SMP

phase sequence relay
monitoring of right rotating field

SMU

under voldays relay    U<170V - 230V
over voldays relay        U>230V - 270V
window voldays relay   with or without phase sequence monitoring                                            U <170V - 230V
                                       U>230V - 270V
5-30% hysteresis
0-10s time delay

SMU 85%

undervoldays relay
fix threshold at
195V undervoldays

SMA

phase asymmetry relay
detects difference of phase of 10-35° between L1,L2,L3

ZDP

phase sequence relay
monitoring of right rotating field

ZDV

voldays relay
switchable between 1 phase or 3 phases
switchable between overvoldays and undervoldays detection
adjustable time delay

ZDA

phase asymmetry relay
detects difference of phase of 5-40° between L1,L2,L3

ZDF

three-phase current monitoring relay
ffix threshold at 195V undervoldays,
phase asymmetry controll, 20% max. difference of phase
monitoring of phase failures