steveintoronto
Superstar
The regeneration goes to the hotel and running batteries.There is no regenerative braking, because to be regenerative the forces being produced by the wheels braking need to be stored somewhere.
And thus my comment:Regenerated brake energy shall be used to operate the auxiliary inverter in
dynamic braking.
A token amount. (Edit: To clarify, the UPX model uses a fraction of this for hotel power, but not for tractive effort) Ostensibly most is still dumped as heat. Now I'm starting to understand why the UK DEMU equiv class can reach the same top speed or higher with the same prime motor. You'd expect the insertion loss of the generator/electric traction motor circuit to render a lower top speed and acceleration rate compared to a direct-drive mechanical one....except this vehicle isn't recovering the energy claimed. (See: https://en.wikipedia.org/wiki/British_Rail_Class_220 )
But oddly, Metrolinx and Sharyo claim regeneration:
Braking energy is converted into electricity by the auxiliary power generator, and helps to provide onboard lighting and heating.[45]["SMART Technical Specification for Diesel Multiple Units" (PDF). 20 January 2010.
On the retarder:
Vehicles -Draft DMU Technical Specification 1-20-10.pdf10.23 Dynamic Brake System
The car shall have a dynamic brake system. Dynamic brakes shall be
automatically blended with the friction brakes to minimize use of friction brakes
while producing the required service braking rates. The dynamic braking effort
may vary with car speed, but shall provide measurable braking force down to at
least 10 mph. Dynamic brakes shall comply with the requirements of Section 2.
The dynamic brakes shall not be applied through independent operator
command.
A hydrodynamic retarder integral to the transmission shall be provided. The
transmission retarder shall convert car kinetic energy into heat by means of fluid
shear within the transmission operating fluid. This heat shall be rejected to the
transmission cooling system and ultimately to an air-to-water or air-to-oil heat
exchanger. The retarder should be rated for steady state operations of at least
60% of the maximum tractive effort rating of the drive train. The transmission
cooling system shall be designed with enough fluid volume to handle single car
stopping efforts well in excess of the rated, steady-state retarder output.
The transmission cooling system, if not the same as the engine cooling system,
shall follow the same design criteria as stated above.
It shall be possible to cut out the dynamic brakes by means of a sealed switch.
But thank you for making my point Dan.
Last edited: