Murphy ELD2, ELD5, ELD4 User Manual

ELD series

The Generator Controls Division of

R

Frank W. Murphy Manufacturer
Frank W. Murphy Southern Division

Frank W. Murphy Ltd.

Murphek Pty. Ltd.

Murphy Switch of California

Murphy de Mexico S.A. de C.V.

Frank W. Murphy Pte, Ltd.
Frank W. Murphy Ltd. en France

31

25

25

EMA

ELD

162

136

176

148

RED

L2 or N

EARTH LEAKAGE DETECTOR UNITS

A range of versatile and economical earth leakage
detection relays. Each unit is housed in a robust, glass
filled nylon case: an aperture in the casing allows the
installation cabling to be passed through the integral
core balance transformer.

The electronic circuitry combines a stable amplification
of the transformer output with an ability to give high
sensitivity and fast operating speeds. Detection of an
earth fault results in the energisation and latching of the
unit's SPCO relay. The unit is reset by momentarily
removing the auxiliary supply.

Protection from excessive fault current and supply
transients are fitted as standard, as is filtering to allow use
with chopped waveform and variable drive applications.
A 'test' facility is supplied in the form of a button, either
pre-fitted into the unit's front facia or connected remotely.

Electrical connection on standard units is by a colour coded,
6 way flying lead, with terminal blocks available as an
option. Each unit may be mounted on a front panel or back­plate using two 3mm threaded inserts; an optional mounting
assembly (part no. EMA) is also available for front access
back-plate mounting.

Standard units include:

ELD2 Basic unit, with 20mS typical trip time.

Fast response to earth leakage faults.

ELD4 As ELD2, but with longer trip delays, 80mS

to 5 secs. Prevents nuisance tripping in motor
protection circuits and allows time discrimination
in distribution networks.

ELD5 As ELD4, but with an adjustable trip delay.

Available in various time ranges up to 2 seconds.

With options:–

'VS' Adjustable trip current (via front facia potentiometer.)
'HT' High temperature specification (to +60°C ambient).
'TB' Screw terminal connectors instead of flying leads.
'RC' Special calibration and 1m wiring for use with

remote CTs (for RTCs of >125mA).

Variations on our standard units and options are also
available: please call with your requirements.

When ordering, please specify:–

a) Product type number (ELD2, ELD5, etc.)
b) Auxiliary supply voltage
c) Trip current (fixed, or variable range for VS option)
d) System frequency (50, 60 or 400 Hz.)
e) Trip delay time (fixed or variable, according to model)
f) Additional options, if required.

Accessories:–

EMA Mounting assembly for ELD series.
Remote CTs A range of remote core balance/current

transformers, enabling specially
calibrated ELD units to be used with
larger cables. Available in a range of
sizes, with or without a magnetic screen
(see sheet M060101 for full details).

M060501

Issue 4, revised 09/98

Catalogue section 75

Product Specification

Power supply:

operating voltages (ranges)
(all for 50/60Hz.)

110V AC (100 – 120 V)
230 V AC (200 – 250 V)
415 V AC (380 – 440 V)

power consumption < 100mA

Control:

trip levels fixed and variable, 10mA to 30A
trip point accuracy to BS4293

Relay output: (ratings for resistive load)

SPCO contacts, rated

3A @ 250V AC/30V DC,

1A @ 440V AC

Physical:

operating temperature

standard unit: –25 to +40°C

'HT' spec.: –25 to +60°C

weight (with EMA) approx. 330 g

Connection (standard unit)

L1

External

Test

Button

BLUE

BLACK

Test

ELD

GREEN

WHITE

YELLOW

Dimensions (mm)

4

3

59

Incorporating Modex Automation

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Since 1939

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