Alpha Compact 28/150 alternator (without pulley)
In stock
Technical specifications
Technical specifications
| Series | Alpha Compact |
| Nominal voltage | 24.0 |
| Nominal current | 150.0 |
| Power | 4.2 |
| Max rotation speed | 15000.0 |
| Cut-in speed | 1300 |
| Idle current | 28.0 |
| Mounting style | Custom (to be adapted) |
| Rotation direction | Bidirectional |
| Galvanic isolation | Isolated from ground |
| Field control type | External |
| Housing temperature sensor support | Oui |
| Min pulley diameter | 48.1 |
| Max pulley diameter | 89.0 |
| Min pulley ratio | 2.5 |
| Max pulley ratio | 3.5 |
| Cooling method | Internally optimized thermal cooling |
| Cooling fan count | 2.0 |
| Max operating temperature | 120.0 |
| Weight | 7.9 |
| Marine-ready | Oui |
| Airflow direction | Internal twin-flow (side suction) |
| Bearing lubrication | High-temperature grease, lifetime use |
| Belt alignment tolerance | Strict (laser alignment recommended) |
| Case design | Open for maximum ventilation |
| Diode bridge type | High-power avalanche diodes |
| Alternator efficiency class | High efficiency (>60%) |
| Field terminal | Yes |
| Magnetic technology | Claw-pole rotor |
| Number of phases | 3 |
| Rotor balancing | High-precision dynamic balancing |
| W signal connection (tachometer) | Yes |
| Stator winding | Holding pattern |
| Temperature sensor included | No |
| D+ / Excitation terminal | Yes |
| Bearing type | High-temperature sealed ball bearings |
| Belt drive compatibility | Multi-ribbed belt (Serpentine) |
| Charge algorithm | 3 steps |
| Charge voltage | 28 |
| Compatible engine type | Inboard marine engines |
| External regulator model | Mastervolt Alpha Pro |
| External regulator required | Yes |
| Housing material | Aluminum |
| Insulation class | Class H |
| IP rating | IP20 |
| Optimized for lithium batteries | Yes |
| Maintenance-free | Yes |
| Max output current | 150 |
| Negative stud size | M8 |
| Negative terminal | Dowel |
| Positive stud size | M8 |
| Positive terminal | Dowel |
| Recommended cable gauge (up to 5 m) | 50 |
| Recommended fuse rating | 200 |
| Reverse polarity protection | No |
| Salt spray protection | Yes |
| Short-circuit protection | Yes |
| Supported battery chemistries | Lithium-Ion, Lead-Acid, Gel, AGM |
| Thermal protection | Yes |
| Vibration resistance | High (marine-grade design) |
Detailed description
Detailed description
Mastervolt’s Alpha Compact 28/150 alternator is a high-performance charging solution designed for vessels equipped with large-capacity 24V battery banks. With a 150-amp output current, this model ensures fast and optimal recharging, even at low engine speeds.
Compact design and power-to-weight ratio
Distinct from the standard Alpha series due to its reduced footprint, the Alpha Compact range was developed to fit in tight engine compartments. Weighing just 7.9 kg, this 28/150 model delivers exceptional power density. Its internal architecture promotes efficient thermal cooling, allowing it to sustain high continuous charging currents without overheating the generator.
System integration and compatibility
This specific model ships without a pulley, providing the technical flexibility to install a custom pulley, such as a multi-groove (serpentine) belt, perfectly aligned with your engine’s mechanical configuration. To fully utilize its capabilities and ensure battery safety (especially for Lithium-Ion banks), this alternator must be paired with an external charge regulator such as the Mastervolt Alpha Pro, which guarantees a 3-stage smart charging cycle and rigorous thermal protection of the system.
Expert opinion
Expert opinion
Pol CONIN
Digital Manager
« Maximum power density for high-capacity battery banks »
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