U... three-phase monitor relays
The U type three-phase voltage monitors are suitable for
complex protection of three-phase loads (mainly motors)
against phase-asymmetry and fals sequence of line
voltages as well as symmetrical increase or decrease of
line voltage. Their operation does not require neutral
conductor. The operating value can be set by turn-knob.
The breaking occurs with delay, for this reason the monitor
relay does not sensitive to voltage transients.
In the type-mark of voltage monitor the letter U is followed
by the letter-combination referring to the kind of protection:
A - phase asymmetry
S - phase sequence
N - line voltage increase
C - line voltage decrease
|15 combinations of the four kind of protection are available:|
The delay time is not adjustable at above mentioned
versions. The delay time of breaking is adjustable by turnknob
in case of types: UAt, UASt and UASNCt.
|Rated insulation voltage
|Rated control voltage (Uc)
||3 x 400 V 50 Hz
3 x 380 V 50 Hz
3 x 190 V 50 Hz
+15 ... -20%
|Asymmetry at turn-off
|Voltage increase at turn-off
% ... (1,15xUc)+5%
|Voltage decrease at turn-off
|Degree of protection
The detailed technical description of the product family is in the printed catalogue
"TIMERS MONITORS ELECTRIC DEVICES FOR INSTALLATION"
For further information see the