Yes, strange indeed, am still getting to grips with how the field weakening is instigated... Is it from when the back emf is a % of the pack voltage ?rstevens81 wrote: ↑Mon Jan 08, 2024 10:15 pm We are deffo getting a 1+1=5 with the voltages here...
The reason for the boost inverter is basically so the motor doesn't do field weakening, particularly the generator.
Based on the numbers so far you boost to 600v and you still have to field weakening to get it to 14k rpm top speed of the cars.
What I find strange is that if we feeding 1/2 of the voltage e.g. 650v/2=325v then we would expect that maximum rpm to be halved say 7+k rpm.
If it is indeed that the motors need 600v and field weakening then that could work to our advantage ... That would mean that motors are wound for torque and needs lots of voltage to get the revs through field weakening and boost, therefore welding the gears together might actually work.
But it basically going to come down to hard data with a matched inverter and drive unit to see what the feck is going on.
When the 14000rpm Mg2, was run unloaded, Mg1 at around 11000, was drawing 50A at 280v, which maybe say 10A to do the drivetrain friction, oil in diff swirling etc, and the other 40A into field weakening, in order to achieve around double the expected max rpm.