Novak Ballistic goes Spec
02-22-2011, 04:27 PM
#331
Our epoxied, Ballistic 540, replacement wound stators are now in available in our store. Available winds are from 6.5T through 25.5T.
Novak's Ballistic Epoxy Dipped Hand Wound Stators – 6.5T - 25.5T feature the added benefits of epoxy. Each stator offers strengthened reliability and higher power operation performance of the motor— ideal for extreme racing conditions.
The Ballistic Hand Wound Stator is dipped in a special motor winding epoxy and then oven-cured for several hours. Once the epoxy is cured, it prevents the wires in the stator from moving or rubbing against the laminations and other wires in extreme conditions. Preventing this unwanted contact avoids shorts in the motor coils which can lead to premature failure. The epoxy also helps transfer heat from the wires to the lamination, helping motor operation at higher power levels.
All around, the epoxy coating improves the reliability of Novak’s already high-quality stators and provides extreme vibration resistance. It also prevents illegal rewinding of the stator.
The Ballistic Hand Wound Stator is dipped in a special motor winding epoxy and then oven-cured for several hours. Once the epoxy is cured, it prevents the wires in the stator from moving or rubbing against the laminations and other wires in extreme conditions. Preventing this unwanted contact avoids shorts in the motor coils which can lead to premature failure. The epoxy also helps transfer heat from the wires to the lamination, helping motor operation at higher power levels.
All around, the epoxy coating improves the reliability of Novak’s already high-quality stators and provides extreme vibration resistance. It also prevents illegal rewinding of the stator.
02-23-2011, 09:54 PM
#332
I can't seem to find the 1300+ rotors on the site. Is it just me?
02-23-2011, 10:25 PM
#334
Interesting..... I really don't need another motor. I'll give it some time. Thanks.
02-23-2011, 10:30 PM
#335
the part # is S5952 for the 12.3 1300+ stator.
also, +1 for novaktwo's quote about the epoxyed stators! these are definitely for the guys looking for that extra little bit!
I have had the privalige of testig these stators, they are worth the extra $.
Last edited by ed517; 02-23-2011 at 10:42 PM.
02-23-2011, 10:37 PM
#336
I won't be at Norcal for a week or two. But I do have a gauss gauge on the way to me.
02-26-2011, 11:09 AM
#337
Epoxied Stators---Technical Update
In normal operation the brushless motor stator coils are subjected to high mechanical forces due to torque reaction and vibration as the motor coils are driven by alternating current. This constant pulling and pushing of current through the coils causes the coils to move in sync with the drive frequency and this force increases as the motor load increases.
Novak 17.5 turn brushless motor has a Kt value of approximately 0.7 oz-in. So, if during acceleration, the motor draws 100 amps, which is quite typical, the motor produces about 66 oz-in of torque (95% efficient motor) and there is equal and opposite reaction force in the coils ( Newton’s third law of motion).
Imagine 5.5 lb-in of force pushing on the coils, this small amount of movement will (over time) cause some damage. In order to improve the motor's reliability, the windings are epoxy impregnated.
The epoxy provides a degree of mechanical strength to the windings, particularly in the unsupported end wind. Where the coils enter the slot of the stator they are also strengthened in order to resist the forces caused by the torque reaction.
This coating prevents vibration caused by the changing magnetic fields. It prevents wires rubbing against one another which will eventually wear the insulating coating, causing a short in the coil.
Epoxy also displaces air (which is a thermal barrier) from inside the coil and replaces it with resin. This improves the thermal conductivity of heat from the inside of the the windings to the lamination on the outside. Since the laminations are on the outside, they are able to conduct heat to the ambient air.
Thermal Conductivity in W/m degree C ( 1W/m C = 0.5779 Btu/(ft hr F))
Air 0.024
Standard Epoxy 0.188
Epoxy with additive 1.7
As you can see, plain epoxy is 7.8 times better in heat conductivity than air; epoxy with thermal additives is 73 times better. This coating also provides a degree of environmental protection against the ingress of moisture, and also improves the electrical insulation between the winding and the stator.
Novak 17.5 turn brushless motor has a Kt value of approximately 0.7 oz-in. So, if during acceleration, the motor draws 100 amps, which is quite typical, the motor produces about 66 oz-in of torque (95% efficient motor) and there is equal and opposite reaction force in the coils ( Newton’s third law of motion).
Imagine 5.5 lb-in of force pushing on the coils, this small amount of movement will (over time) cause some damage. In order to improve the motor's reliability, the windings are epoxy impregnated.
The epoxy provides a degree of mechanical strength to the windings, particularly in the unsupported end wind. Where the coils enter the slot of the stator they are also strengthened in order to resist the forces caused by the torque reaction.
This coating prevents vibration caused by the changing magnetic fields. It prevents wires rubbing against one another which will eventually wear the insulating coating, causing a short in the coil.
Epoxy also displaces air (which is a thermal barrier) from inside the coil and replaces it with resin. This improves the thermal conductivity of heat from the inside of the the windings to the lamination on the outside. Since the laminations are on the outside, they are able to conduct heat to the ambient air.
Thermal Conductivity in W/m degree C ( 1W/m C = 0.5779 Btu/(ft hr F))
Air 0.024
Standard Epoxy 0.188
Epoxy with additive 1.7
As you can see, plain epoxy is 7.8 times better in heat conductivity than air; epoxy with thermal additives is 73 times better. This coating also provides a degree of environmental protection against the ingress of moisture, and also improves the electrical insulation between the winding and the stator.
02-26-2011, 12:11 PM
#338
In regards to this new thermal epoxy stators, I was wondering how much this has added to the weight of the stator?
Cheers,
Shawn.
Cheers,
Shawn.
02-26-2011, 12:15 PM
#339
I'd like to know how much cooler the motors have ran in back to back testing.
02-26-2011, 07:02 PM
#340
I just got my brand new Ballistic 17.5 motor today and was wondering what the actual timing of the motor is from the factory. I thought it was supposed to be 30*, but mine is reading about 26* or so according to the sticker and the tick mark. Is it that the person who put the sticker on did a poor job and put it on wrong? It's not a big deal, but just checking if the timing of the motor from the factory varies. Thanks and I look forward to racing this thing.
02-27-2011, 07:44 AM
#341
I just got my brand new Ballistic 17.5 motor today and was wondering what the actual timing of the motor is from the factory. I thought it was supposed to be 30*, but mine is reading about 26* or so according to the sticker and the tick mark. Is it that the person who put the sticker on did a poor job and put it on wrong? It's not a big deal, but just checking if the timing of the motor from the factory varies. Thanks and I look forward to racing this thing.
03-05-2011, 11:22 AM
#343
Tech Notes: Ballistic Epoxied Replacement Wound Stators
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Last edited by NovakTwo; 03-05-2011 at 01:51 PM. Reason: Dplicate post
03-05-2011, 01:05 PM
#344
you already said that. I read it again anyways. So can you tell me how much of a temp difference you guys have noticed?
03-05-2011, 02:00 PM
#345
For example, we are not increasing our motor temp guidance numbers. The stator epoxy coating will not prevent your rotors from weakening from repeated over-heating. I re-read our store listing and I cannot find any claim (by us) that your motor will run cooler with this stator.