also some setting on it. how to set it,s setting. please tell me briefly.Thank,s and Regard,s.Muhammed Ikram.
the ” VMM ” are ” Electronic Relays ” with 1 or more of auxiliary contacts , and have many functions that are :
– ” Monitor & Compare ” each voltage phase's value with a ” References values ” for ” Up & Down “, and when the difference exceeds a ” References levels ” also for ” Up & Down “, the auxiliary contacts will change their states from ” NO to NC ” or ” NC to NO “.
– ” Monitor & Compare ” the rotation of phases with a ” Reference Rotation “, and when aren't the same, the auxiliary contacts will change their states from ” NO to NC ” or ” NC or NO “.
About the settings, there are many kinds, but normally :
– A special setting for ” Up level ” of voltage given in ” % ” of the designing value.
– A speical setting for ” Down level ” of voltage given in ” % ” of the designing value.
– In some VMM there's also a ” Timing delay ” in seconds.
In some ” VMM ” the references values are fixe by ” 10 – 15% “, so, there's no need to do any setting.