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LT NGR TS

The document provides a technical specification for a 433VAC neutral grounding resistor system. It outlines 10 key components: 1) a neutral grounding resistor, monitoring relay, and ground fault relay, 2) a resistance of 330 ohms using nichrome nickel cronium wire, 3) an IP55 powder coated enclosure, 4) a current transformer with a ratio of 10/0.01 amps and other specifications, 5) sensors for the fail safe relay and protections, 6) tripping conditions for the neutral grounding resistor fail safe relay, 7) additional sensors for signals to the fail safe relay, 8) an epoxy molded isolated transformer for protection circuits, 9) requirements to meet C

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Prasenjit Maity
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64 views1 page

LT NGR TS

The document provides a technical specification for a 433VAC neutral grounding resistor system. It outlines 10 key components: 1) a neutral grounding resistor, monitoring relay, and ground fault relay, 2) a resistance of 330 ohms using nichrome nickel cronium wire, 3) an IP55 powder coated enclosure, 4) a current transformer with a ratio of 10/0.01 amps and other specifications, 5) sensors for the fail safe relay and protections, 6) tripping conditions for the neutral grounding resistor fail safe relay, 7) additional sensors for signals to the fail safe relay, 8) an epoxy molded isolated transformer for protection circuits, 9) requirements to meet C

Uploaded by

Prasenjit Maity
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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MATERIAL TECHNICAL SPECIFICATION FOR 433VAC SYSTEM:-

1. Neutral Grounding Resistor on 415 VAC side for transformer with NGR fail safe relay,

Monitoring relay, and Ground Fault relay (Earth Fault) Monitoring Relay of 30mA to 750 mAmp, Aux.
Supply of the

Relay: 230V AC. AUXILIARY SUPPLY

2. Resistance- 330 Ohms, NICROME NICKEL CRONIUM WIRE WOUND INDUSTRIAL TYPE Resistor
(Make- Reputed)

3. Enclosure of NGR- IP 55 Powder Coated, Heat Proof Covered Outdoor Type for Underground
Mines.

4. CT- Suitable for 433VAC system Voltage- Ratio: 10/0.01 Amp, 50 Hz, Burden- 5 VA, Insulation
Level: 2 KV, Class: 1.0, Freq: 50Hz, Type: Ring Type Epoxy Moulded, Dia 70 mm Inside Resistor
(Make- Reputed)

5. Sensor- Sensing of signals for fail safe relay and protections of high voltage, high insulation level
and epoxy moulded Resistor (Make- Reputed)

6. Tripping condition of NGR fail safe relay with NGR monitoring relay and ground fault monitoring
relay 433VAC Resistor (Make- Reputed)

a) Neutral Connection Open

b) Ground Connection Open

c) Neutral grounding Resistor connection open

d) Earth Fault Trip

f) In all fault of the transformer Neutral terminal and ground terminal primary or secondary breaker
will trip

g) In all fault of the transformer Neutral terminal and ground terminal buzzer will operate

h) Test reset push button mounted on cover for NGR system Check, No external power supply or test
equipment is required.

j) NGR Monitoring fail safe relay.

k) Neutral to Earth through Resistance to be connected by cable or Insulated strip.

l) Sensor open circuit.

7. Sensor– Sensing of signals for Fail Safe Relay and Protections of High Voltage, High Insulation
Level, Ensure Healthy Condition of NGR, Epoxy Moulded.

8) Epoxy Moulded 2 KV Isolated Transformer to protection circuit of Fail Safe Relay.

9. The Complete NGR set must full fill the CERA-2010 or latest.

10. The NGR shall be rated for 10 minutes continuous duty.

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