CHAPTER 2: INTRODUCTION
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL 2–7
Accuracy: ...........................................................Fundamental:+/-0.5% of Full Scale
3rd Harmonic at >3V secondary: +/-5% of reading
3rd Harmonic at < 3V secondary: +/- 0.15% of full scale
Max. continuous: 280 V AC
OUTPUT AND NEUTRAL END CURRENT INPUTS
CT primary: 10 to 50000 A
CT secondary: 1 A or 5 A (specify with order)
Conversion range: 0.02 to 20 × CT
Accuracy: at < 2 × CT: ±0.5% of 2 × CT
at ≥ 2 × CT: ±1% of 20 × CT
Burden: Less than 0.2 VA at rated load
CT withstand: 1 s at 80 × rated current
2 s at 40 × rated current
continuous at 3 × rated current
PHASE VOLTAGE INPUTS
VT ratio: 1.00 to 300.00:1 in steps of 0.01
VT secondary: 200 V AC (full-scale)
Conversion range: 0.02 to 1.00 × full-scale
Accuracy: ±0.5% of full-scale
Max. continuous: 280 V AC
Burden: > 500 KΩ
RTD INPUTS
RTDs (3-wire type): 100 Ω Platinum (DIN.43760)
100 Ω Nickel, 120 Ω Nickel,
10 Ω Copper
RTD sensing current: 5 mA
Isolation: 36 Vpk (isolated with analog inputs and outputs)
Range: –50 to +250°C
Accuracy: ±2°C/±4°F for Pt and Ni
±5°C/±9°F for Cu
Lead resistance: 25 Ω max. per lead (Pt and Ni types); 3 Ω max. per lead (Cu type)
NO sensor: >1 kΩ
Short/low alarm: <–50°C
2.2.2 Outputs
ANALOG CURRENT OUTPUT
Type: Active
Range: 4 to 20mA, 0 to 1 mA
(must be specified with order)
Accuracy: ±1% of full scale
4 to 20 mA max. load: 1.2 kΩ
0 to 1 mA max. load: 10 kΩ
Isolation: 36 Vpk (isolated with RTDs and analog inputs)
4 assignable outputs: phase A, B, C output current, three-phase average current,
negative sequence current, generator load, hottest stator RTD,
hottest bearing RTD, RTDs 1 to 12, voltage (AB, BC, and CA),
average phase-phase voltage, volts/hertz, frequency, third
harmonic neutral voltage, power (3-phase Mvar, MW, and MVA),
power factor, analog inputs 1 to 4, tachometer, thermal
capacity used, demand (I, Mvar, MW, and MVA), torque
Courtesy of NationalSwitchgear.com
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