It seems appropriate to write down some preliminary assessments on the latest engine testing. The activity now numbers 90 separate tests. This includes half of the six engine, six motor series. I addition several engines have been prepared for sale. For these, the engines are being run on DC with no electronic module, constant DC (Rail Pro) and DCC. Most of these are being run with an added 154 gram weight to get a derivative for the various configurations. This group of tests will lead to several posts focused of the various aspects.
In the mean time, some general observations are as follows:
- motors matter for performance, but other factors matter more.
- Outside frame trucks yield better results than inside frame trucks.
- six axle diesels pull more than four axle.
- the engine weight derivative varies for different motors and configurations. The six axle weight derivative is less than the four axle. That could be due to the initial weight being heavier.
- wheel material & diameter have many benefits. Improved pulling capability and better low speed performance.
- as has been seen before, electronic modules reduce the engine performance. This shows up the most at higher power(volts). In the lower power end, the PWM allows the motor to run at lower average voltage and a lower sustained velocity. The DC lab supply does not have a PWM so the modules show an improved low speed performance. A normal DC supply would have PWM, so that benefit will disappear. The fixed DC (Rail Pro) module has significantly less degradation in performance.
- the electronic modules pull more cars than the no module case. The fixed DC improvement is better than the DCC case. Again the DCC power loss is causing this. This improvement is likely coming from the PMW occurring during the acceleration on the grade.
- the pulling capability is related to the amount of current level change that the engine can achieve. This is capped by the motor stall current at the voltage. The difference between that and the engine only current draw represents the power available. How much the engine can achieve will drive it pulling capability. The motor only sets the ideal difference, no load to stall current. The actual maximum current level is set by other factors; like engine weight, number of wheels, wheel material and wheel elasticity.
So far a number of interesting results have forced more thought. A number of questions are still on the table.
stay tuned, more to come.
