RE: Aveox motor & ESC are weak  
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All Forums >> Electric Aircraft Universe >> Electric General Discussion >> RE: Aveox motor & ESC are weak
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RE: Aveox motor & ESC are weak - 7/5/2004 1:23:23 PM   
Matt Kirsch



Posts: 7087
Joined: 7/5/2002
From: Rochester, NY, USA
Status: offline
quote:

ORIGINAL: k1uhf
The Aveox web motor performance calculator shows that for this motor with 7 cells and a 14" X 9.5" folding prop that it should draw roughly 50 amps. A static run a bit over 11 amps. I thought maybe the prop was aerodynamically stalled so I flew it. In a medium fast motor glider the climb was only about twice as good as the old speed 600 geared motor.

How do I find out if it is the speed control or motor?


Even though this question is about a specific application, the troubleshooting can be applied to any power system.

First off, it's probably not your speed controller. Speed controllers don't limit current; the ratings indicate how much current the speed controller can take without burning up. If a motor/gearbox/prop combination is going to draw 50 amps on 7 cells, for example, it's going to draw it whether the ESC is rated for 5 Amps or 500 Amps. Speed controllers generally work, or don't.

Make sure your battery is fully charged. Many cases of power issues are caused by an undercharged battery, which can be caused by too high of a charge rate or poor quality/ too long charge leads.

Check the battery's voltage under load. If it's dropping below 1.0 Volts per cell, the motor load is too much for the battery. The pack may simply be old and tired, or it's undersized for the application. A new physically larger pack, with its requisite higher capacity, is in order.

If the battery checks out, there is a small chance that the motor is actually bad. Brushless motors can sometimes get burned windings, but that would normally cause the motor to draw excessive amounts of current, and get hot in short order.

Also make sure you're interpreting the motor's specifications correctly, and that the gear ratio in the gearbox is the gear ratio you're expecting.

(in reply to k1uhf)
       Post #: 51

RE: Ask your electric FAQs HERE! - 7/5/2004 1:37:24 PM   
Matt Kirsch



Posts: 7087
Joined: 7/5/2002
From: Rochester, NY, USA
Status: offline
quote:

ORIGINAL: LDM

Ok my first Lipo with a Trition charger ???
I just attempted to charge my 3 cell 2100mh lipo on the trition . Ok the instructions say to set the charger at 2am 11.1 volts . So I do , the chargeing starts and I watch the battery for over 90 miniutes, feeling the batrey for temp, looking at the screen ect but i just cant tell if its fully chagred .
The screen reads .
Battery type Lipo some number ????
11.21 2amps
Can someone decramble this ?
With regular flights how can I prevent flying to long and dropping this battery below nonminal voltage? My speed control dose not have a built in safty device , is there a light weight plug in product that will shut it down ?

lastly on the Triton will it shut down , or beep when the lipo is done ? wil the screen tell me ?


To "descramble" the screen, you need to post EXACTLY what the screen says, not "something like," or "something about..." The screen is showing you the progress of the charge. It's probably telling you the battery type, how many mAh it's put into the battery, the voltage measured at the battery, and the charge rate. That's pretty standard for a computerized charger with a display.

In the absence of a speed control with a programmable cutoff, a little self-discipline is in order. You'll want to time your flights anyway, so you don't run out of juice when the plane is 1000 feet away, 400 feet up, and downwind in 15MPH gusts. For your first few flights, fly a few minutes, land, and measure the battery voltage. Keep track of how long you're flying. When the pack gets down near 3.0 Volts per cell (9.0 Volts on a 3-cell, 11.1V pack), recharge. Add up the time, knock off a couple minutes for landing, and put it in your timer. When the timer goes off, it's time to land. DON'T IGNORE THE TIMER.

The Triton, like any responsible design, will stop charging and beep (if you didn't turn the beeper off) when the battery is fully charged. This should be detailed in the instructions.

(in reply to LDM)
       Post #: 52

RE: Ask your electric FAQs HERE! - 7/5/2004 2:48:39 PM   
Devin McGrath



Posts: 647
Joined: 4/24/2004
From: Rochester, NY, USA
Status: offline 		does anyone know if you can get new bearings for a 2208/34 axi brushless motor and if you can where ????

(in reply to Matt Kirsch)
       Post #: 53

RE: Ask your electric FAQs HERE! - 7/5/2004 9:40:18 PM   
LDM


 

Posts: 5299
Joined: 5/29/2003
From: Denver, PA,
Status: offline 		Matt , so you are saying that if it measures at 9 voltz total , its time to recharge ?
2) How about storage - i have read that you are supposed to store at 50% of capiacity , is that 1/2 of 11.1 voltz? or 5.5 voltz ? that woudl seam very low?

(in reply to Devin McGrath)
       Post #: 54

RE: Ask your electric FAQs HERE! - 7/6/2004 5:40:18 AM   
Hatty



Posts: 357
Joined: 10/7/2003
From: Lexington, KY, USA
Status: offline 		I was wondering why some planes have gearboxes and why others don't. What does a gearbox help with?

(in reply to LDM)
       Post #: 55

RE: Ask your electric FAQs HERE! - 7/6/2004 10:22:42 AM   
LDM


 

Posts: 5299
Joined: 5/29/2003
From: Denver, PA,
Status: offline 		hatty , I think I can helo you with this one .
A gear box can allow you to swing a larger prop. INtern gicing you more torque or pulling power and extend duration .
Some plane are set up as direct because the need for speed turning smaller props is what the modler wants.
IN the beginning many brushless motors were not set up to be geared but now many of them have gear box options .

This is just my opinion but with Brushed motors I prefer gear boxes , and brushless I prefer direct drice with no gear boxes

(in reply to Hatty)
       Post #: 56

RE: Ask your electric FAQs HERE! - 7/6/2004 1:01:21 PM   
Matt Kirsch



Posts: 7087
Joined: 7/5/2002
From: Rochester, NY, USA
Status: offline
quote:

ORIGINAL: LDM

Matt , so you are saying that if it measures at 9 voltz total , its time to recharge ?
2) How about storage - i have read that you are supposed to store at 50% of capiacity , is that 1/2 of 11.1 voltz? or 5.5 voltz ? that woudl seam very low?


When a LiPoly battery reads 3.0 Volts per series cell, it's time to recharge. At 3.0 Volts per cell, 90-95% of the capacity has been used up, and it's not worth risking damage to the battery to get that last little bit of lackluster flying in.

I have NEVER read that you should store LiPolys at 50%, only NiCds. LiPolys do not self-discharge nearly as much as a NiCd or NiMH, and can be stored fully charged, ready for your next flying session. Just keep them stored in a safe place where they won't be prone to damage. That is, don't leave them on a table or shelf where people throw their stuff.

50% charged does not necessarily mean half-voltage. On a LiPoly, 50% is halfway between the maximum of 4.2V per cell and the minimum of 3.0 Volts per cell. 50% is a little more difficult to determine on NiCd, because they hold 1.2 Volts per cell for the bulk of the charge. Normally, you need to say "close enough" or have a computerized charger to tell you how many mAh went in.

NiMH should be stored fully charged, but only because they have the highest self-discharge rate of all cell types in common use. That's so they don't go dead in long-term storage.

(in reply to LDM)
       Post #: 57

RE: Ask your electric FAQs HERE! - 7/6/2004 1:18:35 PM   
Matt Kirsch



Posts: 7087
Joined: 7/5/2002
From: Rochester, NY, USA
Status: offline
quote:

ORIGINAL: Hatty
I was wondering why some planes have gearboxes and why others don't. What does a gearbox help with?


Not a bad explanation LDM, but let me add a bit

Whether a gearbox is necessary depends mostly on the design of the motor. Some motors are designed to spin really fast and have very little torque, like Hackers. These motors can't spin a propeller of any useful size without drawing a ridiculously high current, getting hot, and burning out. These need a gearbox. Others, like AXi outrunners, are designed to spin at slow speeds and produce signifigant amounts of torque. These can spin large propellers at lower RPM.

It's desirable to spin a larger propeller at a lower RPM because it's more efficient. When swimming, which is more efficient? The dog paddle, where you make small movements very quickly, or the crawl, where you stretch out and make long, sweeping movements? Propellers in the air are very similar in behavior. A small prop spinning at 22000 RPM just thrashes the air, while a larger prop even spinning at 10000 RPM slices through it more effectively. Bigger props get a bigger, and more solid "bite" on the air.

(in reply to Hatty)
       Post #: 58

RE: Ask your electric FAQs HERE! - 7/7/2004 10:38:36 AM   
LDM


 

Posts: 5299
Joined: 5/29/2003
From: Denver, PA,
Status: offline 		Matt , thanks for the data , I have one last question . Ok If I have a 2100 mah /11.1 volt lipo batery why is it charged fully at 4.2 volts per cell =12 .6 voltz max - The battery says ita a 11.1 volt battery . I know this is a stupid question but if you look at this in simple terms not knowing that the lipo max per cell is 4.2 , common reasoning would tell me that it is fully charged at 11.1 then each cell should read 3.7 x 3 =11.1 . I know this is wrong but this is why I am having such a hard time making it easy .

(in reply to Matt Kirsch)
       Post #: 59

RE: Ask your electric FAQs HERE! - 7/7/2004 12:45:29 PM   
Matt Kirsch



Posts: 7087
Joined: 7/5/2002
From: Rochester, NY, USA
Status: offline 		All batteries are rated at their nominal voltage. Nominal voltage is always somewhere in the middle of the working range of voltage, often times where the battery spends the most time during discharge.

LiPoly is rated at 3.7 Volts per cell, but its working range is 3.0 Volts empty to 4.2 Volts full.
NiCd and NiMH are both rated at 1.2 Volts per cell, but working range is 0.9 Volts through 1.4 Volts.
Alkaline batteries are rated at 1.5 Volts per cell, but they measure closer to 2 Volts when brand new, and less than 1 Volt when depleted.

(in reply to LDM)
       Post #: 60

RE: Ask your electric FAQs HERE! - 7/13/2004 2:55:08 AM   
sprint2x@aol.com


 

Posts: 1
Joined: 7/12/2004
From: , OH, USA
Status: offline 		I'm new to electrics, ordered my first foamie 3D, brushless motor, ESC, LiPo batteries, etc. Non of the literature provided by the manufactures showed a wiring schematic or explained very well how to wire the components. My ESC does not have separate leads for an on-off switch, so to add one I'd have to wire it directly between the battery and ESC. Is an on-off switch recommended (adds weight) or is it safe and practical to simply plug the battery connector into the ESC to power up?

(in reply to ConfessChrist)
       Post #: 61

RE: Ask your electric FAQs HERE! - 7/13/2004 3:18:01 AM   
photors



Posts: 6
Joined: 9/12/2002
From: Dover, DE, USA
Status: offline 		I have noticed in lower voltage packs 7.2- 9.6 Volts that the NiCad and NiMh packs are not the same. It takes 1 additional NiMh cell to give the same performance as a NiCad pack. Is this peculiar to low voltage packs or is it a rule of thumb that NiMh cells do not produce the same dynamic voltage as NiCad's ?
Robert Samuel

(in reply to ConfessChrist)
       Post #: 62

RE: Ask your electric FAQs HERE! - 7/17/2004 4:10:17 AM   
yellerchamp



Posts: 223
Joined: 7/3/2004
From: mcleansboro, IL, USA
Status: offline 		Question about electric, after flying glow thought I would try a electric, bought a scratch and dent from tower. It had a busted firewall, I repaired charged it up and hand launched it in to the wind. Another cracked firewall, at full throttle with factory t600 and new 8cell nicads it cant hold itself in the air, looked at gear boxes but with the extra cost is it really worth it, oh yeah tried 3 different size props, this is a hobbico superstar ep 8 cell t600 mtr .

(in reply to photors)
       Post #: 63

newb ???s - 7/24/2004 5:35:57 AM   
ptrpilot


 

Posts: 4
Joined: 7/11/2004
From: Alexandria, VA, USA
Status: offline 		hi to all. considering getting into the hobby. no previous exp. have read elec helos are considerably harder to fly than nitro. should a newb start w/elec helos? any suggested reading materials? i want to buy a sim to learn the basics. any suggestions appreciated. tia.

(in reply to ConfessChrist)
       Post #: 64

RE: Ask your electric FAQs HERE! - 8/2/2004 7:07:22 PM   
sprintdawg007



Posts: 46
Joined: 8/1/2004
From: Burke, VA, USA
Status: offline 		Ok, I've got a question, or a bunch actually. I'm a complete Newbie at RC Flying.

Is there a glossary somewhere that I can pick up on all the terms you guys shoot around?
I know RTF, ARF, and I can figure out most of the battery short names because I took Chemistry and know the elements. But how about Tx, Rx, stuff like that? Any help would be greatly appreciated to help me get knowledgeable about the topic.
Thanks in advance guys,

~a.C.

< Message edited by sprintdawg007 -- 8/2/2004 2:07:55 PM >

(in reply to ptrpilot)
       Post #: 65

RE: Ask your electric FAQs HERE! - 8/2/2004 7:13:25 PM   
Hatty



Posts: 357
Joined: 10/7/2003
From: Lexington, KY, USA
Status: offline 		You can just search for RC