The MRI monitoring relays are used to monitor alternating and direct current. They automatically detect the AC or DC signal form (50 or 60 Hz). The selector switch on the front is used to choose between overcurrent and undercurrent with or without a memory function. The threshold value for the overvoltage or undervoltage is set using a potentiometer with a scale division as a percentage of the current I to be monitored. The hysteresis is set using a potentiometer with a scale division from 5 to 50% of the set threshold value. The hysteresis value cannot exceed the maximum values of the measuring range. The adjustable switch-on delay time Ti ensures that current peaks or dips are ignored for this time when switched on. Approvals: UL and CSA.
