Alternator A.R.K7G

A.R.K7G Alternator – PMG Excited, Brushless, and Heavy-Duty Industrial Alternator

The A.R.K7G alternator, developed by Arken Power Solutions, is a high-efficiency, three-phase, brushless synchronous alternator equipped with PMG excitation and MX321 AVR for exceptional voltage stability and superior transient performance. Offering ±1% voltage regulation, THD below 5%, and efficiency up to 96.6%, it delivers reliable, clean, and consistent power output for demanding industrial, rental, and standby generator applications. With Class H insulation, IP23 protection, and sealed-for-life bearings, the A.R.K7G ensures long service life and minimal maintenance. Fully compliant with IEC60034, BS5000, NEMA MG1-22, CSA C22.2-100, and ISO9001, this alternator represents Arken’s commitment to quality and durability in professional-grade power generation.

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Alternator Model

A.R.K7G

50Hz (kVA)

1825

60Hz (kVA)

2163
Control System SELF EXCITED
A.V.R. MX341 WITH PMG
Voltage Regulation± 1.0 %
Sustained Short Circuit >300% OF RATED CURRENT
Rated Power Factor0.8

Electrical Performance

  • Type: Three-phase, brushless, PMG-excited synchronous alternator

  • Frequency: 50 / 60 Hz

  • Power Factor: 0.8

  • Voltage Range: 380/220V – 480/277V (configurable in star, delta, or parallel star)

  • Voltage Regulation: ±1.0%

  • Total Harmonic Distortion (THD): <5% (balanced linear load), <1.5% (no-load)

  • Sustained Short Circuit Current: >300% rated current for 10 seconds

  • Efficiency: Up to 96.6% (depending on frequency and load)

  • Overload Capacity: 110% for one hour in a six-hour cycle

  • Telephone Harmonic Factor (THF): <2%

  • Telephone Interference Factor (TIF): <50

  • Short Circuit Ratio (1/Xd): 0.17 typical

  • Power Ratings (Winding 311):

    • 50 Hz: 1340–1700 kVA (Efficiency 96.3–96.6%)

    • 60 Hz: 1520–2163 kVA (Efficiency 96.1–96.5%)

  • Reactances (Per Unit at Rated kVA):

    • Xd (Synchronous): 2.02–3.29

    • X’d (Transient): 0.21–0.33

    • X’’d (Subtransient): 0.07–0.08

    • Xq (Quadrature): 1.90–3.08

    • X’’q (Quadrature Subtransient): 0.20–0.24

    • X₂ (Negative Sequence): 0.16–0.17

    • X₀ (Zero Sequence): 0.12–0.14

    • Leakage Reactance (XL): 0.02–0.03

  • Time Constants:

    • Transient (T’d): 0.33 s

    • Subtransient (T’’d): 0.03 s

    • Armature (Ta): 0.03 s

    • Open Circuit Field (T’do): 3.41 s

Construction & Design

  • Insulation Class: H (125°C rise at 40°C ambient)

  • Protection: IP23 (optional IP44 with 5–10% derating)

  • Cooling: Self-ventilated air cooling system

    • 50 Hz: 2.64 m³/s (5600 cfm)

    • 60 Hz: 3.17 m³/s (6720 cfm)

  • Frame: Rigid steel structure with cast aluminum front and rear covers

  • Stator: Double-layer winding, 2/3 pitch design eliminates triple harmonics

  • Rotor: Damped rotor dynamically balanced to BS6861 standards

  • Bearings:

    • Drive End: 6319 (ISO standard, sealed-for-life ball bearing)

    • Non-Drive End: 6228 (ISO standard, sealed-for-life ball bearing)

  • Overspeed Capability: 120% of rated speed (2250 rpm)

  • Leads: 12 reconnectable leads for star, delta, or parallel star configuration

  • Inertia (WR²): 44.59–45.59 kg·m²

  • Winding Resistance:

    • Stator: 0.00093 Ω/phase (22°C, star connection)

    • Rotor: 1.65 Ω (22°C)

Dimensions & Weight

  • Rotor Weight: 1431–1494 kg

  • Stator Weight: 1852 kg

  • Complete Alternator Weight: 3541–3704 kg

  • Shipping Weight (Crated): 3614–3704 kg

  • Packing Dimensions: 216 × 105 × 154 cm

Regulation & Control

  • Excitation System: PMG excitation with brushless AVR

  • AVR Models: MX321 (standard), MX341, SX460, SX440, AS440 (optional)

  • Voltage Regulation Accuracy: ±1.0%

  • Parallel Operation: Supported (AVR-dependent)

  • Protection Features:

    • Stator winding and bearing overheat protection

    • Anti-condensation heater (optional)

    • Low-speed voltage drop protection

  • RFI Suppression: Complies with BS EN 61000-6-2 & BS EN 61000-6-4, VDE 0875G/N

  • Standards Compliance: IEC60034, GB755, BS5000, NEMA MG1-22, CSA C22.2-100, AS1359

  • Certification: ISO9001 Quality Management System

Environmental Parameters

  • Operating Temperature: –15°C to +40°C

  • Relative Humidity: Up to 95% (non-condensing)

  • Altitude: Up to 1000 m without derating

  • Cooling Air Requirement: 2.64–3.17 m³/s depending on frequency

  • Noise & Vibration: Dynamically balanced per BS6861 mechanical standards

Performance Summary

  • Efficiency Range: 96.1–96.6%

  • Voltage Dip (Transient Load): ≤25% at 0.8 PF

  • Recovery Time: <0.5 seconds

  • Locked Rotor Motor Starting: >300% rated current

  • Applications: Prime power, standby, rental, telecom, mobile, refrigeration, lighting tower, and railway generator systems

Datasheet

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