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Beginner on road electric questions...

Beginner on road electric questions...

Old 03-24-2011, 12:05 PM
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Default Beginner on road electric questions...

1. What is a ramped motor?

2. Is there a guide to convert brushless kvs to turns?
Or is that not how it works.

3. What is a good operating temp range on motors after a run?

4. Is it worth the extra money to get a 65c 2s lipo over a 45 c?

Thanks
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Old 03-24-2011, 12:42 PM
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Originally Posted by moto0013
1. What is a ramped motor?

2. Is there a guide to convert brushless kvs to turns?
Or is that not how it works.

3. What is a good operating temp range on motors after a run?

4. Is it worth the extra money to get a 65c 2s lipo over a 45 c?

Thanks
1 - i have never heard of one.

2 - two very different things, one doesnt have anything to do with the other

3 - depends brushless or brushed but NO heat is ideal, but typically a brushless motor is between 120-140F. over 200F and the motor will be destroyed.

4 - 45C is plenty for a battery.
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Old 03-24-2011, 01:32 PM
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1) They are not referring to the motor, but to an ESC/speed control that has dynamic timing advance. The timing ramps up as the motor speed increases. The ideal amount of timing advance changes as RPM changes to get best performance and keep temps reasonable. Mostly used in stock & spec race classes to get a lot more performance out of stock & spec (rules limited) motors.

2) Not a direct relationship, but this chart from Novak can be used for a rough guide:

http://teamnovak.com/products/brushl...spec_chart.htm

Generally sensored BL motors are rated by turns, sensorless by kv. They frequently have different powerbands and sometimes don't correlate all that well.

3) I agree 120-140F is a good reasonably safe quite usable range. Anything over 160-170F is starting to get iffy, depends some on the motor brand & construction though.

4) Agree, while more C is good, not much improvement after 40~50C for most uses.
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Old 03-24-2011, 01:40 PM
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Default One more thing

The temperature of the motor can safely go above 170 if you have a thicker rotor. Several manufacturers allow you to replace the rotor with thicker ones which gives you more magnetic material and more torque. Some can safely be run up to 200.
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Old 03-24-2011, 01:49 PM
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the heat in motors is a problem for motor manufacturers that use glue to fix their magnets inside the can. the glue melts at about 200F. some motors have thier magnets attached with glue and bolts which will allow temps above 200F. but those temps will decrease the life of the motor since the resin on the windings will also liquify at those temps.

i didnt know that about sensorless (turns) and sensored (kv), thanks!
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Old 03-24-2011, 02:23 PM
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Also have to take the impact on the magnets into account. High temps can reduce the magnetism of the rotor. Which then tends to make the motor run hotter, can be a vicious cycle.

Most welcome, always try to help a little where I think I can.
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Old 03-24-2011, 02:47 PM
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Thanks for the info guys. Is there somewhere to get info on timing of motors. How do I tell if I can do that?
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