# Electric Low gear



## akseminole (Jan 5, 2014)

I have an idea that needs outside input. 

I am planning an AC Off Road truck. 
While I'm certain that the torque from the 650 amp controller would be perfectly adequate, I have an idea for an *electric Low gear*.

Essentially the idea is to run the 96v controller for highway speeds and most Off Road situations. When I decide that I want to crawl, I turn off my primary system and activate a low voltage high amp inverter (800). 

The primary sticking point had been how to connect both inverters to the one motor without the 96v controller potentially harming the lower voltage inverter while it is on. 

I have found a 600v 420amp continuous, 3 Phase AC contactor. My thought is to wire the 36v 800 amp controller to the AC motor through the contactor to isolate it from the 96v 650 amp controller. The low tech solution would be just to swap leads, but that seems like a great way to wear out the attachment points on the inverters.

I am aware that the torque knee would drop off, probably before 1,000 rpm.
This is only for situations between 1-15 mph, sort of like putting a Jeep Rubicon into 4 low.
As I have not completely committed to this idea, I had purchased a lower power inverter to see if the low rpm range would even be adequate for my needs. A 36v 500A inverter. (It was $250, I would rather spend that to find out that the idea is silly than the $1,600 for the 36v 800A.)

The whole concept is only a thought experiment at this time as I am still building my DC truck, though I have all the parts for the AC build.

Thoughts, ideas, derision?


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## dcb (Dec 5, 2009)

mostly derision  there are AC kits now and up to 1200v 1000 amp igbts often for less than $50 apiece.


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