Materials and construction
The stator is made from 29 gauge, M15 electrical steel laminations that are stacked and bonded. Trapezoidal bars of aluminum are inserted into the stator core, exceeding 90% slot fill (compared to less than 50% for motors with traditional copper windings).
The rotor is made from precision machined steel bar and has twelve high-temperature (300°C) samarium–cobalt (SmCo) magnets mounted on its circumference. The magnets are retained with a composite band and the rotor is balanced prior to assembly.
Following our commitment to high quality, high performance materials and components such as Nachi bearings, are used throughout our product line. 30mm double-row angular contact bearings are standard.
The rear cover is comprised of glass-filled, high temperature thermoplastic, which is precision machined. A magnetically coupled coolant pump may be added, when necessary.
eCycle SolidSlot Construction
Integrated electronics are mounted on the rear cover and cooled with a brushless fan. This enables the SolidSlot brushless motor to be operated directly from a battery or with an industry standard DC motor controller.
For increased flexibility, the electronic commutator can be mounted remotely and cooled by air or liquid.
A broad range of configurations are possible, some as simple as adding the desired shaft adapter. In general, the SolidSlot™ can support a broad range of applications, including mobile hydraulics, marine propulsion and generation, robotics, integrated starter/alternators, diesel, gasoline and gaseous fuel gen-sets, and large centrifugal pumps.
As a result of the electronic commutator, the SolidSlot™ brushless motor/generator may be used to directly produce DC power through high efficiency synchronous rectification. The voltage is proportional to speed, and the resultant DC power may be used for battery boosting or to power an AC inverter.
Integrated Starter Alternator
eCycle’s brushless machines are equally capable as motor and generator. For many high voltage applications, diode or passive rectification is efficient. However, low voltage, and especially high current applications are best served by synchronous rectification, because diodes have a proportionally high voltage drop, whereas the voltage drop for MOSFETs is a function of their on-state resistance. This is why commutation electronics with high current capacity are very efficient in generator mode.
For many years, eCycle has provided 1to 10kW generators capable of starting small engines. In these applications, which usually involve battery charging, the voltage output is proportional to engine speed, as set by the throttle. When the engine is loaded down by high current draw the voltage is reduced, but as the state of charge increases, the speed and voltage naturally elevate to match the battery. This represents a simple starter/alternator configuration.
More sophisticated systems demand a power supply like our Buck/Boost regulator that can ensure the desired voltage, independent of engine speed, as well as limit current, usually associated with engine starting. A vehicle’s powertrain is the most common example. Significant torque, and therefore current, is required for engine starting, after which the generator/regulator must be able to charge batteries over a range of speed.
It is in this area where the regulator’s ability to trade amps for volts at low speed and volts for amps at high speed is so important.