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Old 10-22-2007, 08:40 PM   #181
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Default what is too hot?

1) What temp does a Novak 13.5 theremal?
2) Is it possible to get a sintered rotor 13.5 that hot?
3) Is there a "target" temperature for a 13.5 sintered rotor?

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Old 10-22-2007, 09:02 PM   #182
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1) What temp does a Novak 13.5 theremal?
2) Is it possible to get a sintered rotor 13.5 that hot?
3) Is there a "target" temperature for a 13.5 sintered rotor?

Hey Bob, I -think- the Novak GTB is what handles the cutoff of the motor, and I believe it's 180 degrees. I don't think the LRP ESC will do thermal shutdown for motor temp, but it will shutdown if the ESC is too hot. I also don't know if the LRP or Feigao motors have an internal temp sensor like the Novak motors do.

As for the other questions, I'm not sure. My motors are always clearly overgeared before they get hot enough to shut down, so I haven't pushed it hard enough to see. External factors could cause it though, like a bound drive train. John Stranahan had trouble with the front bearing going out in his 3.5 motors, and they'd overheat and burn. Apparently the "locked rotor detection" in the ESC wasn't fast enough to prevent it from taking the ESC and LiPo battery with it.
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Old 10-22-2007, 09:49 PM   #183
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Originally Posted by Fastforward View Post
1) What temp does a Novak 13.5 theremal?
2) Is it possible to get a sintered rotor 13.5 that hot?
3) Is there a "target" temperature for a 13.5 sintered rotor?

1. 175*F But only with a Novak ESC, LRP has no motor temp shut down
2. Sure but it dosent hurt Sintered Rotors. 175*F is where bonded rotors start to get hurt.
3. No, just gear for the fastest lap time. Forget about motor temp with sintered rotors...its all about lap times. Gear ups until they stop improving and then drop back one tooth.

Note that guys with good setups that drive well and maintain fast corner speeds can run bigger gears than less experience racers. Gear for what makes YOU fastest. Do not gear based on the local fast guy.
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Old 10-22-2007, 10:16 PM   #184
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Note that guys with good setups that drive well and maintain fast corner speeds can run bigger gears than less experience racers. Gear for what makes YOU fastest. Do not gear based on the local fast guy.
That's an extremely good point that often goes unspoken, or unnoticed. I hope others read this and keep it in mind.
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Old 10-22-2007, 11:07 PM   #185
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1. 175*F But only with a Novak ESC, LRP has no motor temp shut down
2. Sure but it dosent hurt Sintered Rotors. 175*F is where bonded rotors start to get hurt.
3. No, just gear for the fastest lap time. Forget about motor temp with sintered rotors.
Not true

The Sintered rotor will break down at 130*C eg 240*F
I have overgeared and lost one rotor that does not have any punch left anymore due to overheating.This was on a GTB with a SS13.5 new design. I got a new rotor and the motor was like new.
Try not to overgear and check Motor temp...I keep my motors in the 130*F range, and they are fastest at that temp for my track.

BTW Sintered is a Bonding process for metal powders: plane and simple.
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Last edited by Skruger; 10-23-2007 at 10:54 PM. Reason: I am a idiot
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Old 10-22-2007, 11:10 PM   #186
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Originally Posted by AdrianM View Post
its all about lap times. Gear ups until they stop improving and then drop back one tooth.

Note that guys with good setups that drive well and maintain fast corner speeds can run bigger gears than less experience racers. Gear for what makes YOU fastest. Do not gear based on the local fast guy.
Strongly agree
But still check temp...
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Old 10-22-2007, 11:14 PM   #187
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175*F is where bonded rotors start to get hurt.
But you can ZAP a Bonded Iron rotor back to Life .Not the Neo sintered.
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Old 10-23-2007, 10:29 AM   #188
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I have had my Novak Pro 10.5 (Sintered) and LRP X11 4.5 up to 190*F and they are still turning the same lap times as when they were new. Sintered rotors by their nature are desigend to run to just over 200*F before they start to weaken and they should return to full strength after cooling off.

Bonded rotors weaken at ~180*F and then they are toast...or so I thought. I didn't know you could zap them.
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Old 10-23-2007, 10:35 AM   #189
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Not true

The Sintered rotor will break down at 130*C
I have overgeared and lost one rotor that does not have any punch left anymore due to overheating.This was on a GTB with a SS13.5 new design. I got a new rotor and the morot was like new.
Try not to overgear and check Motor temp...I keep my motors in the 130*F range and that are fastest at that temp for my track.

BTW Sintered is a Bonding process for metal powders: plane and simple.
i think you have a typo? because there's a huge difference in 130 degrees CELSIUS...and 130 degrees Fahrenheit.
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Old 10-23-2007, 01:23 PM   #190
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i think you have a typo? because there's a huge difference in 130 degrees CELSIUS...and 130 degrees Fahrenheit.
I was thinking the same thing....but if he's thermaling at 130F then I'd say check your temp gun because 130 isn't going to thermal.
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Old 10-23-2007, 01:29 PM   #191
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Thanks to everyone who responded to my questions on tempertuare and rollout. I followed your advice and geared up 7 (yes seven) pinion teeth from where I had been and picked up about a half a second a lap. The temp at the motor went from 130F to 150F, but from what you guys are telling me that is not a concern for 13.5 sintered rotor.

Thanks for the help.

Big Bad Bob
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Old 10-23-2007, 01:42 PM   #192
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Can anybody confirm that there's a correlation between a motor's air gap, and its torque? Or, how much it "cogs" and its torque. I'm under the impression that the Orion with its large air gap and low cogging would be more of an RPM motor and require less gear than the Novak and LRP, but I've heard people say it actually has more torque.
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Old 10-23-2007, 02:13 PM   #193
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Originally Posted by syndr0me View Post
Can anybody confirm that there's a correlation between a motor's air gap, and its torque? Or, how much it "cogs" and its torque. I'm under the impression that the Orion with its large air gap and low cogging would be more of an RPM motor and require less gear than the Novak and LRP, but I've heard people say it actually has more torque.
I know there is defiantly a correlation between air gap and torque. Back in the good old days when I was racing slot cars as a kid we use to shim the magnets out toward the armature by putting masking tape on the back of the magnet. The result is more torque and to some extent less top RPM. I am sure there is some formula for calculating the ideal air gap but it is probably based on efficiency, not performance. Naturally if you are trading performance for efficiency, you are going to generate more heat as a by product.

Because braking is just the reverse action of making power, it would follow that if the air gap decreases braking effect would increase.

You can Google search "eclectic motor air gap calculation" and find lots of interesting stuff. Here is a link to an article titled "The necessary evil, air gap in rotating machinery"

http://findarticles.com/p/articles/m...n15349943/pg_1

BBB

Last edited by Fastforward; 10-23-2007 at 02:37 PM. Reason: added link
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Old 10-23-2007, 05:54 PM   #194
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Originally Posted by syndr0me View Post
Can anybody confirm that there's a correlation between a motor's air gap, and its torque? Or, how much it "cogs" and its torque. I'm under the impression that the Orion with its large air gap and low cogging would be more of an RPM motor and require less gear than the Novak and LRP, but I've heard people say it actually has more torque.
You are correct smaller rotors cog less. They have less torque but turn more RPM all other things being equal(wind, wire gauge, stator material, etc...).

Expect to see some optioins in this respect from Novak and LRP soon
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Old 10-23-2007, 10:37 PM   #195
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Cool I got to go back to www.EarnMyDegree.com

My bad
I should not have used CELSIUS and Fahrenheit in the same responce
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