1. Do permanent magnets lose their magnetism over time?
A misconception amongst users is that strength of the permanent magnets degrades over time and that it will eventually become inert, rendering the alternator useless. This misconception is facilitated by the belief that the existence of magnetic fields requires a constant output of energy. This is completely false, and many RFL alternators currently being used in harsh environments for many years would easily disprove this belief. Consequently, RFL confidently offers a longer warranty period than conventional brushed or brushless units.
2. Do permanent magnets demagnetise under heavy loads and short circuits?
No, the RFL rotor design was specifically developed to eliminate this problem. RFL Alternators have been used for a number of years for heavy motor start applications with zero loss of magnetic flux. All RFL Alternators have been subjected to short circuit tests at maximum rated temperature and also show zero loss of magnetic flux.
3. How do RFL permanent magnet alternators differ from current permanent magnet alternators?
The current permanent magnet alternators are surface mount rotors which are susceptible to demagnetisation under heavy loads and short circuits. The technology used in RFL Alternators involves using embedded magnet design to achieve high performances along with variable reluctance which reduce the voltage drop under load. The RFL design also minimises the volume of magnets in the rotor, which keeps costs down.
4. Why are RFL Alternators more efficient than current conventional alternators?
RFL’s patented design means that there are no energy losses in the rotor. The only losses are seen in the stator windings.
5. How is voltage controlled without an AVR?
The rotor design of the alternators naturally regulates the AC waveforms under load, negating the need for an AVR. Voltages are set at manufacture and fixed for the life of the alternator.
6. Can RFL Alternators withstand harsh environments?
RFL Alternators standard 4 pole units are protected by a special coating to prevent corrosion by salt water or dust and grit particles. For the harshest environments, RFL recommends using the fully enclosed IP65 enclosure which is able to withstand high pressure water jets from any direction, and total protection from ingress of dust. Thus, are ideally designed tough environments for road and rail transport or marine applications.
7. How are RFL Alternators mounted?
The mounting feet are adjustable along the length of the alternators. Due to the short lengths and lighter weight of RFL’s design, the alternators can be completely supported by the flange mounting. RFL currently offers SAE3, SAE4, SAE5 flange mounting with flywheel connections for 4 pole units. All 2 pole units are mounted by a V-type PTO shaft mounting for small diesel and petrol engines.
8. Can the alternators be used at 50/60Hz or at different voltages?
Yes the alternators are able to run at either frequency, however as the voltage is directly related to the frequency or RPM, RFL will wind the alternator during manufacture differently according to your requirements.
9. Can I use the alternator as single-phase as well?
The RFL alternator typically have 3 sets of windings in the stator, making it ideal for 3-phase. Single-phase is also possible simply by using 1 of the 3 phases. For a stronger performance, RFL recommends a dedicated delta-connected single-phase. As a general rule in the industry, single-phase is capable of achieving 60% of the 3-phase power.