Mikro N302 User Manual

AUXTRIPDELAY

TEST RESET

ms

EARTH LEAKAGE RELAY

N302

N302 Earth Leakage Relay User’s Guide

Indicator

c

b

100

50

150

250

a

a - Auxiliary power indicator

b - Trip status indicator

c - Trip start indicator

e

350

500

1000

3000 INST

d - Leakage current indicator

e - Time delay selector

f - Sensitivity selector

f

g - Sensitivity multiplier selector

h - Reset button

d

80%60%40%20%10%

x10

x100

g

x1

75

50

100

125

mA

150

300 30

200

250

2. Sensitivity Adjustment

The N302 features 2 rotary selector switches for sensitivity ( I n) setting:

( i ) 9- position sensitivity selector oers setting range of 30mA, 50mA, 75mA, 100mA,
125mA, 150mA, 200mA, 250mA and 300mA.

( ii ) 3- position sensitivity multiplier selector switch oers selection of 1x, 10x and 100x.

Example 1: To set I n = 100mA
Step 1: Set sensitivity selector = 100mA
Step 2: Set sensitivity multiplier selector = 100x
I n = 100mA x 100 = 10A

f

g

i - Test button

i

h

1. Light Indicator

( i ) Status Indicators

a

Aux Trip Delay

b

c

O O O No auxiliary power
On O O System normal, no tripping
On O On Trip start, time delay countdown started
On On O Earth leakage tripped

( ii ) Leakage Indicators
a) The earth leakage indicators indicate the amount of leakage current detected and are
expressed as percentage of the set current.

10% - leakage current > 10% of set current
20% - leakage current > 20% of set current
40% - leakage current > 40% of set current
60% - leakage current > 60% of set current
80% - leakage current > 80% of set current

Status

3. Tripping Delay Time Adjustment

- The 9 position time delay selector provides additional delay for fault

e

discrimination.

- Selectable delay are: Instantaneous (no delay), 50ms, 100ms, 150ms, 250ms,
350ms, 500ms, 1s and 3s.

4. Push Button Operations

( i ) Reset Button

- The reset button is for resetting the light indicator and the trip contact after an earth
leakage tripped.

- To reset, press the reset button once.

( ii ) Test Button

- Press and hold the test button for 3s to simulate an earth leakage trip condition.

h

i

5. Output Contact

( i ) Trip Contact

- This is a latching type contact. It operates when tripped.

b) When the N302 detects absence of zero-phase current transformer (ZCT) connection, it will
blink the leakage indicators.

( ii ) Safety Contact

- Contact energized when supply is connected and the relay is functioning
normally.

6. Technical Data

Aux

ZCT

7. Connection Diagram

Auxiliary Supply

N302-240AD............................................ 85 ~ 265 VAC or 110 ~ 370 VDC

Supply frequency.................................. 50Hz or 60Hz

VA rating................................................... Less than 3 VA typical

Setting Ranges

Sensitivity Setting.................................30mA, 50mA, 75mA, 100mA, 125mA, 150mA,

200mA, 250mA, 300mA, 500mA, 750mA, 1A,

1.25A, 1.5A, 2A, 2.5A, 3A, 5A, 7.5A, 10A, 12.5A, 15A,
20A, 25A and 30A.

Time delay setting.................................Instantaneous, 50ms, 100ms, 150ms, 250ms, 350ms,

500ms, 1000ms and 3000ms.

Inputs

Sensor........................................................ ZCT*

Output Contact

Rated Voltage......................................... 250 VAC

Continuous carry................................... 5A (cos = 1.0)

Contact material.................................... Silver alloy

Operating time.......................................15ms max

Expected electrical life........................100,000 operations

Expected mechanical life................... 5 million operations

N 302

1

Safety Contact

7 8 9 10

L1

L2

L3

N

PE

*The EARTH wire must not pass through the ZCT

8. Case Dimensions

72 mm

Trip Contact

!

DANGER

11

12

62 3 4 5

LN

LOAD

97 mm
89 mm

68.0 ± 0.5 mm

Indicators

Auxiliary supply..................................... Green LED indicator

Time delay............................................... Red LED indicator

Trip............................................................. Red LED indicator

Leakage current.................................... 5 red lights for leakage levels

Mechanical

Mounting.................................................. Panel mounting

Front panel............................................... 72x72 mm

Approximate weight............................. 0.5 kg

72 mm

Side

Front

68.0 ± 0.5 mm