pic: 4908 Prototype West Coast Drive

[WSiggs]

Thanks everyone for the feedback! All of your comments have been helpful, and I will take this information back to my team to discuss it.

Originally Posted by Lil' Lavery

I fully understand both 3CIM transmissions and dual-speed transmissions for drivetrain, and have used both in the past. However, a 3CIM dual-speed transmission strikes me as an exercise in overkill. The improved acceleration (when compared to a "standard" 2-CIM single speed) and pushing power are accomplished with either solution. Similarly, with the additional CIMs you can creep your top speed above a KoP transmission while retaining superior torque without the need for shifting. However, when you incorporate BOTH the 3rd CIM and the dual-speed, you get the downsides of both. You have the additional weight, additional space usage, the need for pneumatics, the usage of additional PWM outputs, the use of additional speed controllers, the additional current draw, and the additional financial cost. For only a minor performance improvement over either a 2-speed or 3-CIM single speed, you're tacking on a lot of additional costs. You're also inviting the risk of tripped circuit breakers if you're not careful about your power consumption in high gear (especially if you're not traction limited) and programming when you shift gears.

Thanks, you likely saved our team a lot of trouble by letting us know these downsides. When designing this chassis we were unaware that we should be concerned about these factors.