information on kb45 motors? - Page 3 - RC-Monster Forums

scarletboa · 12:57 AM

my KB45-8XL separated the rotor from the shaft, so i ground down the shaft on my KB45-12L 1400kv motor and threw it on my savage. the run lasted about 6 inches as my EZrun 150a smoked itself....the only setting i changed on it was turning the LVC off. i was using a lipo monitor that plugged into the balance lead on the lipos, because the stock setting of 3.0v was too low. i had done it manually as i didn't have the program card at that point and i might have messed something up in the programming in the process of turning the lvc off.

BTW: i was running 2 3s packs in series.

Nixpus · 09.18.2009, 04:42 AM

Will be testing the KB45-08XL in a converted savage soonish... on 6 cells of course. 35k rpm sounds pretty reasonable.

_paralyzed_ · 09.18.2009, 05:44 AM

Quote:

Originally Posted by Nixpus

Will be testing the KB45-08XL in a converted savage soonish... on 6 cells of course. 35k rpm sounds pretty reasonable.

I smoked mine in 5 minutes on 6s in an e-maxx. agwut has a lot more experience than anyone with kb45's and he recommends 25k rpm.

Whatever you do, keep watching the temperature.

aqwut · 12:41 PM

Quote:

Originally Posted by _paralyzed_

I smoked mine in 5 minutes on 6s in an e-maxx. agwut has a lot more experience than anyone with kb45's and he recommends 25k rpm.

Whatever you do, keep watching the temperature.

yeah, I know for a fact..
the 1700KV one runs awesome on 4S..
the 1000KV one runs awesome on 6S...
and the 700KV one runs awesome on 8S...

So they're are all about 20-25K range...
You could run them all day long with a heatsink and/or fan...

The ones that died on me where running about 40-45K rpms.. They don't seem to mind the amp draw, they just don't like the RPMS...

My favourite is the 1000KV, insane for showing off on 8S.. 700KV same thing on 12S...

aqwut · 09.18.2009, 12:41 PM

Quote:

Originally Posted by Nixpus

Will be testing the KB45-08XL in a converted savage soonish... on 6 cells of course. 35k rpm sounds pretty reasonable.

I would use the 1000KV for 6S and just gear it higher...

scarletboa · 09.18.2009, 07:30 PM

i think the 1200kv would be better for 6s. that's less than 30k rpm. my 8xl (1600kv) ran 140-150F whenever i ran it with 85F ambient. that was with a stretched traxxas heatsink and the kershaw motor mount. that was on 6s with a $27 plane speed control. the hottest i temped it at was 160F after a 10 min. run with the gear mesh WAY too tight due to the motor mount shifting. it ran around 145F most of the time during my street bashing.

aqwut · 09.18.2009, 10:36 PM

Quote:

Originally Posted by scarletboa

i think the 1200kv would be better for 6s. that's less than 30k rpm. my 8xl (1600kv) ran 140-150F whenever i ran it with 85F ambient. that was with a stretched traxxas heatsink and the kershaw motor mount. that was on 6s with a $27 plane speed control. the hottest i temped it at was 160F after a 10 min. run with the gear mesh WAY too tight due to the motor mount shifting. it ran around 145F most of the time during my street bashing.

Awesome.. glad it worked for ya.....

scarletboa · 09.19.2009, 12:14 AM

Quote:

Originally Posted by aqwut

Awesome.. glad it worked for ya.....

yeah, until the rotor separated from the shaft. that happened one run after i put loctite on the endbell threads, so now i can't get it open.

i can't say anything about the 1400kv L length motor yet, but i hope it works well once i get my EZrun back from nitrorcx.com..

Nixpus · 09.19.2009, 04:26 AM

At the moment my savage is powered by a Hobbywing 4465... its way too powerfull for the truck.

Was hoping the KB45-08XL would be easier to controll. However, when I read Scarlets conversion thread it seems like its just as impossible as the 4465 :)

If 25K rpm is the limit for the KB's then the 10XL sounds just about right - 26.600 on 6 cells.

Will a lower KV motor be easier to controll (wheelie/backflip wise) or will the increased torque mean that it wheelies more. I mean if I geared for about 45mph will a 1200KV motor then be easier to handle than a 2000KV? And why?

aqwut · 09.19.2009, 11:09 AM

Quote:

Originally Posted by Nixpus

At the moment my savage is powered by a Hobbywing 4465... its way too powerfull for the truck.

Was hoping the KB45-08XL would be easier to controll. However, when I read Scarlets conversion thread it seems like its just as impossible as the 4465 :)

If 25K rpm is the limit for the KB's then the 10XL sounds just about right - 26.600 on 6 cells.

Will a lower KV motor be easier to controll (wheelie/backflip wise) or will the increased torque mean that it wheelies more. I mean if I geared for about 45mph will a 1200KV motor then be easier to handle than a 2000KV? And why?

25K is not the limit, I have ran the 1700KV motor on 8S, and it was insanely fast... I recommend somewhere around the 25K mark.

Example, 1200 KV and 2000 KV motors of the same size.. Powering a Monster Truck...

They both have the same power output.. with the lower KV you have to gear higher and use more voltage, and with the higher KV you'd have to gear lower and use less voltage.

I prefer to use lower KV and higher voltage & less RPMS.. but there is a limit..

Lower KV motors can't take as much amps as the higher KV.. the Lower KV relies more on Voltage.. whereas the Higher KV motors relies on Current. know what I mean?

Nixpus · 09.20.2009, 05:48 AM

Yep in order to get the same amount of power (watt) Id have to increase the voltage on a low KV motor, since it have more windings/turns and thus draws less amps.

This also ansvers my question. With the same voltage available the low KV motor should be easier to handle - if geared for the same top speed - since it will have a lower power output. Cheers... KB45-10/11XL here I come :)

sikeston34m · 09.20.2009, 07:00 AM

Quote:

Originally Posted by aqwut

25K is not the limit, I have ran the 1700KV motor on 8S, and it was insanely fast... I recommend somewhere around the 25K mark.

Example, 1200 KV and 2000 KV motors of the same size.. Powering a Monster Truck...

They both have the same power output.. with the lower KV you have to gear higher and use more voltage, and with the higher KV you'd have to gear lower and use less voltage.

I prefer to use lower KV and higher voltage & less RPMS.. but there is a limit..

Lower KV motors can't take as much amps as the higher KV.. the Lower KV relies more on Voltage.. whereas the Higher KV motors relies on Current. know what I mean?

Hi Aqwut,

How about a KB45 10xl in an E Revo?

Let's gear it 20/40 using mod 1 gears, then put in on 6S with a MMM ESC.

How do you think this setup will do, according to your experience with the KB45?

Geared for 44mph according to BG's speed calculator, and spins up to 26,640 rpms.

Also, Where can I find a heatsink/fan for this beast of a motor?

aqwut · 09.20.2009, 08:25 AM

Quote:

Originally Posted by sikeston34m

Hi Aqwut,

How about a KB45 10xl in an E Revo?

Let's gear it 20/40 using mod 1 gears, then put in on 6S with a MMM ESC.

How do you think this setup will do, according to your experience with the KB45?

Geared for 44mph according to BG's speed calculator, and spins up to 26,640 rpms.

Also, Where can I find a heatsink/fan for this beast of a motor?

I think you have a solid (cheap $) setup there man... that should do you really good..... I use a 40mm x 20mm fan, and just zip tie it around the motor... 20/40 gearing comes up to only 36MPH.. for my revo 3.3.. Wouldn't you need 22/36 for 45MPH..?

and that motor is plenty powerful for that revo.. Awesome!

sikeston34m · 09.20.2009, 05:23 PM

Quote:

Originally Posted by aqwut

I think you have a solid (cheap $) setup there man... that should do you really good..... I use a 40mm x 20mm fan, and just zip tie it around the motor... 20/40 gearing comes up to only 36MPH.. for my revo 3.3.. Wouldn't you need 22/36 for 45MPH..?

and that motor is plenty powerful for that revo.. Awesome!

Thank you for your reply.

Here are the values that the speed calculator gave me. It LOOKS correct.........hmmmmm..........

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.8333333333333332
Other Ratio: 1
Spur Tooth Count: 40
Pinion Tooth Count: 20
Total Voltage: 22.2
Motor KV: 1200
Tire Diameter (inches): 5.75
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 2 : 1
Total Ratio: 10.4359 : 1
Tire Circumference (inches): 18.06 inches (458.83 mm)
Rollout: 1.73:1
Total Motor Speed: 26640 RPM
Vehicle Speed: 43.67 mph (70.15 km/h)
Effective KV Value: 1200
KT constant: 1.13 oz-in/A

The difference is probably in the transmission gear ratio.

aqwut · 09.20.2009, 07:19 PM

Quote:

Originally Posted by sikeston34m

Thank you for your reply.

Here are the values that the speed calculator gave me. It LOOKS correct.........hmmmmm..........

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.8333333333333332
Other Ratio: 1
Spur Tooth Count: 40
Pinion Tooth Count: 20
Total Voltage: 22.2
Motor KV: 1200
Tire Diameter (inches): 5.75
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 2 : 1
Total Ratio: 10.4359 : 1
Tire Circumference (inches): 18.06 inches (458.83 mm)
Rollout: 1.73:1
Total Motor Speed: 26640 RPM
Vehicle Speed: 43.67 mph (70.15 km/h)
Effective KV Value: 1200
KT constant: 1.13 oz-in/A

The difference is probably in the transmission gear ratio.

Oh you're right.. I misread, I just assumed that E-Revo means a converted Nitro to Brushless..