# AC50 and medium sized cars

5583 Views 11 Replies 6 Participants Last post by  JRP3
The AC50 seems to have the highest profile of the AC Motors but I read varying anecdotal reports of its capability around hills. Chinese BLDC motors are looking very promising as an alternative.

On my commute I have a hill climb that has to happen. My car is a BMW 318ti. I am doing all my calculations at the GVMR 1555kg just in case.
The hill is a 4.6 degree angle (8 percent incline). I have calculated this to require 30-35Kw, and as it is 2km I will need to hold this for 90 seconds. If I do 1:1 through a transmission to the 4.44 diff then 3000 RPM will do 80km/h - sounds perfect. (Side question: I haven't decided whether to modify the auto transmission or put in a two speed transmission yet, but understand the former may add significant losses - any idea how bad?).

Either way, is this motor up to it? The chart says it can do over 40Kw at 3000 and at that point still has its 150 maximum torque.
http://hpevs.com/Site/images/jpeg/power-charts/pdf/ac50_102v_650a_metric.pdf

However people quote 50kw as its peak performance. So is this graph all peak readings? If so, how long is it reasonable to expect a motor to operate at peak for? And what if one added a water cooling plate to this motor (and to the controller), what impact would that have?

Richard
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Hi,

I've put your datas in my calculator, and made a simulation with :
- 32Sx3P Calb-SE100AHA (25kWh usable 91kW max)

The results on flat ground :
- 137 km/h max
- 87 km
- 283 Wh/km

- 80 km/h max
- 42 km
- 576 Wh/km

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It depends

Since there is no indication of temperature rise of the motor for that dyno chart from HPEVS, it was likely a very short test of peak output and is fairly worthless for your evaluation. A duty cycle test with thermal profile is needed to characterize and rate a motor. Standard duty types for example include: S1 is continuous duty to reach thermal steady-state, S2 is short-term duty at a constant load with no thermal steady-state followed by a cool-down period (e.g. 10,30,60,90 min.), S3 is intermittent duty on-off where the starting current doesn't influence the thermal rise. S4, S5 ,etc... S8 is uninterrupted duty with periodic speed changes (closest to real life for EV). A good quality motor will have the duty cycle type, power, current, time, temperature rise, etc. listed on the name plate such that a usage determination such as you desire can be made. Doubt you will find S8, but S2 is common and would help answer your question. A cooling plate for motor and controller would certainly help in any situation.
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I don't think anyone has ever reported an AC50 getting warm enough to be a concern, and there is no way to effectively water cool it. The inverter is another story.
Hi Kennybody, thanks for your comment. In fact, this is just a single simulator based on motion équation.

But it gives you the time to reach the speed. Here 6 mn with 8° grade.

If the AC50 can stay 6 mn at full power it's ok, otherwise you have to reduce power.

It'll take longer, at a reduced speed, but safer.

The important thing is you can run an 8° grade, with a 1555kg car equiped with an AC50, and with care, as with an ICE car.
Hi
I really appreciate the responses and I've downloaded the calculator to have a play - is there an updated one with this motor in it, or do you just add in extra ones somehow?
I was more hoping that someone has had experience with this motor and can explain it's capability on hills and what the peak performance really means - ie. how long would I be able to drive with it at its peak before something bad happens, since I will need to hold that for about 2 minutes up the hill, or even longer if the peak arrives earlier and I have to go slower.
Richard
I have the smaller AC31 in a 2500lb Fiero and live in a very hilly area. For example from work to home is a 400ft rise over 3 miles, I've never seen elevated motor temps.

Cheers.
The AC50 seems to have the highest profile of the AC Motors but I read varying anecdotal reports of its capability around hills. Chinese BLDC motors are looking very promising as an alternative.

On my commute I have a hill climb that has to happen. My car is a BMW 318ti. I am doing all my calculations at the GVMR 1555kg just in case.
The hill is a 4.6 degree angle (8 percent incline). I have calculated this to require 30-35Kw, and as it is 2km I will need to hold this for 90 seconds. If I do 1:1 through a transmission to the 4.44 diff then 3000 RPM will do 80km/h - sounds perfect. (Side question: I haven't decided whether to modify the auto transmission or put in a two speed transmission yet, but understand the former may add significant losses - any idea how bad?).

Either way, is this motor up to it? The chart says it can do over 40Kw at 3000 and at that point still has its 150 maximum torque.
http://hpevs.com/Site/images/jpeg/power-charts/pdf/ac50_102v_650a_metric.pdf

However people quote 50kw as its peak performance. So is this graph all peak readings? If so, how long is it reasonable to expect a motor to operate at peak for? And what if one added a water cooling plate to this motor (and to the controller), what impact would that have?

Richard
I don't believe you stated at what speed you desire to climb the hill, unless you meant the 80 kph. I can tell you at 40 to 45 mph (67 to 75kph) it requires about 65Ah and about 6825Wh to climb 19 miles (32km) up a 4.5% grade in my about 2250 lb (1023 kg) Swift with an AC50, so about 359Wh/mile or 216Wh/km. It requires about 200A current and 21kW average power, and around 25 -30 minutes to reach the top. Motor temperature at top is about 55C in 70 F (21C) ambient, so about 1.06C/km temperature rise.

Now, make that a 3400 lb vehicle and 2 km long 8% grade and I would expect around 800Wh/mile and around 50kW power at the same speed, and about a 2*1.06*50/21 = 5C temperature increase. Peak shaft power of the motor with the 650A controller should be around 60kW with a 115V nominal pack. Hopefully this is within +/-30% of actual performance you would get, but no guarantees.
Thanks for this. Yes, would like to go 80km/h up this hill.
Now, make that a 3400 lb vehicle and 2 km long 8% grade and I would expect around 800Wh/mile and around 50kW power at the same speed, and about a 2*1.06*50/21 = 5C temperature increase. Peak shaft power of the motor with the 650A controller should be around 60kW with a 115V nominal pack. Hopefully this is within +/-30% of actual performance you would get, but no guarantees.
I think this part was mint for me . I will be running a 5.50-1 to a 7.30-1 gears in the car . But if you really think I should use the DC motor in my car .....well I guess ....OK . "But" , 200Ft lbs is great at 1500 RPM on built 5.0 H.O . My street racing engine only had 175Ft lbs at 1500RPM . And if that AC-76 set-up can do 8000+ RPM , I'm in heaven !!
Just remember there won't be much torque left around 8K RPM.
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