Mitsubishi NF-S Series User Manual

ADVANCED AND EVER ADVANCING
MOULDED CASE CIRCUIT BREAKERS
TECHNICAL NOTES
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Mitsubishi NF-S Series Specifications

General

Brand	Mitsubishi
Model	NF-S Series
Category	Circuit breakers
Language	English

Summary

2. FEATURES

2.1 Arc-Extinguishing Device – ISTAC

Mitsubishi's ISTAC technology improves current-limiting and breaking performance.

2.2 Digital ETR

4. CHARACTERISTICS AND PERFORMANCE

4.1 Overcurrent-Trip Characteristics (Delay)

Tripping times for overcurrents at 130% and 200% of rated current.

4.2 Short-Circuit Trip Characteristics (Instantaneous)

Instantaneous trip current specification and adjustability.

4.7 Dielectric Strength

5. CIRCUIT BREAKER SELECTION

5.1 Circuit Breaker Selection Table

Table shows characteristics for selection and coordination.

6. PROTECTIVE CO-ORDINATION

6.2 Interrupting Capacity Consideration

Tables for 230VAC and 440VAC interrupt capacity.

6.3 Selective-Interruption (Discrimination)

Combinations for main-circuit selective coordination.

6.5 I²t Let-Through & Current Limiting

Graphs showing I²t let-through and current limiting characteristics.

6.6 Protective Coordination with Wiring

6.7 Protective Coordination with Motor Starters

Coordination between MCCBs, contactors, and OLRs for motor protection.

7. SELECTION

7.1 Motor Branch Circuit Selection

Discussion on selecting MCCBs for single motors and cold-start operation.

7.5 MCCBs for Transformer-Primary Use

7.7 MCCBs for Thyristor Circuits

9. SHORT-CIRCUIT CURRENT CALCULATIONS

9.1 Purpose of Calculation

9.3 Impedances and Equivalent Circuits

9.5 Calculation Procedures