Linz Electric’s DC Alternators For Hybrid Powergen
By Roberta Prandi01 April 2020
Linz Electric developed and launched Phase 9, a comprehensive line of nine-phase direct current (DC) alternators for use in hybrid systems for various applications and for charging all types of batteries available on the market.
These new alternators are dedicated to new, more efficient systems used in power generation and lighting tower applications, as for example telecom towers, gen-set external battery banks, low-voltage light towers, starter systems for aircraft and industrial vehicles, auxiliary power units (APUs), electric cranes, and magnetic lifting cranes.
Phase 9 alternators are available in different DC voltages with a special electronic regulator that offers high control flexibility over the output voltage and/or can be connected to an external controller to manage different parameters of current, voltage and time.
The new Phase 9 series is composed of 2-pole alternators (from 2700 to 3600 r/min) and 4-pole alternators (from 1300 to 2100 r/min).
The low-voltage DC alternators consist of synchronous brushless alternators with nine-phase windings able to guarantee residual alternating current (AC) ripple of less than 1% without batteries. The AC output is converted to DC by means of rectifiers mounted into the control boxes located on top of the machines and provided with built-in fans for ventilation.
The standard voltage range is 24 or 48 Vdc but versions with different voltage or higher current ratings can be provided. Two types of voltage regulators specially designed for the Phase 9 series allow a wide range of control over the output voltage.
Phase 9 alternators can be used with an external battery management system (BMS) for use in battery charging applications, or with a constant voltage control system. With units controlled by external BMS, the user is able to select and set the parameters needed to manage the charging process best suited to the type of battery. In the constant voltage configuration, the machine will supply a steady voltage under both full load and no load, whereas the charging current will depend on the battery charge status. To safeguard and prolong battery life, the current output must be limited in terms of intensity and over time. If the system is not provided with an external control device, then a current limiter must be used and is available on request.
The electronic regulator (AVR) provides:
– precision of voltage output to ±0.5%;
– protection against over-excitation;
– protection against low frequency operating speed.
DC systems by Linz Electric are not limited to a synchronous speed but can be used at fixed speed, at two speeds, or at variable speed within a predetermined range to allow for fuel saving. The adoption of oversized electrical devices ensures that the machine can withstand overloads of +15% for a few minutes
Linz Electric explained that the casing and end shields of the alternators are made of vibration-resistant aluminium alloy. The shaft is high strength steel. A rotor of particularly robust construction is able to withstand drive motor overspeed and is provided with a damping cage. The robust top control box provides ease of access to components and is equipped with additional cooling fans, as well as special output terminals to ensure simple, secure and durable connections. Phase 9 alternators are certified with standard protection IP 23.