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Old 06-24-2014, 08:33 AM   #46
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Originally Posted by howardcano View Post
I believe you meant 90A.

Your calculation is for input power. Output power is much less (by at least 50%).

But this does illustrate why they get so hot! A 540 motor can't dissipate 360W for very long before it melts down, so we gear for temperature. (Almost all of the normal motor/battery combos we run are similarly thermally-limited.) Not to mention that the batteries wouldn't last for the length of the race. And then of course there's the mitigating factor of not using full throttle for a large portion of a lap on a typical road course.

We were talking about the tabs, and although they don't look much different on the D4 versus other motors, oversized tabs could be a useful way to dissipate some heat. Maybe we'll see that in the future.
Yes I did mean 90 amps!

No disrespect intended, I am just trying to learn. So when the manufactures advertise their 17.5 at 22-28 amps (seems to be pretty common numbers listed for 17.5) that is average amp draw? If they draw 50-60 amps at 8 volts wouldn't that mean 400-480 watts? Or does the actual wattage change due to efficiency & heat?
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Old 06-24-2014, 08:41 AM   #47
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They are waiting for the dealer spacifics of the roar part to be handled. First shipment should handle this and it will be on roar list by the end of next month.
I am willing to bet this motor will take the longest to get on the list, if at all, in the history of ROAR...

ROAR hates Trinity.... lol.

FREE the 3.5!!
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Old 06-24-2014, 08:58 AM   #48
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I am willing to bet this motor will take the longest to get on the list, if at all, in the history of ROAR...

ROAR hates Trinity.... lol.

FREE the 3.5!!
Really? How much do you want to bet? I seriously doubt you will win
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Old 06-24-2014, 10:46 AM   #49
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Originally Posted by d16dcoe45 View Post
Yes I did mean 90 amps!

No disrespect intended, I am just trying to learn. So when the manufactures advertise their 17.5 at 22-28 amps (seems to be pretty common numbers listed for 17.5) that is average amp draw? If they draw 50-60 amps at 8 volts wouldn't that mean 400-480 watts? Or does the actual wattage change due to efficiency & heat?
I did not sense any disrespect, and I certainly do not intend any myself, despite my sometimes terse comments. I learn much from everybody here on RCTech. For instance, I gave current drain at 8V ("terminal voltage", if one can use that term for a brushless motor), while Dale gave current drain when using a LiPo and speed control, both of which can have significant losses that reduce the available voltage to the motor. Both are good data points, depending on what information one desires.

Unless a manufacturer states actual test conditions and methods of measurement, then any numbers they provide have limited value, and we are left to guess what they mean. 22A to 28A could be a typical average (perhaps on the high side) for what one might encounter during a 6 minute run while maintaining the motor within its operating temperature limit. But that's only a guess on my part.

The output power changes with almost everything! But we must always pump in more power than the useful power we get out to move the car. The rest comes out as heat (and a very little bit as sound, if we are getting picky). That's why the curves for both output power and efficiency are important. Yes, 50A or 60A at 8V (at the maximum power output point) would be 400W or 480W input, but less than half comes out as useful power.
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Old 06-24-2014, 08:10 PM   #50
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As far as I know - The D4 has already passed inspection and this initial shipment/sales will cover the "availability" part of the approval process. Meaning that the motor should be on the ROAR approved list in time for the Paved Nationals coming up next month.

Yes, it is a typo and should say rotors instead of stators.

I've seen the motor in person and it is quite a bit lighter than a D3.5. The other big thing I noticed right away was how much shorter the D4 is than the D3.5. The sample I saw at the Pre-WC was a bit too short for the 50mm minimum lenght.

I was shocked to see the machining that they put into this one. It's a really nice piece and knowing a bit of what went into it, I can say it's not a copy of any other company out there. Jim did a great job with this one and I'm sure it will replace the D3.5 as the motor of choice for this year.
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Old 06-25-2014, 02:29 AM   #51
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If you'd like to discuss in a more suitable thread, let me know; I'm very interested. I'm sure you have plenty of practical experience to share!
That sounds like a good idea to save hijacking this thread! Lets use the old Sentry Dyno thread since that's what mine is based on:

Dyno, Homemade, Using a Novak Sentry Data Logger, Continued, The Experimental Thread.
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Old 06-25-2014, 04:13 AM   #52
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Originally Posted by Josh Cyrul View Post
As far as I know - The D4 has already passed inspection and this initial shipment/sales will cover the "availability" part of the approval process. Meaning that the motor should be on the ROAR approved list in time for the Paved Nationals coming up next month.

Yes, it is a typo and should say rotors instead of stators.

I've seen the motor in person and it is quite a bit lighter than a D3.5. The other big thing I noticed right away was how much shorter the D4 is than the D3.5. The sample I saw at the Pre-WC was a bit too short for the 50mm minimum lenght.

I was shocked to see the machining that they put into this one. It's a really nice piece and knowing a bit of what went into it, I can say it's not a copy of any other company out there. Jim did a great job with this one and I'm sure it will replace the D3.5 as the motor of choice for this year.
Josh, All I have seen so far is the 17.5. I assume they will offer the D4 in the other winds as well?
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Old 06-25-2014, 11:26 AM   #53
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Josh, All I have seen so far is the 17.5. I assume they will offer the D4 in the other winds as well?
17.5, 13.5 and mod they are waiting for a ruling of what a 10.5 needs to be from ROAR before they waste money making one
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Old 06-25-2014, 07:15 PM   #54
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[QUOTE=tessty71;13360261]17.5, 13.5 and mod they are waiting for a ruling of what a 10.5 needs to be from ROAR before they waste money making one[/

Ok after reading your post again, I see what your talking about.

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Old 06-25-2014, 07:16 PM   #55
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Sucks to be the guy who bought the prototype for $500.
Not really, he also got a brand new production motor too!
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Old 06-26-2014, 12:59 PM   #56
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Got a 17.5 on the way. Anyone who has run one or has any inside info have any suggestions for gearing? Should I gear/time it like a KS with rpm stator & torque rotor? I was thinking 55 deg & 3.7 in sedan med/large asphalt track. Am I off base?
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Old 06-26-2014, 07:42 PM   #57
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Just got the D4 17.5's in today and 13.5's will be here tomorrow. They look pretty good in hand but havent torn one apart yet. You can tell its lighter just by holding it and it looks shorter too but I havent measured it yet.

They are up on the site if anyone is looking for one.

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Old 06-26-2014, 07:54 PM   #58
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It's interesting to see the motor is slightly shorter... Maybe, just maybe, Trinity is following the motor trends over here in Japan...
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Old 06-27-2014, 06:28 AM   #59
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Any idea what rotor they are coming with? 12.5 turquoise torque? 12.5 pink rpm? Broadband?
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Old 06-27-2014, 06:31 AM   #60
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First batches have the 12.3mm Broadband Purple rotor.
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