bob12

Hi All

I have recently purchased the Nemesis ARF 1560 mm from Hobby king.
with it i purchased the recommended accessories:

[h=4]Turnigy dlux 70A SBEC Brushless Speed Controller w/Data Logging[/h]NTM Prop Drive 35-48 Series 900KV / 815W
[h=4]Turnigy nano-tech 4000mah 4S 45~90C Lipo Pack[/h]Turnigy 12x8 Prop
[h=4]HK15288A Analog BB/MG Servo 51g / 9kg / 0.20s[/h]
After setting her up i measured the motor current with the throttle set to 50 % ( the prop was connected and i held the plane tight).
I measured the current with an AC clamp on meter on one of the three wires going to the motor.
the current was 60 A. Am i measuring this incorrectly ? as i am scared that i will fry my ESC if i go too 100% throttle.
should i rather measure the DC current from the Battery ?

Secondly, i am running 5 servos off the BEC of the ESC listed above . is a 3 A BEC sufficient ?

Any help would be greatly appreciated as i would like some clarity before i take her up.

many thanks
Bob

bob12

Hi All

i was using a "no name brand" clamp on meter. hence i queried the measurements.
I compared it to a Fluke clamp on and got the following results at 100 % Throttle:

motor phase current = 28 A
DC current from battery = 58 A

these results seem much more realistic.

i also measured the BEC current with all servos moving, and it amounted to a max of 1.5 A
and the voltage stayed at 5.6 V.

all seems fine. Problem solved.
many thanks
Bob

jester_s1

Yes, it does sound like you are ok. The current will go down a bit in actual flight since you won't be holding the plane back from moving then. The on ground test gives you the worst case scenario for amp draw.

opjose

BTW: You may want to measure the BEC current while putting a LOAD on the servos.

In other words restrict the movement a bit of at least two control surfaces as you move all of the servos at once.

That gives you a more realistic worst case.

Standard high torque servos can draw as much as 2 amps each, particularly the digital ones.