castle 4 pole series

[kaneohecrawler]

anyone used these yet/ mostly intrested in the 2400kv.. but was wantin to know how the low end on the 3800kv is?
any help would be greatly appreciated

[JohnRobHolmes]

Just got a box of these in and will be testing them. Low end on the 1406 is decent enough. The longer motors should have better startup torque, can't guess on how the detent torque will affect the startup speed.

[kaneohecrawler]

Originally Posted by JohnRobHolmes

Just got a box of these in and will be testing them. Low end on the 1406 is decent enough. The longer motors should have better startup torque, can't guess on how the detent torque will affect the startup speed.

Jus ordered a 35t from you on Saturday.. if you have the 3800kv 4pole or the 2400kv 4pole I'm hella intrested should be ready to purchase at the end of the week

Thx john its most greatly appreciated

[Meatwad]

I've got the Mmp/1415 combo in my slash4x4 on 2s (damn rules) and its awesome geared for the moon. Detent torque is crazy, can barely turn the tiny 1/8" shaft by hand. Should've left it 5mm IMO. I'm happy with it and been curious how it'd be in my 2spd scx.

Its my understanding that detent torque is not directly related to motor torque. How much truth is there?

[92LILREDYJ]

I have the 2400kv in my emaxx, I play around on the slow end, and on some rocks. It crawls really good.(for a bl emaxx lol) Lots of low end and startup seems good.

[JohnRobHolmes]

Originally Posted by Meatwad

Its my understanding that detent torque is not directly related to motor torque. How much truth is there?

That is correct, if we can assume that it is only steel concentration or shape that is changed to affect detent and that these stator changes do not affect efficiency. In reality, changes in detent torque are normally caused by designs that do relate to motor torque. We can ignore a change from slotless to slotted design here, as there will be an increase in detent going from slotless to slotted and the peak torque will also increase.

For example, a motor that is twice as long will exhibit twice the detent of an "example" motor. It will also have twice the peak torque. I would consider this a second level effect. The detent torque is not driving the peak torque increase- it is the increased motor length.

Another example, if we skew the rotor to reduce detent torque the peak torque of the motor will not change directly, but the efficiency will take a hit and reduce peak torque accordingly. Skewing creates inefficient zones on the leading or trailing edges of the fields and is typically a last effort method.

The one way to change detent torque that DOES affect peak torque is the magnet field or air gap when a motor is run near magnetic saturation. If we weaken the field interaction (weaker mags or larger gap) we will reduce peak torque of the motor, but it will also increase low load efficiency and decrease high load efficiency. An example of this would be a change in rotor size or magnet strength.


I got to see some prototype ROAR motor simulations that had some insane detent torque because of the stator shape. It was so high that sensors HAD to be used to start up the motor, sensorless just couldn't move the rotor enough to get a bead on the positioning. They also had really high peak torque estimations, but it was because of the high efficiency of the design and not directly because of the detent.

[kaneohecrawler]

Thx guys for the help. I'm gonna be running the 3800kv on 3s jus gear down with a 13t pinion.shouldnt have any heat issues with gearing that high...

Thx john for super indepth explination.

[Meatwad]

x2 thanks JRH. kaneohecrawler let us know how it goes. I'm thinkin of tossing my 1415 in my scaler even moreso now

[NGreen]

JRH...thoughts on running more than 3s on a 3800? The limit is 3s but that is for heat issues built around a backyard bashing truck as well as a short course truck running near max rpm constantly. In a crawler with temps more manageable at lower speeds, do you think you could get away with a 4s or 5s pack?

[kaneohecrawler]

Originally Posted by Meatwad

x2 thanks JRH. kaneohecrawler let us know how it goes. I'm thinkin of tossing my 1415 in my scaler even moreso now

Will do I think ur 1415 should work even better bein its a 2400kv motor should work well I'm goin with the 3800kv geared down substantually... but ill be sure to keep this updated.

[kaneohecrawler]

Well I got the motor from a guy localy here on the island.. only has 1 run on it so should be fine still need to aquire a mamba max pro so can set mah drag brake and mess with startup power n such ill keep posting on my findings.. he has a 13t on the motor already so torque should be good. We shall see about the wheelspeed side.

[KBrog]

I use a 3800kv 4pole in my HPI mini trophy truck. The start up torque was so moch I had to reduce in the ESC by 50%. After I did that it runs great. I had a 5700kv with a 12t pinion in it first. It ran hot. The 3800kv with a 18t pinion has the same performance/speed, and runs cool.

[mrG]

These are non sensored, right?

[kaneohecrawler]

Originally Posted by mrG

These are non sensored, right?

That is correct non sensored.. I'm gonna run a very small pinion ie 15 or less to reduce any chance of cogging on start up or when accending a steep climp with low wheel speeds.