Lehner vs Plettenberg

[kufman]

Hello all. I had a little fun and compiled some of Lehner's data on their basic series of motors and some of Plettenberg's info on their Extreme and Shadow series. The first picture shows the normalized RPMs, or in other words the RPM/V of each motor plotted versus current. No big surprises here. The shadow is the fastest, then the 5300, then the extreme, then the 4200. The second picture is the efficiency. Kind of interesting to note that the Pletty's are more efficient. When I get the time I will make a picture of the torque of each.

[kufman]

second picture

[Craps]

Thank you and I am looking forward to those torque graphs that has me really interested since the Extreme has way more torque than the 5300 or 4200 with my on track comparision of the 3 motors I own. You have me interested in the Shadow now that I seen those rpm numbers, but it maybe too much to hook up on the dirt.

[kufman]

I have found that the basic 4200 is a lot to put down on the dirt so I can't imagine what it would be like to try and use the Shadow on the dirt. I think you have the best motor for the dirt already.

[kufman]

Here is the torque graph. The extreme and the 4200 appear to be very close to each other. The number on the right is the torque divided by the current to get the Kt constant. I averaged them over all the points and I got the following

Shadow: 0.139979344 N-cm per Amp
Extreme: 0.194662044
4200: 0.179732308
5300 0.155681879


According to my conversion you would multiply these numbers by 1.4161 to get the equivalent in american units (In-Oz per Amp). I might have messed up since that would only make the Extreme a 0.2757 In-Oz/A. I think novak quotes 0.45!! Although I know novaks Kv rating is a little off so maybe the Kt rating is too. Somebody correct my converion if I did it wrong.

[starluckrc]

That's the same conversion factor I use. Novak claims .45kt for both of it's motors so it has to be a function of the controller and sensored setup. kt=1345/kv. You can't go by torque constants alone, because a little B20-31S will have about the same kt as a B50-8L, but the 8L handles a lot more current, which helps it produce a lot more torque.

The Pletties not only have an edge due to higher efficiency (more out for same input), but also in driveability with the 4-pole design based on experience so far.

[kufman]

Ya I have noticed that my 4-pole aveox has a very smooth startup. My opinion is that due to be 4-pole the controller is getting twice as many "sensor" inputs per revolution. By sensor I mean signals via the unused coils producing an induced current. Since it is getting more inputs, it takes fewer revolutions to aquire the rotors true position.

I am hoping to get an Eagle Tree system for the holidays (I don't know that everyone here is of the same religion so i will keep it generic). With it I will be able to make my own rpm and current measurements since the box can be used as a real time input to a computer using the USB cable. Add to that a slave motor (most likely my Feigao 10L) with a full wave rectifier on the output wires, I will be able to make a linear current ramp. A simple integrator will vary the drive to transistors that will provide a load for the slave motor. Using the eagle tree system I will be able to measure the rpm and current on DUT (device under test). This should provide a reasonable RPM vs current comparison between the motors I own (Aveox, basic 4200, Shadow(soon), novak 5800). I can actuallly measure the current now since I bought some 50A hall effect units, but I don't have a good way to measure RPM and no way to automatically log it into a computer.

[Craps]

Maybe this is dumb question, but why does the Plett graph lines appear to be shorter on all graphs than the Lehner motors?

Is it due to fewer numbers from Plett compared to more information inputed on the Lehner motors?

Looks like the Pletts have shorter power bands by the graphs?

[kufman]

Ya the Plett data sheets had a shorter current range. They tend to start at 20 or 40 amps and go up to 50 or 60A. The lehner data sheets usually started really low, almost no load low. I have the sneaky feeling that the Pletts may be really innefficient at low currents. I know my aveox with no load will get hot to the touch in less than 10 sec, even at partial throttle.

[Craps]

So interpeting the info from the graphs between the 4 motors since I own 3 of the 4 that I now need to buy a Shadow motor for more straight a way speed unless I can keep going up on the pinion size of the Extreme until I am beyond the superior effiencincy of the Extreme to equal what a Shadow has down the straight a way, but still have the torque to come of the corners faster. Heat will be my enemy!

[kufman]

Yes you will have to be careful. I geared my basic 4200 at 5.45:1 in my sedan in an attempt to keep up in open modified class. I used a fan on the U-force and things went well, except the one guy with the 8T brushed was still a little faster in the straights. The shadow should fix this problem.

[havy]

Starluck, will you be carrying the Plett. shadow?
I'm interested...

havy

[Craps]

Yea Jamie
You better save me one too so I can say I have all 4 motors.

[starluckrc]

I will have the Shadow, Extreme, Maxximum, and BigMaxximum. Any other Pletty can be special ordered as well.

[SpEEdyBL]

Hey Kufman, at what voltage was the rpm graph tested at? I entered the data of the lehner motors into my graphing calculator, and with a linear regression model, the 4200 reaches 0 kv at about 285 amps and the 5300 reaches 0 kv at about 320 amps. Thats way more amps than I ever seen a brushless motor pull before, so I'd like to know the voltage. (maybe the graph suddenly drops off though) Different voltages will result in a different graph possibly.

[Chase023]

How much for a Maxximum with the fan? Availability?

[kufman]

I used the 6V graphs for the lehner motors and the 7 volt graphs for the pletty's. The reason being is that the 6v graphs from lehner were voltages like 6.7x and the 7 volt graphs for pletty's were like 6.7x. they just call the same voltage range by different names.

I am planning to make my own test of brushless motors and instead of starting at no load I want to start at 0rpm and let them acclerate while putting a constant 40A load on them. this will not happen for a while since I will need my Eagle Tree system to do it.... which i don't own yet.

[e_lm_70]

I am planning to make my own test of brushless motors and instead of starting at no load I want to start at 0rpm and let them acclerate while putting a constant 40A load on them. this will not happen for a while since I will need my Eagle Tree system to do it.... which i don't own yet.

You are the Man !

This is what it is needed to be seen : how the hack the BL motor are working with efficiency % from 0rpm.

The rc cars application needs power (or better torque) and efficiency for a wide range of of RPM.

So if you can get out some power and efficincy curves starting from 0 rpm it will be a real achivement !

e_lm_70

[SpEEdyBL]

at 0 rpm a motor has 0% efficiency.

[kufman]

Yes but it does have a stall current and a stall torque.

[Craps]

Been talking to Jamie about the U-Force 75 and the Plett Extreme on 11.1 volts maybe the hot ticket for my T-4. I think I am going to try it tomorrow at the track to get ready for our 40 minute main race coming up.

[kufman]

I just got my Shadow today and from running across my living room I think this thing is going to be great. I hope to go to the carpet track tomorrow so I should have better info after tomorrow.

[Craps]

Living Room testing usually leads to a sleepless night going to bed all excited about going to the track the next day. Usually living room testing is not successful until you break something or drive the dog crazy. :D :D

Good luck at the track!

[DaFF]

Ha Ha Ha good one Craps !

DFF

[kufman]

Living room testing drives my cats nuts and does deprive me of sleep. I didn't break anything.... but I did come close. Today I go to the track with the Shadow in the TC3, the Novak in the RC10L3 Touring, and a piece of junk 19T in my 1/12th scale. Should be a fun day. ( I have run the 10L3 Touring on a Basic 4200 and it was awesome!!)

[Simen123]

Let us know how your shadow is doin` :)

[Craps]

I now own all 4 motors since Jamie delivered the shadow to me Sunday. Now I need time to track test it.

[OptimaMan]

SO, how does it compare?????? I don't want to analyze the charts or what - those charts could be done through different conditions, controllers, etc. How's it really run? Does it make the car insanely powerful? I don't care for smooth revving power. I want massive torque and uncontrollable power - I wan't people's eyes to pop out and jaws to drop - even from guys who have ultra powerful gas models. I want it to through dirt rooster tails 50 feet long. :)

[666yeti666]

Hi Kufman, I'm very curious about the test results between the 5300 and the shadow. I'm doubting between these two types for my Evader truck. Any suggestions.
By the way I'm from Europe too; the netherlands

[kufman]

666yeti666,

The data that I show is from the manufacture's homepages. I personally own the basic 4200 and the shadow. The basic 4200 makes a good offroad motor and runs well on the Schulze U-Force 75 controller. The shadow is rather difficult to run on U-force unless you want to run a fan. I don't own the 5300, but I would guess that it would be between the 4200 and the shadow. Would probably run well on the U-Force and would probably generate a little more heat in the controller than the 4200 but less than the shadow.

OpotimaMan,

The shadow does not have insane power. It has a ton of rpm, but the torque isn't the high. I you want huge power, run something in the 4000-4500 rpm/v range on like 8 or 10 cells (or LiPoly).

[666yeti666]

Kufman,

I'm gonna run either of them with a BK micro1895, which has a heatsink mounted on top of the FET's so I don't expect any problems with heat.
Maybe the 5300 would be a good choice, it has better torque and proper topspeed than the shadow.
Do you have any tips for a good internet shop in germany for buying a Lehner ?

[studysession]

Here:
http://www.bk-electronics.com/catalog/index.php?cPath=35&osCsid=cb7ceef62af0d5085afaef3fcbd9529f

[SpEEdyBL]

Or here:
http://www.rc-monster.com

[666yeti666]

Thanks,
actually I wanted to order one directly at :
http://www.bk-electronics.com
So I sent them an email but never heard anything of them anymore !!
Strange, obviously they don't want to earn money ?

So I finally got to :
http://www.rc-motorradshop.de
I got a very friendly and nice email back, so just orderred one at those guys.

Now waiting for it to arrive .....

[rhylsadar]

hi
the evader is that duratrax offroad stadium truck kind of similar to the asso T4 right? for an offroad 10th application i would not consider between a 5300 and a shadow but more between an extreme and a 4200.
that the 18.95 has a heatsink does not mean that you will have no temp problems. most controllers used in car application have heat sinks. but still many of us are confronted with temp issues.
bye
rhylsadar

[studysession]

When ever I email BK to ask anything - sometimes it is same day response and other times it is more than a week for a response. Never know.

[666yeti666]

rhylsadar,
the evader is indeed an off road truck.
Why do you think the 4200 is a better choice ?
In fact I'm more concerned about the higher torque of a brushless setup in general, which most probably let the ball differential slip. (I would rather have had a truck with a GEAR differntial like a traxxas stampede/rustler)
About the temp problems, I only have experience with a brushless setup in an airplane, but can imagine that the current flow is much higher in a car setup, due to the mass that has to be moved during start up.

Do you know of any ball diff slip problems with a brushless T4 ?

[kufman]

If you adjust the slipper and diff correctly in the T4 you shouldn't have any problems. I have heard that traxxas products have trouble with idler gears in their trannies when used with brushless motors. I agree also that the Extreme and the basic 4200 are better choices for offroad stadium trucks. They have a better amount of torque and the RPM range is more practical that the shadow.

[666yeti666]

I agree that the 4200 or extreme have more torque, but if i choose a smaller pinion, than the "overall" torque should be increasing.
Also, when using the exact same setup, the topspeed with the 5300 is theoretically higher.

And I've had an Asso B4 before that I run with a triple 15 turn and I know that all parts are of very, very good quality, but sold it because of to less ground clearance ....

Anyway I already placed (and payed) an order for the 5300 so now I have to see how it works, sometimes theory and practice can be different ...