The power specification for the diesel engine is 45 kW @ 2200 RPM. An online calculator tells me that the torque is therefore about 200 Nm.
The weight of the tractor is about 2.7 tonnes.
Thinking about what motor to use, here are some considerations:
- The motor should be sealed against straw and dirt. Straw could be a fire hazard, and the motor will probably be open to the environment, which can be dirty. Water is a distinct possibility.
- The continuous rated power should be 40 kW or higher. Unlike most cars, tractors are sometimes used close to their rated power for long periods of time.
- Engine braking is essential. Tractor brakes are generally terrible, and operators rely on engine braking for safe operation on hills. Regenerative braking is the obvious way to make this happen.
- Throttle must control RPM. The tractor uses a hand throttle as well as a foot throttle. You set the throttle lever to a particular motor speed so that the implement is driven at a constant speed. Then you change gears to select your ground speed. So if you are driving under load, then push the clutch in and take the load off, the motor should stay at the same RPM (within reason). Regenerative braking should come into effect if the motor is driven faster than the set RPM, e.g. by driving down a hill.
- The typical motor speed will be 2200 RPM. This speed gives the PTO the standard 540 RPM.
- The battery voltage will be nominally 150 V. I have 48 LFP cells for this prototype.
40 kW @ 150 V = 270 A continuous. So a decent controller, but not over the top.
Any suggestions for a motor/controller for this application? In another thread Adverse Affects suggested the Emrax, although I don't know where I'd get one of those from, or how expensive they'd be.