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Brushless Motor FAQ

Brushless Motor FAQ

Old 08-06-2006, 03:31 PM
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Default Brushless Motor FAQ

Q: Tell me about Novak's brushless motors, and how they compare to brushed motors.

A: 3.5R - Comparable to a 6T brushed motor. This is the fastest sensored brushless motor commonly used in R/C. It ships with the new "sintered" rotor which currently makes it illegal under ROAR rules for modified racing.

4.5R - Similar to a 7T brushed motor. Legal for modified racing under ROAR rules.

5.5R - Similar to a 10T brushed motor. Legal for modified racing under ROAR rules.

6.5R - Similar to a 11-12T brushed motor. Legal for modified racing under ROAR rules.

7.5R - Similar to a 13-14 brushed motor. Legal for modified racing under ROAR rules.

SS5800 (8.5R) - Similar to a 19T in performance, if not slightly faster, and with more acceleration. Currently ships with the old styled rotor and endbell which can be updated with Novak's upgrade kit. The upgrade kit generally gives the motor more torque and slightly less top speed.

9.5R - Rumored, not yet available. This motor is expected to perform very similarly to a 19T brushed motor.

SS4300 (10.5R) - Between a 27T stock and 19T in performance, with significantly more torque than a stock motor, and slightly better top speed. Currently ships with the old styled rotor and endbell which can be updated with Novak's upgrade kit. The upgrade kit generally gives the motor more torque and slightly less top speed.

SS13.5 - Designed to perform just like a 27T stock motor. Initial testing indicates that it's extremely competitive with today's hot stock motors.

Crawler 18.5 - Slower brushless motor designed with low-speed applications (such as crawling) in mind.

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Q: What about Reedy's brushless motors? Are they different than Novak's? Can they work with Novak's GTB ESC?

A: 5-Star (4.5 turns?) [rumored, not yet available]
4-Star (5.5 turns) - Similar to a brushed 10T motor.
3-Star (6.5 turns) - Similar to a brushed 11-12T motor.
2-Star (7.5 turns) - Similar to a brushed 13-15T motor.
1-Star (8.5 turns) - Similar to a brushed 17-19T motor.

Reedy's motors are very similar to Novak's, and will work with the Novak GTB speed control. Novak's motors will in turn also work with the LRP Sphere speed control. Novak seems to have superior rotor technology available at this time which may give their motors more performance and resistance to heat when using sintered rotors. Many of the Novak motors also have an improved soldering tab system not yet seen in the Reedy motors. The sensor wire harness on Reedy motors is removable, making it easy to replace if damaged. Novak motors use the same style harness, but it's permanently attached to the motor and will require factory service to repair.

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Q: What does "sintered" mean? How is it relevant to motors?

A: Current BL motors use a bonded rotor, magnetic particles in a thermoset resin cast into shape. The limiting factors with bonded rotors are temperature and RPM. They become damaged and lose power if run at high temperatures (over 190 deg F) for extended periods. At high RPM centrifugal forces and thier resulting shaft harmonics can make the rotors fragment.

Sintered rotors are magnetic particles mixed with a metallic ceramic powder and fused (sintered) together under tremendous temperatures. These magnets are safe to run up to over 250 deg F and they are way stronger. As a results we can gear higher and run at higher rpm with much less risk of damaging a rotor. (-AdrianM)

Only the Novak 3.5R ships with a sintered rotor. For all other Novak BL motors, the sintered rotor is available as an upgrade. Sintered magnets are currently not legal under ROAR rules, and will render your motor illegal for sanctioned competitions.

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Q: Can I shorten the wires of the sensor harness?

A: No. Well, maybe, but you shouldn't. These aren't standard wires, and are extremely difficult to work with and solder. Novak has stated that many of their repairs on brushless motors come from people who have tried to alter the sensor wires.
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Old 08-06-2006, 03:31 PM
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There's a lot of threads about brushless motors with a lot of good information spread across all of them. I'd like to start a collaborative FAQ about brushless motors (that means you guys get to help) and I'll keep the very first post updated with information as we all work together to flesh out details. Please contribute anything you feel is relevant and factual, and I'll handle the duties of keeping things updated.
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Old 08-06-2006, 04:07 PM
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On Novak, the 4.5 is not like a 7 turn. It is a 4.5 turn, period. On LRP, the 4 star is like a 7 turn and the 3 star like a 9t.
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Old 08-06-2006, 04:18 PM
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Originally Posted by bxpitbull
On Novak, the 4.5 is not like a 7 turn. It is a 4.5 turn, period. On LRP, the 4 star is like a 7 turn and the 3 star like a 9t.
I'm confused? The idea was just to give as rough idea of brushed equivilant motors. Are you saying the 4.5 isn't comparable to a 7-8T brushed in performance?
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Old 08-06-2006, 04:32 PM
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Thats exactly what I am saying. The 4.5 is faster than a brushed 7 turn. Novak designed it not to be equivalent. The Novak Super sport series motors are the equivalents 4300 and 5800. The 5800 is equivalent to a 8.5 and the 4300 is a 10.5. The 4.5, 5.5, 6.5 and 7.5 are exactly what they are numbered. I ran a 7x2 D5 in my Pro 4 and then when I upgraded to the 4.5, it was the difference between a fast running barn horse and a thoroughbred race horse. Call Novak, they will tell you just that. The brushless motors that cant be powered by their supersports are no way near equivalent, but SUPERIOR.
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Old 08-06-2006, 04:43 PM
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syndr0me,
Good work with a start to a nice brushless FAQ! I suggest adding some more to it. Start with the very basics concerning the different technology and the advantages it offers. Teach it as if you are talking to newbies. Thousands of people read these forums without replying.
You could even include a diagram like this one too:
http://www.servomag.com/flash/2-pole...ldc-motor.html

Also be sure to include a Q and A concerning the LRP speed controller's ability to use Novak brushless motors.

A picture or 2 of some brushless motors also helps. You may also want to include how they are hooked up differently than brushed. For those who want a fast way to switch back and forth from brushed to brushless, read this post I wrote.

I know it's repetitive to type, but in your FAQ, everywhere you type something like "27T stock", don't assume the reader knows that you are referring to brushed. Spell it out in every instance in your FAQ if you are referring to brushed or brushless turns.

Last edited by James35; 08-06-2006 at 04:55 PM.
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Old 08-06-2006, 04:50 PM
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Originally Posted by bxpitbull
Thats exactly what I am saying. The 4.5 is faster than a brushed 7 turn. Novak designed it not to be equivalent. The Novak Super sport series motors are the equivalents 4300 and 5800. The 5800 is equivalent to a 8.5 and the 4300 is a 10.5. The 4.5, 5.5, 6.5 and 7.5 are exactly what they are numbered. I ran a 7x2 D5 in my Pro 4 and then when I upgraded to the 4.5, it was the difference between a fast running barn horse and a thoroughbred race horse. Call Novak, they will tell you just that. The brushless motors that cant be powered by their supersports are no way near equivalent, but SUPERIOR.
I think you might be confused. The numbers like 4.5, 5.5, etc are the actual number of turns inside the can of the brushless motor, and not an actual representation of its brushed motor equivalency. Even though both brushed and brushless motors are rated by turns, the numbers do not compare directly between the two types of motors. This is a common misconception, and one of the harder concepts for people to grasp when dealing with brushless.
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Old 08-06-2006, 05:08 PM
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syndr0me you are exactly right on the numbering scheme. and bxpitbull, the 4.5 is a liitle slower than my shock 8 x 1. the numbering of the brushless motor does indicate the number of winds epoxied to the inside of the motor can.
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Old 08-06-2006, 05:12 PM
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Thanks for the comments so far guys. My current list isn't intended to be the definitive FAQ. I'm hoping others will collaborate and contribute to it, and I'll keep the very first post updated with current information so we can direct people here when they start asking questions.
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Old 08-06-2006, 06:04 PM
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Today how fast a BL motor is totally depends on speedo and motor temperature. Temperatures are affected by ambient air and track surface temps, gearing and vehicle weight.

An 8.5 BL motor (Novak 5800 or LRP/Reedy/Nosram 1 Star) in a sedan on a hot day is as fast as a good 19 BR motor. The high air/track temp and the weight of the car require you to limit the gear ratio to prevent overheating.

An 8.5 BL in a light 4 cell oval pan car, indoors on a high speed track can be geared up to be as fast as a 7 turn. The light load and low ambient temps let you run more gear and get more speed out of the motor.

This is why diffrent guys report diffrent findings when comparing BL and BR motors.

The sintered rotors will make the BL motors more consistant across temp ranges. ROAR ands all the other sanctioning bodies are looking at sintered rotors for 2007.
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Old 08-06-2006, 10:34 PM
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I think the 5.5 would be more of a 9 to 8 turn motor.
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Old 08-07-2006, 01:51 AM
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Originally Posted by Z.Hallett
syndr0me you are exactly right on the numbering scheme. and bxpitbull, the 4.5 is a liitle slower than my shock 8 x 1. the numbering of the brushless motor does indicate the number of winds epoxied to the inside of the motor can.
I guarantee the individual you ran against had it geared incorrectly. My 4.5 is a rocket and there is no way on the planet someone with anything less than a 7x2 roundwire keeping up with me. An 8 single doesnt spool hard enuf to hang with a 7x2 and most certainly cannot hold a can of dog piss next to a 4.5. But, you are there and I am here, so I guess we will never kniow. Bu that being said, when people run open modified (pros) I see more 4.5's, 7 doubles and singles.....no where in the pack is a 8x1 mentioned.PLEASE man.
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Old 08-07-2006, 02:19 AM
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Hi bxpitbull

LRP 4-Star (5.5 turns) - Similar to a brushed 10T motor. <-- is it correct?
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Old 08-07-2006, 06:05 AM
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At least my LRP 4-star is way much faster than my 10T brushed...
On a very flowing track, top speed can be almost the same, but 4-star is noticable faster out of the corners. Keep in mind that i have not geared it on maximum
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Old 08-07-2006, 02:18 PM
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Last race meeting my 5.5 was hanging with 8th scale nitro cars, I don't think a 10 turn could do that.
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