Question on motor and speed control temp..

[axthomson]

i have a scorpion HK-3026-1210 and a scorpion 90 amp esc w/ sbec and wireless ESC programer. I just finished setting it up today and afterits first flight, about 10-11 mins. we landed and the motor was hot, but not to where you couldnt touch it, but the heat shrink on the ESC had partialy melted and was to hot to touch.

I have the stock 42t and 61t gears w/ 15 tooth pinion. futaba 9254 servo w/ gy401, an JR servos that came with the DX7. the aircraft flys great and has lots of power. i re soldered everything, again tonight. and am going to try again tomorrow. but im wondering if anyone may have some other thoughts as to why it is doing this..

-thanx

[axthomson]

also my batteries are kong power 3s 3200. they get warm but barely.

[odieser]

Scorpion Commander 90A ESC
Max Continuous Current ..................................... 90 Amps
Operating Voltage Range ............................... 6 to 15 Volts
this is from innov8tive design website
may be the problem as Two 3s batteries is 22.2V which is too much for the ESC
Mark

[axthomson]

thiis a new model speed controler, its good for 26 volts.

[odieser]

okay sorry no new info on their site

[axthomson]

im gonna try an external BEC, this one has a 5a switching BEC @5v built in, but im going to use an external and see what happens.

[HighNear90]

Did the external BEC help?

[ps61785]

iv got the same motor and the CC80 ESC and run flight power 3700mAh evo25's and i have no heat problems...

Running a 13t pinion with stock gears and a 20t auto rotation gear.

Ran for 9-10 minutes last not at a solid 90% throttle curve hovering around and doing some collective pops every now and then. Temp gunned the motor after the flgith and it was 77 degrees. The batteries were around 80 and the ESC was 88 degrees. It was only 20 degrees out last night but still seems very reasonable for a 10 minute flight.

I wish that i could find the equation to find the head speed given the gears that i am using...

Anyone know that equation...

[istandalone]

man, i wish my motor ran that cool! i've got the rcp 1000w 1100kv and after a pair of packs it's around 105f. the esc and packs stay pretty cool though.

[Happy|Harry]

I wish that i could find the equation to find the head speed given the gears that i am using...

Anyone know that equation...


i've attached an H550 headspeed calculator :)

[skydude]

, but the heat shrink on the ESC had partialy melted and was to hot to touch.

-thanx

That seems extremely hot. I have had hot esc's (too hot to touch) and never melted plastic.

My latest build (hurri 550) started out heating the motor and esc. Guys here steered me to a higher motor rpm and it worked like a charm.

--

[ps61785]

that could be as i am running a 1210kV motor and had not heat issues at all...

Does anyone have the actual equation to find headspeed....the program is great but i prefer to know how to get to those numbers...

[MTDV]

- Efficiency (Eff): a percentage that use to calculate the actual running of the motor
For example: 90%
- Voltage (Vnorm): a norminal voltage of your battery
For eaxmple: 22.2V for a 6S pack (a signle cell polymer battery can hold up to 4.2V right after the charge, but the norminal voltage is 3.7V)
- Motor KV (KV): a number that is defined by manufacture to give an approximate number of round per minute (RPM) per Volt.
For example: 1100KV means at every Volt the motor will produce 1100 RPM
- Gear Ratio (Gratio): a ratio of your main gear to the motor pinion.
For example: 10 (main gear 100T, and pinion 10T, so the gear ratio is 100T/10T = 10)

Having all of these numbers you can calculate the head speed a follow:

1. Calculate the real Voltage that is used to produce RPM:
Vreal = Vnorm * Eff
Example: Vreal = 22.2V * (90/100) = 19.98V
2. Calculate the actual RPM that produces by your batter pack:
RPMreal = Vreal * KV
Example: RPMreal = 19.98V * 1100(RPM/V) = 21978 RPM
3. Calculate Head Speed (HS):
HS = RPMreal / Gratio
Example: HS = 21978 / 10 = 2197.8 RPM
Hence, the head speed in this example is 2197.8 RPM

Hope this little hint would help you to calculate your heli head speed.

[ps61785]

yeah i actually knew all of that...its the two stage gear train that i am having trouble with...any ideas on how to figure the ratio from motor to head out...

[MTDV]

Oh that is simple. Just take the gear ratio of each stage and multiply them together. Math can be setup like this

First stage gear ratio:
Main gear 1 Pinion 1
45T 15T
--> So 1 revolution of main gear 1 allows (45/15) revolutions of pinion 1

Second stage gear ratio:
Main gear 2 Pinion 2
50T 12T
--> So 1 revolution of main gear 2 allows (50/12) revolutions of pinion 2

However, main gear 2 and pinion 1 are tied together, so from the first stage (45/15) revolutions of main gear 2 would allow you to have (45/15)*(50/12) revolutions of pinion 2. Or state the other way, one revolution of main gear 1 allow (45/15)*(50/12) revolutions of pinion 2.

I hope this helps and prove the math, and this can be used for n stages of gear ratio.

Happy landing

Minhtuan

[istandalone]

what i'd like to know is, how hot is too hot for the motor? should i worry when i temp mine at 105-115f?

[mjdee14]

what i'd like to know is, how hot is too hot for the motor? should i worry when i temp mine at 105-115f?

They say if you can touch it for 10 secs or so...it is OK....I would not think 105 f is too hot....but maybe someone elsewill chime in...that is more of a motor expert.....

On a normal 80 deg day that only 25 deg higher...and only a few deg higher than body temp.