3LikesTekin RX8 1/8 Scale Brushless ESC Thread
10-05-2010, 07:13 PM
#9631
What are the differences Between 4 pole and 2 pole?
10-05-2010, 07:20 PM
#9632
A little more info please? Steve you will love it!! that is a great motor for you with all the diferent tracks you go to. Tekin!!!!
10-05-2010, 07:33 PM
#9633
I know there is more magnets, but whats the real difference between 2 pole and 4 pole motors like power band torque rpms, lets say in the same kv which is more reliable, just general. Just seeing why tekin doesnt do both.
10-05-2010, 08:49 PM
#9635
4 pole motors make more torque at the expense of rpm.
Power is the result of torque multiplied by the rpm. These buggies need a lot of power to drive them, so you can either increase the rpm or the torque to produce more power (and then gear accordingly). In 8th scale we can run higher voltages at will to up the rpm, but it comes down to the motor's design as to its torque output. Going to a 4 pole motor provides a means to obtain extra torque and produces a cooler running motor with these heavy cars.
Most 10th scale motors are 2 pole with kv's starting at 2000 for a 17.5 turn all the way up to 10,000 for low turn mod motors. Being limited to 7.4 volts and a fixed motor design, more power can only be produced by gearing down and upping the rpm's on the motor. Also, simply being able to gear a motor correctly makes the 4 pole motors a better choice as most 2 pole motors can't be geared low enough in current 8th scale drivetrains to make up for their very high kv.
Power is the result of torque multiplied by the rpm. These buggies need a lot of power to drive them, so you can either increase the rpm or the torque to produce more power (and then gear accordingly). In 8th scale we can run higher voltages at will to up the rpm, but it comes down to the motor's design as to its torque output. Going to a 4 pole motor provides a means to obtain extra torque and produces a cooler running motor with these heavy cars.
Most 10th scale motors are 2 pole with kv's starting at 2000 for a 17.5 turn all the way up to 10,000 for low turn mod motors. Being limited to 7.4 volts and a fixed motor design, more power can only be produced by gearing down and upping the rpm's on the motor. Also, simply being able to gear a motor correctly makes the 4 pole motors a better choice as most 2 pole motors can't be geared low enough in current 8th scale drivetrains to make up for their very high kv.
10-05-2010, 09:58 PM
#9636
Ok thanks. I was just curious, if there was more to it than just a choice.
10-06-2010, 05:40 AM
#9637
hate to repost but.....Need a lil gearing and timing help. I am gear 17/46 on an rc8. Rx8 and 1400 with 6s. anyone else running this set up and whay do you have timing set at. Thanks guys. Oh and buggy weighs 7lb 13oz
10-06-2010, 07:31 AM
#9638
You probably won't need much timing on 6S, but you are probably 2-3 teeth undergeared. Go up to a 19 or 20.
10-06-2010, 07:55 AM
#9639
4 pole motors make more torque at the expense of rpm.
Power is the result of torque multiplied by the rpm. These buggies need a lot of power to drive them, so you can either increase the rpm or the torque to produce more power (and then gear accordingly). In 8th scale we can run higher voltages at will to up the rpm, but it comes down to the motor's design as to its torque output. Going to a 4 pole motor provides a means to obtain extra torque and produces a cooler running motor with these heavy cars.
Power is the result of torque multiplied by the rpm. These buggies need a lot of power to drive them, so you can either increase the rpm or the torque to produce more power (and then gear accordingly). In 8th scale we can run higher voltages at will to up the rpm, but it comes down to the motor's design as to its torque output. Going to a 4 pole motor provides a means to obtain extra torque and produces a cooler running motor with these heavy cars.
10-06-2010, 08:43 AM
#9640
Randy/Ty,
Curious what the BEC in the RX8 can handle for amperage draw?
Reason I ask is I got to thinking about my recent RX8 failure and it happened after I dropped my 7950 in there. I've seen as high as 4-amp spikes at stall so wondering if that load could have contributed to it's demise.
I've since added a cap to my Spectrum rx but haven't had a chance to really run it. Big pro-series race this weekend so trying to make sure I cover the details....
Curious what the BEC in the RX8 can handle for amperage draw?
Reason I ask is I got to thinking about my recent RX8 failure and it happened after I dropped my 7950 in there. I've seen as high as 4-amp spikes at stall so wondering if that load could have contributed to it's demise.
I've since added a cap to my Spectrum rx but haven't had a chance to really run it. Big pro-series race this weekend so trying to make sure I cover the details....
10-06-2010, 08:57 AM
#9641
The bec on the Rx8 is rated at 6v 5amps. Servos can often go over 8-10 amps but the spikes are usually handled. If you're experiencing brown outs or radio hits use a receiver cap.
The only servo that I've seen cause a major issue was the JR Hv servo. That thing is a monster drawing more current than any 1/8 servo really should...
Make sure your epas are set correctly. This single step alone can not only save a servo but prevent brown outs with the DSM systems.
The only servo that I've seen cause a major issue was the JR Hv servo. That thing is a monster drawing more current than any 1/8 servo really should...
Make sure your epas are set correctly. This single step alone can not only save a servo but prevent brown outs with the DSM systems.
10-06-2010, 09:14 AM
#9642
Ya, I've already got a CAP installed but just got me thinking.
Like I said, I haven't run it since i got it back together but this weekend is a big race. I've gone through the entire setup including re-setting EPA (setting mugen for max steering at ride height vs full droop) so there is some increased load at full lock/full droop but generally your under braking so the system is closer to ride height. Overall, it's worth about 12+pts on epa.
We'll see how it works out.
Like I said, I haven't run it since i got it back together but this weekend is a big race. I've gone through the entire setup including re-setting EPA (setting mugen for max steering at ride height vs full droop) so there is some increased load at full lock/full droop but generally your under braking so the system is closer to ride height. Overall, it's worth about 12+pts on epa.
We'll see how it works out.
10-06-2010, 09:45 AM
#9643
Any chance that the next RX8 software upgrade could allow us to adjust the bec to push more voltage to the servo? I really miss the power/speed/torque that my 7955 had on unregulared lipo when my truggy was still a nitro. Im not really happy with adding an external bec, is why i ask.
10-06-2010, 09:52 AM
#9644
The BEC on the Rx8 is not adjustable.
If you need that feel back you can also run a rx pack instead of the BEC.
If you need that feel back you can also run a rx pack instead of the BEC.
10-06-2010, 03:46 PM
#9645
Ok so if you plug in a rx pack, the servo automatically takes the power from it?