openinverter forum

I'll be posting a video soon but with the inefficient setup in the photo I was able to set the current to 3A @ 36V and the power steering worked fine. When turning the wheel the current rose to 6 or 7A but fell back to 3A immediately.
I say inefficient because an alternator is not efficient as a motor. I suspect a suitable motor could bring the current drain down to between 3/4 and 2/3 of these figures and the ebike controller I used is the cheapest available so not efficient either.
The one caveat to bear in mind is there is no weight on the front of the car so I suspect a completed conversion will draw more current when turning the wheel than it is now. The other thing is the ebike controller was not trying to maintain the speed of the motor, it was only trying to maintain the throttle position so a better setup might draw significantly more current when turning the wheel.
However it proves that this is a possible solution and if you choose your motor and controller correctly I see no reason why ac couldn't be incorporated.
Whether it would make more sense to source a 12V motor suitable and drive it from the 12V system or go with a totally separate high voltage system like this one I'll leave you guys to decide.

Here you go guys.

Alibro wrote: ↑Sat Jan 02, 2021 7:40 pm Here you go guys.

Really good solution. Now considering 8A x 36V is around 300W. It is not bad at all. Considering my pump pulls 55A on full load and that is 700W!

Can you give alternator 14V excitation and tell me how it works with it? You know, if we could just use normal 14V from a car.

Tnx

arber333 wrote: ↑Sat Jan 02, 2021 8:39 pm

Alibro wrote: ↑Sat Jan 02, 2021 7:40 pm Here you go guys.

Really good solution. Now considering 8A x 36V is around 300W. It is not bad at all. Considering my pump pulls 55A on full load and that is 700W!

Can you give alternator 14V excitation and tell me how it works with it? You know, if we could just use normal 14V from a car.

Tnx

For an alternator to work as a motor you need to remove the diodes and voltage regulator, then to drive it you need a 3 phase motor controller that works without hall effect sensors. If you can find one that works with 14V then go for it but there are probably better options out there.

arber333 wrote: ↑Sat Jan 02, 2021 8:39 pm

Alibro wrote: ↑Sat Jan 02, 2021 7:40 pm Here you go guys.

Really good solution. Now considering 8A x 36V is around 300W. It is not bad at all. Considering my pump pulls 55A on full load and that is 700W!

Can you give alternator 14V excitation and tell me how it works with it? You know, if we could just use normal 14V from a car.

Tnx

For an alternator to work as a motor you need to remove the diodes and voltage regulator, then to drive it you need a 3 phase motor controller that works without hall effect sensors. I'm not sure there are any that will work with 14V but there are probably better options out there.
I happened to have the alternator motor and ebike controller handy so that is what I went with.

Alibro wrote: ↑Sat Jan 02, 2021 9:05 pm For an alternator to work as a motor you need to remove the diodes and voltage regulator, then to drive it you need a 3 phase motor controller that works without hall effect sensors. I'm not sure there are any that will work with 14V but there are probably better options out there.
I happened to have the alternator motor and ebike controller handy so that is what I went with.

I know about using alternator as motor, but havent tried yet myself. Would you try feeding 12V to the rotor instead of 5V like you are doing on the video. How would the alternator behave then? would there be more losses?

arber333 wrote: ↑Sat Jan 02, 2021 9:26 pm

Alibro wrote: ↑Sat Jan 02, 2021 9:05 pm For an alternator to work as a motor you need to remove the diodes and voltage regulator, then to drive it you need a 3 phase motor controller that works without hall effect sensors. I'm not sure there are any that will work with 14V but there are probably better options out there.
I happened to have the alternator motor and ebike controller handy so that is what I went with.

I know about using alternator as motor, but haven't tried yet myself. Would you try feeding 12V to the rotor instead of 5V like you are doing on the video. How would the alternator behave then? would there be more losses?

There is no need to put 12V to the alternator as it works OK at 6V but If I decide to stick with this solution I'll try different voltages to the rotor. It would just mean turning the dc motor controller to 33 percent instead of 17 to get 12V but I would need to watch the temperatures as the rotor could get hot at 12V since the regulator has been removed.

The alternator should require less stator voltage to reach the same speed when the rotor winding is given less voltage. Same thing that field weakening tries to do in PM motors, just a lot more obvious.

Based on the voltages on the video and the apparent ease the alternator can turn the pump with, I'd say 14V to the stator might just be able to give enough speed and torque, given the appropriate rotor voltage.

You're probably right but I don't have a controller that will work at 12V - 14V. The one in the video cuts out below 32V.

Generally, supplying more than about 6V to the rotor does not increase flux since it's saturated about that point.

Isaac96 wrote: ↑Sun Jan 03, 2021 4:13 am Generally, supplying more than about 6V to the rotor does not increase flux since it's saturated about that point.

That's been my experience however reducing the voltage a little might be an option.

I just watched a video on Youtube where a guy put a Mini Cooper electric power steering pump into his Hot Rod. ​
This is interesting enough but while reading the comments he mentioned at one point he changed the fluid to normal power steering fluid and the pump started drawing crazy current. When he put in fluid that was correct for the mini the problem stopped.
The reason I found this so interesting is my Zafira pump went mad drawing crazy current and I was using standard power steering fluid.
Could it be the problem was the fluid I was using? Unfortunately my EPAS pump met with an accident involving a soldering iron being accidently turned on so unless I buy another I won't be able to test this.
Of course I have just started building a mounting bracket for the Ebike/Alternator setup mentioned earlier.

Here is the video.