METERING VOLTAGE FAILURE ALARM RELAY
(SINGLE PHASE)
Type VFR144

The Metering Voltage Failure Alarm Relay (Single Phase) type VFR144 is used primarily to monitor the measuring and auxiliary supplies to single phase reactive energy meters for the purpose of detecting faults such as fuse failures. It will give an alarm when either or both of the monitored supplies fall below a defined value.

The output contacts automatically return to the 'reset' position on removal of the fault condition.

The relay is powered from the auxiliary supply and has a low VA burden on both the measuring and auxiliary supplies. Two sets of changeover 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 relay is housed in a case suitable for DIN rail mounting inside an equipment cubicle. Input and output connections are made to screw terminals on the front face. There are no controls requiring set up prior to installation.

Complies with specification NGC-EM44 (1990). 

SPECIFICATION
INPUT VOLTAGE
Measuring Supply:                  63.5Vrms (+15% -30%)
Auxiliary Supply:                     63.5Vrms (+15% -30%)
INPUT FREQUENCY RANGE    47 - 53 Hz.
NOMINAL INPUT BURDEN
Measuring Supply:                  0.1VA cosų 0.8
Auxiliary Supply:                     1.1VA cosų 0.9
RESET CONDITION                 The MVFA will be in the RESET condition
                                              when both the voltages applied to the
                                              measuring and auxiliary supply inputs
                                              have attained 80% of  the nominal value
                                              (output relay energised).
OPERATE CONDITION             The  MVFA shall change from the RESET
                                              to the OPERATE condition when either, or
                                              both the measuring and auxiliary supply
                                              voltages have fallen to 50% of the nominal
                                              value, for a period of 1.5 seconds (-0,+4 secs).
OUTPUT CONTACTS                Two sets of changeover contacts.
CONTACT RATING
Power                                     3W max
Voltage                                   175V dc max
Current                                    0.25A max
Carry current                            1A max.
INSULATION                            2KV rms between all input circuits, output
                                              circuits and earth.
ENVIRONMENT                        EES1989 Class C.
ELECTRICAL INTERFERENCE   EES1989 Class Z.
CASE
Dimensions:                             W : 55mm H : 73mm D : 113mm.
Weight:                                    370gms.
Terminal face:                           Polycarbonate/GV/V-0, grey.
Cover:                                      ABS/V-0, grey.
Flame retardancy:                     Self-extinguishing, to UL94 Class V-0
                                               To VDE0304 Degree 1.
Mounting Details:                      Snap mounting on "top hat" rail
                                               DIN EN 50 022-35
                                               BS5584.
Terminals:                                Plus-minus M3.5 terminal screws with self-lifting
                                               connection washer.  Torque setting 1Nm.

Convex Design Limited

email:sales@convexdesign.co.uk

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