METERING VOLTAGE FAILURE ALARM RELAY (THREE PHASE)
Types VIR344, VIR345, VIR43 & VIR431


Metering Voltage Failure Alarm Relays are sensitive phase imbalance alarm relays intended primarily for use on metering 3-phase 3-wire voltage transformer circuits for detecting faults such as fuse failures, but may also be used on 3-phase 4-wire supplies where the phase to phase voltage is 110V. The units can also be supplied calibrated in % NPS voltage.

The relay can be self powered from the supply being monitored or powered from an auxiliary supply enabling a very low burden to be applied to the measuring supply.

Two modes of operation, A or B, are available, either factory set or selectable by the installer. For 'Mode A' operation the output relay is normally de-energised and gives an alarm condition after the preset time delay, for a phase imbalance of the 3-phase supply voltage equal to or greater than the imbalance setting or for a loss of a single phase of the supply. There is no alarm for total loss of the supply. For 'Mode B' operation the output relay is normally energised and gives an alarm for the two conditions above but will also give an immediate alarm for total loss of the auxiliary supply. When separate measuring and auxiliary supply inputs are used there will be no alarm for a loss of a single phase of the auxiliary supply.

The relay will detect voltage imbalance over the range 1 to 8.5 percent in 0.5 percent steps using the panel-mounted rotary switch. A time delay period from zero to 75 seconds in 5 second steps may be set using the second panel-mounted rotary switch. Relays with different imbalance and time delay ranges can be supplied to order.

Two sets of changeover output contacts are provided and all input and output circuits are isolated from earth and from each other to a level of 2KV rms at 50Hz. The output contacts automatically reset to the 'normal' position on removal of the fault condition.

The relay is housed in a case suitable for DIN rail mounting or screw fixing inside an equipment cubicle. Input and output connections are made to screw terminals on the front face which also contains the setting controls and a self-resetting LED indicating alarm condition.

Complies with specifications NGC-EM43(1990) and NGC-EM44(1990). 

SPECIFICATION
INPUT VOLTAGE       3 phase 110V rms (+15% -20%)
INPUT FREQUENCY  47 - 53Hz.
INPUT BURDEN
Measuring Supply:      R-Y  0.04VA   B-Y   0.04VA         TOTAL 0.1VA cosų 0.8
Auxiliary Supply:         Mode A Balance State               Mode A Alarm State
                                 Mode B Alarm State                   Mode B Balance State
                                     R-Y   0.7VA                                R-Y   0.9VA
                                     B-Y   0.7VA                                B-Y   0.9VA 
                                 TOTAL 1.4VA cosų 0.8               TOTAL 1.8VA cosų 0.8        
IMBALANCE RANGE   Settable from 1.0 to 8.5 percent in steps of 0.5 percent.
                                 Accuracy ±0.5 percent imbalance.
                                 (Can also be supplied with a settable range of 1.0 to 8.5 percent NPS.)
PERCENTAGE            The difference between the amplitude of the highest and lowest measured
IMBALANCE               voltage, expressed as a percentage of the nominal input voltage.
TIME DELAY               VIR344 - 0-75 seconds in multiples of 5 seconds
                                 VIR345 - 0-150 seconds in multiples of 10 seconds
                                 VIR43   - 0-75 seconds in multiples of 5 seconds
                                 VIR431 - 0-300 seconds in multiples of 20 seconds
                                 (other time delays to order).
                                 Accuracy +0.5 seconds (crystal controlled).
OUTPUT CONTACTS   Two sets of changeover contacts.
CONTACT RATING      Power:           60W/125VA max (resistive)
                                  Current:          2A max
                                  Voltage:                      250V max
                                  Carry current:  3A max
OUTPUT INDICATION  Self resetting LED indicator - illuminated during an alarm condition,
                                 (except for a total loss of supply - MODE B only).
INSULATION               2KV rms between all input circuits, output circuits and earth.
ENVIRONMENT           EES1989 Class B.
ELECTRICAL
INTERFERENCE          EES1989 Class Z.
CASE 
Dimensions:                W: 100mm  H: 73mm  D: 113mm.
Weight:                       530gms.
Terminal face:              Polycarbonate/GV/V-0, grey.
Cover:                         ABS/V-0, grey.
Flame retardancy:       Self-extinguishing to UL94 Class V-0 and VDE0304 Degree 1.
Mounting Details:        1)   Snap mounting on "top hat" rail. DIN EN 50 022-35. BS5584.
                                  2)  Screw mounting using diagonally-opposite lugs on rear face.
Terminals:                   Plus-minus M3.5 terminal screws with self-lifting
                                  connection washer.  Torque setting 1Nm.
ORDERING INFORMATION

VIR344 Specification NGC-EM44(1990). Internally selectable to 'Mode A' or 'Mode B'. Time delay - 0-75 seconds in steps of 5 seconds. Self powered from the supply being monitored.

VIR345 Specification as VIR344 except that the time delay is settable from 0-150 seconds in steps of 10 seconds.

VIR43 Specification NGC-EM43(1990). Internally selectable to 'Mode A' or 'Mode B'. Time delay - 0-75 seconds in steps of 5 seconds. Separate measuring and auxiliary supply 3-phase inputs.

VIR431 Specification as VIR43 except that the time delay is settable from 0-300 seconds in steps of 20 seconds.

Other configurations can be supplied to order.

 

Convex Design Limited

email:sales@convexdesign.co.uk

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