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-   -   LRP SPHERE COMP. ESC (80700) (https://www.rctech.net/forum/electric-road/107427-lrp-sphere-comp-esc-80700-a.html)

Miu Miu 03-26-2006 07:49 AM

LRP SPHERE COMP. ESC (80700)
 
How does the new lrp sphere (80700) compare to the GTB?

Does the sphere need a fan on top to cool it down like the GTB does?

Can the sphere handles novak BL motor 4.5/5.5?

jarkko 03-28-2006 06:02 AM

We have had a week now a Sphere Comp. with a LRP 4-star motor. We are very pleased with it. Our junior has been driving a 9-turn in practise and he still races in stock. He says the power of the 4-star is just right for him now (punch setting at 2 (linear) out of max 6 (called very agressive).

The highish temperature of the motor has been a little bit of a surprise to us. Here I am comparing to a friends GTB/novak 5.5 combination. Their motor seems to run much cooler than ours.

One reason for the higher temp on both ESC and motor (motor 65 degrees C and ESC heatsink 65 C) is surely that we have set quite much motor braking on the ESC. It's now on setting 4 out of 6. We have kept the setting high because our driver likes to have considerable motor braking effect.

With the heat fins installed the temp of the ESC itself is kept some 20 degrees C lower than the heatsink. No fan needed.

Power wise the 4-star and Noval 5.5 are about equal at our small indoor track.

darmawaa 03-30-2006 04:34 AM

F/R
 
What is the advantage of making brushless speedos forward/brake only (no reverse), like the Sphere comp.
Any LRP guys might want to answer, maybe Reto?

Marcel 03-30-2006 05:21 AM

I'm sure that most of the drivers that use the Sphere Comp don't need Reverse.....
It's a pure competition speedo. Wpould be like Reverse on a QC2 or VFS-1....

I'm racing mine know since a month and i'm very happy with it. I used it on differen carpet tracks, minimum powerprogram 3, maximum 5.
You should try with these different programms, the difference between them is much larger than compared to the programs on an QC2.

TRF415boy 03-30-2006 05:36 AM


Originally Posted by darmawaa
What is the advantage of making brushless speedos forward/brake only (no reverse), like the Sphere comp.
Any LRP guys might want to answer, maybe Reto?

Reverse is illegal in most rule books...

darmawaa 03-30-2006 06:26 AM

on resistance
 
Would brushless speedos with forward/brake only (no reverse) by design has lower on resistance value than one with reverse? Considered everything being equal (# of fets, etc)
Would Sphere comp running cooler than GTB , both with 5.5turns motor and no heatsink&fan?
Thanks

burito 03-30-2006 10:47 AM


Originally Posted by darmawaa
Would brushless speedos with forward/brake only (no reverse) by design has lower on resistance value than one with reverse? Considered everything being equal (# of fets, etc)

No, reverse is a side effect in any brushless speedo. It basically comes for free... we simply feel, apart from not being allowed for racing, that reverse is not needed for a competition type speedo. less settings to mess around with (there's more then enough already)...

NovakTwo 03-30-2006 11:53 AM

Choice is a wonderful thing....
 
Many brushless users do not race competitivly. So Novak feels that offering two reverse profiles in our GTB Brushless motor controller gives the user more options and flexibility.

Adjusting the profiles with reverse is no more difficult than adjusting the forward/brake profiles.

Bob Novak 03-30-2006 02:45 PM

I disagree with burito on having reverse in a competition brushless speed control. Have you ever been out practicing and you get stuck somewhere on the track and it seems like an hour before any body helps you out? Well if you had a GTB system in your car and you had the reverse mode enabled you could just back up and get your self out of trouble.
Bob Novak

Bob Novak 03-30-2006 02:53 PM

Miu Miu asked how the new Sphere Competition compares with the Novak GTB. If you look at published specs on the Rds-on the LRP Rds-on=0.0009 ohms and the Novak GTB Rds-on=0.0004 ohms. The lower this number is the lower the heat that is generated in the speed control.
Bob Novak

AdrianM 03-30-2006 03:33 PM


Originally Posted by Bob Novak
Miu Miu asked how the new Sphere Competition compares with the Novak GTB. If you look at published specs on the Rds-on the LRP Rds-on=0.0009 ohms and the Novak GTB Rds-on=0.0004 ohms. The lower this number is the lower the heat that is generated in the speed control.
Bob Novak

Please dont take this the wrong way as I am not taking side in this question but..If the GTB runs cooler why is it so sensitive to chassis location and fan condition? If the fan stops running your race will be over shortly.

The LRP uses no fan and dosen't seem to have thermal shutdown issues.

Bryan Thng 03-30-2006 05:47 PM

Likewise, please do not take this the wrong way, it is for constructive discussion. I have been running the GTB ESC with the fan on my Xray T2 eversince I got it and it definitely does not have any thermal issues irregardless of chassis location. Rather it is the Velociti 5.5R motor that is getting the thermal issues even when using the recommended FDR or higher.

On the other hand, I have used the Nosram Storm 3-Star motor (which I reckon is similar to LRP Vector) with the GTB and it is certainly able to withstand a much higher temperature. Unfortunately for 2 friends of mine at our club, the temperature apparently got too high and their 3-Star rotor magnet cracked during the last minute of 7mins heats. They broke 3 motors in between them.

Also for this 3-Star motor that I got, one of the three 1.5mm screws securing the endbell was bent out of shape within when I disassembled it for my first maintenance. I am not sure if this was due to the result of use, or a factory assembly problem. Anyway, the Velociti is certainly more robust in design, although heavier.

I would like to try the LRP Sphere Competition when budget allows, soon I hope. :)

Miu Miu 03-30-2006 06:45 PM


Originally Posted by Bob Novak
Miu Miu asked how the new Sphere Competition compares with the Novak GTB. If you look at published specs on the Rds-on the LRP Rds-on=0.0009 ohms and the Novak GTB Rds-on=0.0004 ohms. The lower this number is the lower the heat that is generated in the speed control.
Bob Novak

hello Bob. thanks for your info. i did look at those figure on their sites, but it seems that most of the comment / feedback from users are the Sphere runs "cooler" and does not seem to need a fan to operate well

Miu Miu 03-30-2006 06:55 PM


Originally Posted by Bryan Thng
Likewise, please do not take this the wrong way, it is for constructive discussion. I have been running the GTB ESC with the fan on my Xray T2 eversince I got it and it definitely does not have any thermal issues irregardless of chassis location. Rather it is the Velociti 5.5R motor that is getting the thermal issues even when using the recommended FDR or higher.

On the other hand, I have used the Nosram Storm 3-Star motor (which I reckon is similar to LRP Vector) with the GTB and it is certainly able to withstand a much higher temperature. Unfortunately for 2 friends of mine at our club, the temperature apparently got too high and their 3-Star rotor magnet cracked during the last minute of 7mins heats. They broke 3 motors in between them.

Also for this 3-Star motor that I got, one of the three 1.5mm screws securing the endbell was bent out of shape within when I disassembled it for my first maintenance. I am not sure if this was due to the result of use, or a factory assembly problem. Anyway, the Velociti is certainly more robust in design, although heavier.

I would like to try the LRP Sphere Competition when budget allows, soon I hope. :)


yes...more constructive discussion is better. But the one u were talking about is not a LRP ESC and is not even a comp. version. I know there are some bad reports about the older version, burnt or not enough power / fast as the 5.5

but are there anymore feedback from the SPHERE COMP. VERSION? TA

burito 03-31-2006 05:07 AM

Hi Bob. Sorry to say so but your comparison of resistance between your GTB and our Sphere Competition is not correct at all!

We specifiy it differently. We specify the combined FET series resistance of both high-side and low-side FETs, because always two groups of FETs must be turned-on when a phase is fired. Therefore this is the correct total FET (speedo) resistance. You only specify half of the total FET resistance.

If we would rate ours the same way as you do, it would be 0.00045ohm. Hardly any difference then…


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