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Thread: Novak Hv......77,280 Rpm..????

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  1. Novak Hv......77,280 Rpm..???? 
    #1
    Join Date
    03-04-2003
    Location
    ny/conn
    Posts
    120
    the latest ad for the HV states that the KV rating is(will be) 4,600 rpm/volt AND that it will run on anywhere from 10 to 14 cells(12.0 to 16.8 volts)........unless i'm doing something wrong, my math(16.8 x 4,600) comes out to the(potential) for 77,000+ RPM.....not too shabby.......
     

  2.  
    #2
    Join Date
    05-14-2003
    Location
    Portland, OR
    Posts
    611
    Remember that that number will be an unloaded number. Under load it's probably closer to mid 60K range, which still isn't bad.
     

  3. When will we see it 
    #3
    The main question on the motor is, WHEN will we see it out? I am patient, but the season is starting here and I need something for my one electric truck, and hate to go out buy a Hacker or others (knowing they might be faster) when the Novak seems to be so close. I have the SS system in the car and like it, not the fastest, but a lot of fun and good run time.
     

  4.  
    #4
    I may buy one. But I already have the Hacker C50. I hope this thing doesnt sell. Otherwise Brushless will not be so special.
     

  5. Hope it sellls well 
    #5
    I hope the system comes out and sells well. Now just what makes a brushless special, NOTHING, it just makes it easier for people that want to get into electric to get into it with out having to maintain as much, and get some more performance and runtime. The problem right now with the controllers is plain stupid. You only have a few companies making what will handle in a big truck and I am in hopes that Novak will make something that will hold up and not smoke under load. There is nothing special about Hacker, except for you can't find a good controller to run it, even Hacker knows it, that is why they say it will be 6 weeks or more before something is imported that they HOPE will work on it and stay together. Maybe it will also bring the prices on them down, which would be great too.
     

  6.  
    #6
    Join Date
    03-04-2003
    Location
    ny/conn
    Posts
    120
    NOVAK's got alot of folks on edge(and they know it)..........i've had the 5800 in my xxxt for quite some time now. i race with it over the summer season and it's held up real well and has made the car very competitive....it's nice not to have to maintain the motor so that i can direct all of my efforts to the rest of the car(bearings, diff, clutch, alignment, etc). want to do the same thing with my E-MAXX.........it requires alot more mtce(cvds, bearings, alignment, etc). also like that the NOVAK won't need an outside power source for the ESC........
     

  7.  
    #7
    Holy Cow! Really? It's that high rpm/volt!!! With that kind of rpm, I would only use 12-15 teeth pinions on my Emaxx. This motor is a lot hotter than the Hacker C50 maxx motor.

    NOW, we're talking speed here. Just a tad slower than my Lehner XL5000 (which by the way hits 40 mph with a 12 tooth pinion)

    I'm impressed..
     

  8.  
    #8
    Join Date
    03-04-2003
    Location
    ny/conn
    Posts
    120
    check out the NOVAK add in the latest RC DRIVER(page 15)....you'll see those "specs"/////////.i'm still waiting for NOVAK to get back to me in connection with them..............
     

  9.  
    #9
    Join Date
    09-15-2003
    Location
    Somewhere out there(Australia)
    Posts
    129
    but would you consider for example a supersport 5800 to be faster than a lehner basic 5300??? i have never seen a lehner run but from what i have read around i thought the lehner was faster... rpm/volt may not be the only thing that determines performance...
    error 404: sig not found
     

  10.  
    #10
    Well, the reason lehner 5300 is so much faster is because you can run so much more voltage throguh it.
     

  11.  
    #11
    Heres a Comaprison on 7 cell 3000. Please note I take NO credit whatsoever for this, I noticed it on a forum posted by
    Kraeuterbutter

    Kontronik Twist4200

    highest speed in km/h -- 38.6
    average speed in Km/h -- 16,9
    drivetime in minutes -- 7:45
    distance driven in km -- 2,16
    Temp of motor in C -- 28
    Temp of controller in C -- 30
    Temp of batts in C -- 44

    Lehner Basic4200

    highest speed in km/h -- 36.8
    average speed in Km/h -- 17,9
    drivetime in minutes -- 7:27
    distance driven in km -- 2,15
    Temp of motor in C -- 37
    Temp of controller in C -- 34
    Temp of batts in C -- 46

    Novak SS5800

    highest speed in km/h -- 39.7
    average speed in Km/h -- 17,3
    drivetime in minutes -- 8:09
    distance driven in km -- 2,3
    Temp of motor in C -- 10
    Temp of controller in C -- 32
    Temp of batts in C -- 46
    "blue is better but purple is the best"
     

  12.  
    #12
    Join Date
    05-14-2003
    Location
    Portland, OR
    Posts
    611
    Well, the reason lehner 5300 is so much faster is because you can run so much more voltage throguh it.
    Well, that is one reason. But a Lehner 5300 is still faster than a Novak Super Sport on 6 cells.

    The reason is that the lehners RPM per volt is rated under load while the Novak is rated unloaded.

    This means that in the car the Lehner will pull 5300 RPM per volt, where as the Novak will only pull around 4400-4500 RPM per volt. That's a pretty big difference overall.
     

  13.  
    #13
    With no load, the SS5800 is 5800 rpm/volt. The Basic 4200 is just a touch more than 4200 rpm/volt. The rotor diameter of the basic series motor is much larger than a supersport. The supersport rotor diameter is more like a 400 series motor while the basic is a 500 series motor. As a result, the 5800 will bog down more under load than a Basic motor. When I hooked up a propeller to a 5800 motor under 7.2 volts, it was sucking up over 50-60 amps and spinning at 15000 rpm. Under that load, the voltage was down to 4.0 volts. The Basic 4200 was spinning at 20000 rpm!!!! It was drawing more current, but the fact of the matter is that the Basic 4200 is faster than a SS5800 under severe loading.
     

  14. no load. 
    #14
    If Lehners motors were rated at RPM/V under load, wouldn't they post what type and weight the load was equal too?????

    I do not think the rating is under load. Please find me a reputable source(preferbly by Lehner themselves) that state the rating is under some type of "load"....
     

  15.  
    #15
    RPM/Volt does not change under load. It is a motor constant. Novak's ratings don't make a lot of sense. Unless there is something strange going on inside the sensored controller, if the motor has a kt of .45 in-oz, then it is roughly 3000 rpm/volt. How can the 4300 and 5800 have the same kt? Kt is directly proportional to rpm. The 5800 will have a lower kt than the 4300. I've seen the Basic 4200 and Novak 5800 in similar trucks on the track together, and the Lehner is a much stronger motor.......750W vs <200W. The Lehner can produce a lot more torque.
     

  16.  
    #16
    Join Date
    12-16-2000
    Location
    Harrison, OH
    Posts
    1,307
    How do you figure that torque and rpm have to be proportional?
     

  17.  
    #17
    That's just the way electric motors work.....the kv is inversely proportional to the kt. It is a set relationship like P=VI. kv = 1355(?)/kt
     

  18.  
    #18
    RPM/V does change depending on motor load. Being a little overgeared, would drop the rpm/v considerably.
     

  19.  
    #19
    You are mistaken. The rpm/volt is not changing in your example, just the final rpm of the motor The motor draws more current dropping the voltage from the batteries. As a result the final rpm drops, however the kv has not changed.
     

  20.  
    #20
    Quote Originally Posted by starluckrc
    You are mistaken. As a result the final rpm drops, however the kv has not changed.
    Like I said. RPM/V goes down. Only in a perect world, the motor wont be taken by drivetrain load, therefore being able to hold its RPM/V rating.

    Again, no one has proof whether or not the motors RPM/V rating is done under a load or not. None of my motors(brushed or BL), have ever reached a manufaturers RPM/V rating while under any load.
     

  21.  
    #21
    Join Date
    06-05-2003
    Location
    Taylors Falls, Minnesota
    Posts
    1,123
    mtrsprt, it's a matter of physics. Starluckrc knows what he is talking about.
     

  22.  
    #22
    I so can clearly think, that if I put 14.4V to a 3100 rpm/v motor, the motor will be spinning @44,640rpm, or vey close to that in an E-maxx under load?

    I still highly doubt it. We need FACTS here, not speculation. Whether he knows what hes talking about or not, there hasn't been any manufacturer stating whether the motor is under load or not, while figuring the rpm/v specification.
     

  23.  
    #23
    Given the E-maxx's final drive ratio of 17.9:1 in 2nd gear, then if the Lehner XL3100 will do 44,640rpm with 14.4V feeding it, then you could say the E-maxx will reach 42mph. Correct??? I haven't seen anyone with a motor that has only a 3100rpm/v rating push an E-maxx to 42mph on only 12 cells.
     

  24.  
    #24
    Join Date
    06-08-2003
    Location
    Austria, neart Vienna
    Posts
    66
    Lehner specifies the load where the motor should reach a certein rpm/v number.
    e.g. my Basic 4200 ist rated 4200rpm/V @ 40A (stated on the specs sheet)

    also note:

    Code:
    Spann.	Strom	PEing.	Drehz.	Moment	PAusg.	Wirk.
    Volt	Amp.	Watt	U/Min.	Ncm	Watt	%
    
    6,62	7,90	52,3	30003,7	1,07	33,8	64,6
    6,62	8,24	54,6	29961,7	1,14	35,7	65,4
    6,61	8,36	55,3	29959,1	1,17	36,7	66,5
    6,61	9,76	64,5	29806,4	1,47	45,8	71,0
    6,61	12,16	80,4	29514,5	1,98	61,1	76,0
    6,61	14,10	93,2	29290,9	2,40	73,7	79,1
    6,61	15,68	103,7	29123,7	2,75	83,8	80,9
    6,62	18,85	124,8	28781,6	3,42	103,2	82,7
    6,63	21,67	143,8	28500,4	4,01	119,6	83,2
    6,64	25,57	169,9	28120,3	4,84	142,4	83,8
    6,64	28,36	188,4	27864,8	5,44	158,7	84,2
    6,65	31,17	207,4	27619,6	6,06	175,2	84,5
    6,67	34,24	228,5	27367,3	6,69	191,6	83,9
    6,67	36,66	244,6	27088,6	7,25	205,5	84,0
    6,67	39,05	260,6	26806,9	7,77	218,1	83,7
    6,66	42,26	281,6	26455,8	8,47	234,5	83,3
    6,66	45,25	301,5	26128,2	9,13	249,8	82,9
    6,67	47,91	319,7	25872,0	9,70	262,8	82,2
    6,68	50,80	339,5	25582,1	10,33	276,8	81,5
    taken from www.lehner-motoren.com

    the data suggests that the motor will reach ~4000rpm/V @ 40A

    Only such detailed data can give you a hint of what a motor is capable of or how it will perform under certain conditions.

    Novak only stated the data to compare it to an (on the paper) "inferior" 10 turn brushed motor in the same paragraph.
    Funny that any decent 10t blew the SS5800 away in several tests...
    So "kv" and "kt" is much too theoretical to give an accurate impression for rc use.

    Also dont mix kv (a constant theoretical motor specific value) with rpm/V @ I (a measured value) and please note that no Basic 4200 will give you 750Watts @ 6 cells, or do you have cells that could supply more than 150A?
    The Basic will reach the 700W range towards the upper max. of it's rpm range, that means you'll have to use 12 or even more cells.
    And even then, this power can only be achieved for short bursts, or can you imagine a 140gr. motor making 1Hp for a complete runtime.
    I do not want to say that the 750W is crap, it rather shows that the motor is able to draw some serious current wich will build up the torque and explains the great acceleration of this motor.
    But that doesn't mean that you should gear it low to have it constantly draw so much current.
    Last edited by re-inferno; 07-17-2004 at 06:11 AM.
     

  25.  
    #25
    Why doesn't the site you posted list the XL motor specs?

    Seems like they had the basic 4200,and 5300, together will the XL2800,3100,3600

    Are there really any differences in the "basic" and the XL series, or are they both truly the same series????
     

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