home built esc: and problem

[lostrider]

http://www.capable.ca/rcstuff/esc.htm
i have built this,
im making tests on this:without the radio;
when s1 is on: power to motor is full,

but;

i cant see any voltage on ch+ and ch- cables???
i need 5v to operate receiver&servo;
so my radio system will not work; without the power???

i cant see anything wrong soldered or soldering error??
it will work "as is"?

[Mr.RC-CAM]

i cant see any voltage on ch+ and ch- cables??? i need 5v to operate receiver&servo;You can either install a typical R/C battery (4.8V) on the Rx or add a voltage regulator to the ESC's design to act as a BEC (battery eliminator circuit). A popular Vreg for BEC use is the LM2940T-5.0.

[lostrider]

what?
this esc does not have an a voltage regulator ???????

[Mr.RC-CAM]

I don't see one. Do you?

[Dan Baldwin]

I don't see one either. The CH+ and CH- wires are 5 volt power inputs, not outputs.

Dan

[slipstick]

For an ESC with BEC try Stefan's other cct http://www.capable.ca/rcstuff/escbec.htm

Pretty similar apart from the regulator ;).

Steve

[lostrider]

i've used separate power source for radio:
but it isnt work correctly???
esc is waiting for action but doesnt have any move...
when radio off and s1 is on; gaved full power; its ok but i didnt see any action...

so i've connected my gws gs-400f to ch1; and new esc to ch3; but when new esc on ch3; all it isnt workin,
when new esc isnt connected; gs-400 workin correctly.
why?

[Dan Baldwin]

Sounds like there's a short on the 5 volt line of the ESC. Check between the CH+ and CH- with an ohm meter without either battery connected, and if you don't see a short, try hooking up the RC receiver battery (or the other ESC) for just long enough to see if the 5 volts on the receiver goes away when the new ESC is connected.

If 5 volts is connected to the ESC, the motor battery is connected, and the receiver is not connected the motor should not run when you turn S1 on. Set R8 (the pot) about half way until you get the ESC working correctly.

What kind of transmitter are you using?

Dan

[lostrider]

transmitter is gws dreamstarter,
ive found nothing, no short circuits, etc,
but second esc is worked, and new build esc is worked too;
but:!
i got only "hummm", its proportional:D
i've setted r8 trimpot,
i've checked the motor outputs and i see the voltage is here;
but when motor is connected; second esc going to red light:(low voltage?)
and dont wanna be reset, reconnecting the battery is needed.
now i will try with fully charged batteries; but this power is enough for second esc????

[lostrider]

i've connected 7cell 8.4v 750 mah nimh battery; quarter charged;
allright its working!!!
it seems to be related to power;
but i have trim problem now;???
my low-full gas arm proportion is working only % 0-10 speed???
i need a resistor- or pot change??
when arm is on zero throttle, r8 is setted to brake level;
but with this setup, when arm is full throttle, motor is turning only %10?? (with this quarter charge it can be turn much faster)

setting r8 to full ccw (higher level)=only full motor speed; proportion isnt have any effect. at lowest throttle and allready turning full speed....

[lostrider]

Q6 = irfz9540

Q2,Q3,Q4,Q5 = irfz44

[lostrider]

and receiver is gws r6nII 6 channel micro receiver,
i dont know whats the proportion resolution

[lostrider]

C2 2.2µF tantalum
maybe this is incorrect for me??

[lostrider]

oh no ive found,
r5 must be 120k, i must be right, i will try

[lostrider]

120k helped,(now i have %70 throttle)
but i dont have %100 throttle,
i added 150k as paralell to 120k, but result is %55 power,
now i will try to use 150k as single

[lostrider]

with this resistors; r8 pot proportion is limited;
now i can use %40 of this pot;
because, if i rotate to CV on zero throttle set (setting on r8),
motor did turn with full-power.

if 150k isnt work good; whats wrong??

[lostrider]

150k is helped a lot but result is the same:
i dont have full throttle???
about to %80

and 150k+100k isnt helped: result is %50 throttle..
and more resistance is effect on r8... whats wrong..

[Dan Baldwin]

If you adjust R8 so that you get full throttle when the transmitter is at full throttle, will the motor stop when the transmitter is at idle?

Dan

[lostrider]

no...
i must be set r8 while throttle is idle;
because if i set when throttle is full; i cant go to idle..

for example;
"esc's proportion is 100 unit; but my controlled area is only %60 "
related to where r8 setted;
if on idle; %40 out of control(%60 control)
but if on full throttle; %60 out of control;(%40 control)

[lostrider]

somethings must be changed, but what?
im very close to finish; only a point on r8;

out of control&%100 power
OR
controllable %80 power

[Dan Baldwin]

The problem is that that ESC is very sensitive to the type of radio it's being used with. It doesn't just use the length of the pulse being sent, it uses the proportion of the pulse to the total frame length. Your radio probably uses a different frame rate, and therefore a different frame length than the ESC is designed for. You can keep making R5 bigger (perhaps 200 K). This ESC works best with fixed frame rates. If your transmitter uses variable frame rate (I don't know if it does), you will find that the throttle will change a bit when you move ANY stick on the transmitter.

Dan

[lostrider]

no, im very close to finish but something must be changed...
replaced r7 (1k) to 2k and helped, but not completely...

[lostrider]

Q6 = irfz9540

Q2,Q3,Q4,Q5 = irfz44
maybe this components maked an a difference???

[lostrider]

current 1.1A with full throttle;
with gws gs-400f; 1.46A with full throttle..
:(

[thanhTran]

With these analog desgin, you will have to be careful with the values, input voltage, and you will need lots of patients & tools to dianostics and fix the problem. You can't just blindly replace different values of different things to see if it works. It will take you forever. I guess you need to measure the voltage at pin 5 of the Z1 of different throttle level to see if you have 1.15 volts - 1.45 volts like what the design has stated. Then check the voltage of pin 6 to see what you have. It's better to have a scope to look at the voltage in both pin 5 & 6.

I'm not sure what the voltage you use to suply to the Z1 & Q1. Is it 5 volts (CH- & Ch+) are you connected them into the RX? What's the voltage do you supply to the RX in that case?

If you need something quicker & easier: go with this:

http://microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en012017

I've built it and ported the code for 16F84. PM me if you need it. It worked fine but the resolution is not as high as the commercial one. It took me only 2 hours to port the code, breadboard the circuit and try it out on a motor and a light bulb :)

[Dan Baldwin]

no, im very close to finish but something must be changed...
replaced r7 (1k) to 2k and helped, but not completely...

R7 is not your problem, and there is no reason to change it. Either 1K or 2K should be fine.

Q6 is the brake FET, and that doesn't seem to be your problem either.

TheIRFZ44's look fine.

C2 could be a problem. The exact value of the capacitor isn't terribly important, but it must be a VERY low leakage capacitor to work properly. That capacitor is polarized. Make sure that the negative goes to CH-, and the positive goes to the comparator.

Measure the voltage across C2 (from CH- to junction of R33 and the + input of the comparator) at full throttle, and at idle, and report back with those voltages.

Dan

[lostrider]

im happy to see you in here ThanhTran :)
I'm not sure what the voltage you use to suply to the Z1 & Q1. Is it 5 volts (CH- & Ch+) are you connected them into the RX? What's the voltage do you supply to the RX in that case?
• im using GWS GS-400F on CH1 as 5v supply; and newbuilt esc is on CH3; all is working fine on this channels

I've built it and ported the code for 16F84. PM me if you need it. It worked fine but the resolution is not as high as the commercial one. It took me only 2 hours to port the code, breadboard the circuit and try it out on a motor and a light bulb
• if i can't success with this design, i will try, thanks:) but whats about resolution?

• last nigh i got a test with a 150k resistor+ 168k trimpot on r5
(it isnt 168k, but i measured as its max 168k) and i got the full speed but it isnt so nice; its going zero to %15-20 speed as sudden, %20-%100 is normal but resolution gap is so tight. i will test with 680k trimpot now.

[lostrider]

C2 could be a problem. The exact value of the capacitor isn't terribly important, but it must be a VERY low leakage capacitor to work properly. That capacitor is polarized. Make sure that the negative goes to CH-, and the positive goes to the comparator.
•I've checked again, and its on correct position.

Measure the voltage across C2 (from CH- to junction of R33 and the + input of the comparator) at full throttle, and at idle, and report back with those voltages.
•R33?=r3?

• now im building an a servo test circuit for driving this esc

[Dan Baldwin]

Sorry. Yes I meant R3 which is 33K

Dan

[thanhTran]

im happy to see you in here ThanhTran :)
....

Thanks :)
Have you measured to voltage of the pins I & Dan asked yet?
Hope you get it working soon. I'm afraid if you build a servo tester to drive this circuit and when it works with your servo tester you will have to go through the whole circle again to adjust it with your RX :D.
Thanh

[lostrider]

servo test circuit with the off-the shelf components
very simple
from modelci.net
R1=10k
R2=1M
R3=68k
R4=1.5k
R5=47k lin.pot.
C1=22n
C2=22n
C3=10n
T1=BC237
T2=BC237

[lostrider]

Measure the voltage across C2 (from CH- to junction of R33 and the + input of the comparator) at full throttle, and at idle, and report back with those voltages.
i cant measure this voltage; when i try to check; c2 is going to empty and its caused full power to motor.? maybe an a oscilloscope is needed and its bad???


I guess you need to measure the voltage at pin 5 of the Z1 of different throttle level to see if you have 1.15 volts - 1.45 volts like what the design has stated. Then check the voltage of pin 6 to see what you have. It's better to have a scope to look at the voltage in both pin 5 & 6.

i cant check??? i see only 0.20-0.25 v; or battery's voltage, and i cant find any linear voltage related to throttle, all voltage's on z1 is static.?????? how i can measure?

[Dan Baldwin]

ThanhTran and I were asking for the same thing; the voltage across C2. You should be able to measure this voltage without causing any problems. No, you don't need an oscilloscope, but you do need a DVM that has faily high input impedance. You aren't trying to use an analog meter are you?


Dan

[thanhTran]

servo test circuit with the off-the shelf components
very simple
from modelci.net
...
It's very simple and it will probably not give you the same pulse length with your RX. For even different brand of RX/TX, the pulse width is different even at the same throttle position. I used to build those things to drive leds around when I was kid. Unless you have already built it you can try using it.

Dan & I were asking you to measure the voltage between C2 (pin 5) of Z1. You said you got only 0.21 volts. Too low. What's the voltage you have between Ch- & Ch+? If you have a good voltmeter then I think you can check C1, R1, Q1, R2, R3, C2. Maybe you can also temporarily disconnect pin 5 of Z1 from the C2 and measure again to see if the voltage is different. This voltage should change when the throttle changes. The way it works (just in case if you haven't noticed) is that Q1 will close or open depending on the pulse from the RX. The longer the pulse, the higher the voltage.


thanh

[Dan Baldwin]

It's very simple and it will probably not give you the same pulse length with your RX. For even different brand of RX/TX, the pulse width is different even at the same throttle position. I used to build those things to drive leds around when I was kid. Unless you have already built it you can try using it.

Dan & I were asking you to measure the voltage between C2 (pin 5) of Z1. You said you got only 0.21 volts. Too low. What's the voltage you have between Ch- & Ch+? If you have a good voltmeter then I think you can check C1, R1, Q1, R2, R3, C2. Maybe you can also temporarily disconnect pin 5 of Z1 from the C2 and measure again to see if the voltage is different. This voltage should change when the throttle changes. The way it works (just in case if you haven't noticed) is that Q1 will close or open depending on the pulse from the RX. The longer the pulse, the higher the voltage.


thanh

Actually one problem with this circuit is that Q1 is not being used in switching/gain mode, it is wired as a follower. That means that the ESC will also be sensitive to the amplitude of the pulse; if the pulse it small, the low passed voltage will also be small. If the 5 volts to the receiver is low, the pulse will also be at a low amplitude.

Dan

[lostrider]

You aren't trying to use an analog meter are you?
• no, it is digital but its a cheap multimeter:D
• i've connected a trimpot to r5:
150k resistor+ 680k trimpot as serial, and i've setted pot's to what i can take max. power with this.

What's the voltage you have between Ch- & Ch+?
• 4.95 volt
• i've buyed a new resistor as 33k; but it seems as 38k; so i've checked my R3; it seems 32.1k; it seems normal.
6,89
5,78
c2(-) to z5 is when throttle off:0,58V
c2(+) to z5 is when throttle off;0.26V (note when i connected multimeter to this point; motor running with full power at zero throttle)

Maybe you can also temporarily disconnect pin 5 of Z1 from the C2 pin 5 of the z1 and C2??? i cant see whats related??
i've added a pic for reference; am i checked right points??

[Dan Baldwin]

Your meter is definitely way too low impedance to check the voltage on C2.

So now you can set both the pots so that you can get to full throttle, and idle?

Dan

[lostrider]

no i cant get full throttle;
but closer; about to %90..
im going to mad:D :eek: :(

[Dan Baldwin]

Are you certain that you are on the throttle channel. Have you tried plugging a servo into that channel to make sure it moves with the throttle stick? Does your transmitter have throttle end point adjustments, and are you sure that they are adjusted for maximum throw?

Recheck the values of R2, and R4. You can try changing C2 just in case it has too much leakage. You can use a lower value (like 1uf) at least for test purposes if that's all you have.

You could try using a different radio system if you have access to one, like borrow one from a friend.

At this point it would be nice to have a 'scope. I don't suppose you know someone you could borrow one from, do you?

Dan

[lostrider]

Are you certain that you are on the throttle channel. Have you tried plugging a servo into that channel to make sure it moves with the throttle stick? Does your transmitter have throttle end point adjustments, and are you sure that they are adjusted for maximum throw?
• im sure to it is throttle channel; and not its radio related;
last night i've built another esc;
its working perfectly but it isnt have throttle-off protection & bec & another special properties.
Recheck the values of R2, and R4. You can try changing C2 just in case it has too much leakage. You can use a lower value (like 1uf) at least for test purposes if that's all you have.
• yes, it can be. and last thing: making new pcb; new resistors, capacitors, diodes, desoldering the fets; ic's, and new nightwork...:(

[lostrider]

At this point it would be nice to have a 'scope. I don't suppose you know someone you could borrow one from, do you?
• surely not:D

[lostrider]

http://polly.phys.msu.su/~zeld/oscill.html
"Digital Oscilloscope Uses PC Sound Card for Input"
how is this?

[Dan Baldwin]

Using the sound card inputs would probably not be fast enough to see the signals we need to see, and I doubt that the input impedance would be high enough, although it might be fun to play with.

What kind of ESC did you build that worked fine? Is it the same one?

Dan

[thanhTran]

c2(-) to z5 is when throttle off:0,58V
c2(+) to z5 is when throttle off;0.26V (note when i connected multimeter to this point; motor running with full power at zero throttle)

pin 5 of the z1 and C2??? i cant see whats related??
i've added a pic for reference; am i checked right points??

I'm not sure if I understand what you say correctly or not.
What happens when you have the black probe connects to C2(-) and the red one connect to C2(+)? What voltage do you have when(1): 0 throttle, and (2): full throttle? Does motor runs full power when you do so? If it run full power when you do so then it's a good sign that the other parts of the circuit is working properly I think.

I'm not sure how the probes can causes this problem as the impedance of C2, R3(33K), R2(220K) is still small compared to one of my cheap volmeter.

For disconnecting pin 5 of Z1, I meant: leave Q1, R2, R3, & C2, but disconnect pin 5 of Z1B from C2. I can't see it's not related.

thanh

[thanhTran]

...That means that the ESC will also be sensitive to the amplitude of the pulse; ...

Dan
Thanks fot the info Dan. I missed this part.

Thanh

[lostrider]

thanks thanh; i will do all:)

What kind of ESC did you build that worked fine? Is it the same one?
from norbique's page;
not same esc; its working fine on 6v, 8.4v, but when im connected the fully charged 10.8V Ni-cads; it isnt working correctly... only half throttle and running on full power; no proportion:( reset needed.
norbique said "it will work with 16 cells" but it didnt run with only 9 cells....

[lostrider]

http://norbique.rchomepage.com/esc/
i have built with "buz11"

[lostrider]

when 8.4v; 22k trimpot is if setted to full(22k); motor is running with full power;

with 10.8V; its like of this.. but not when 22k is setted; when throttle is on half.and reset required.
%0-50 throttle:no power
after %50: :eek: full power

[Dan Baldwin]

You may notice that Norbique's ESC is almost identical to Stefan Vorkoetter's. The main differences are that Norbique's has an on board 5 volt regulator for the PWM circuit, it has no brake, and it uses an opto isolator on the input. If everything is hooked up correctly, Norbique's should handle high cell counts. Have you checked the 5 volts on pin 8 of the op amp with low cell count, and high cell count.

Dan

[lostrider]

ive checked::::pin 8 to battery(+)
with 7 cell: 7.2V!!!!
with 9 cell: 9.3 V!!!!

(note: cell's voltage not sure 1.2 volt; 9 cell battery is 11.5 V now)

[Dan Baldwin]

You need to check the 5 volts from the battery minus, not the plus. It should be 5 volts.

Dan

[lostrider]

ok i've checked but its only 1.68 volt with all batteries...
pin 8 to battery (-)...
i cant see the 5v?

[lostrider]

i have soldered perfectly..
i got a new soldering iron -Astron 40w from taiwan:)
and i've worked cool on this, for minimum heating to components.
p.s: i dont added norbique's patch; about two resistor changing

[Dan Baldwin]

There's definitely a problem with the 5 volts then. You'll need to make sure that the 78L05 is hooked up correctly, that there is nothing shorting the 5 volts, and that the 78L05 is good. Did you make a PC board for this ESC?

Dan

[lostrider]

yes, i have built an a pcb, i've scaled up to %115, its fitted.
and pcb's condition is very good, i've checked all copper areas with multimeter.

[lostrider]

and 78L05 is on correct position..?
my god im goinn mad

[lostrider]

...........maybe 78L05 is fryed?
its possible because i needed long soldering time on battery(+) and motor(+) points.

[lostrider]

thanks Dan;
i will replace the 78L05...
and with this problem: i have some problem too= when TX is turned off;
esc is running with full power sometimes.
maybe its sourced from 78L05

[Dan Baldwin]

This type of ESC (non micro-controller) can't tell the difference between a good signal, and noise. It could be that when you turn off the TX, the receiver is just picking up noise. Of course it's a miracle if it's working at all if it really does only have 1.68 volts on the 5 volt buss, so fixing that may make the problem go away.

Dan

[lostrider]

Of course it's a miracle if it's working at all if it really does only have 1.68 volts on the 5 volt buss,
lol yes its working perfectly on 7 cell:)

This type of ESC (non micro-controller) can't tell the difference between a good signal, and noise.
so i will need a good esc design with microcontroller, failsafe, glitch filtering, etc. i need some search again:)...


really thanks to Dan and ThanhTran, yours really good.
i have learned how i can fix the problems on electronics
• "datasheets"+"good multimeter"
or just
• "100 watt soldering iron + multimeter"+rcgroups+Thanhtran+Dan:D
(100 wat is a joke:))
also i cant fix my first built esc, but i will rebuilt on a new pcb as soon. or going for an a better design.

[lostrider]

i have replaced the 78L05; position is correct; but i see only 1.72 volt now;
and nothing changed, my god whats wrong...

[Dan Baldwin]

If the 78L05 is hooked up correctly, you have sufficient voltage on the battery connector (at least 7 volts), and you are checking the 5 volt buss correctly, there are basically only 2 possible problems; there is a large load of some kind on the 5 volt buss, or there is a problem with the meter you are using.

You have already checked all the PC traces, so it can't be a shorted trace. Have you checked after you soldered to make sure you don't have any solder bridges? You may also have a bad component on the 5 volts causing the low voltage, like a bad capacitor, or the op amp.

At this point we have already seen some voltage reading that didn't make any sense, so I suspect a problem with the meter, or with the way you are using it. I don't think the ESC would operate if it actually had 1.68 volts to the op amp. Can you give me the brand/model number of the meter, and tell me what setting you are using on the meter? Can you borrow another meter from somebody to check against your meter?

Dan

[lostrider]

multimeter is right; and old 78L05 is too; i've connected an a 8.4v battery to old 78L05 and output is 4.98V; but on a board; its with new 78L05: 1.72V

i dont have any solder bridges or short circuits; i've built it with so carefuly; and it must be run correctly... :(
I can check with another multimeter, but at this point, measurement is true..
http://www.e-sun.cn/eproductd.aspx?pht=304
Model is DT830D

[lostrider]

and with setting the 22k trimpot; on a value(i didnt measured) motor is running with full power and reset needed, but its working very good on 8.4v(7cell)
seems like to be some capacitor is going to full charge, (when i give a lot of throttle. and cant stop, reset needed) on 9 cell, and it isnt going to empty..
i dont wanna say "pot or resistor must be change"...

[Dan Baldwin]

Does the 78L05 get warm (or hot) if you leave it turned on for a few minutes (maybe 10 minutes) without the motor running?

Dan

[Mr.RC-CAM]

I've seen a few backwards LM78Lxx's on breadboards. That is because when you stand them up like soldiers, the pinout is "backwards" to what some might expect. It would be wise to double-check yours.

Here is a BOTTOM view:

[lostrider]

Does the 78L05 get warm (or hot) if you leave it turned on for a few minutes (maybe 10 minutes) without the motor running?

Dan

no, position is absolutely correct. there is no heat.

I've seen a few backwards LM78Lxx's on breadboards. That is because when you stand them up like soldiers, the pinout is "backwards" to what some might expect. It would be wise to double-check yours.

yes thanks but i've checked as standalone too and i've downloaded the datasheet for lm78L05; position is correct and its giving 5v as stand-alone

• there is a mistake, but it isnt related to 78L05 :(

[Dan Baldwin]

That is the same as is shown on the component placement diagram Lostrider worked from, so it should be right.

http://norbique.rchomepage.com/esc/complay.htm

I wonder if the 78L05 could be oscillating.

Dan

[Dan Baldwin]

Have you tried checking the voltage on the 5 volt buss without the motor hooked up?

Dan

[lostrider]

Have you tried checking the voltage on the 5 volt buss without the motor hooked up?

no, but when throttle off-or on, buss is have same volt: 1.72
i can do desoldering at this morning; if its needed
pcb & settlement is the same; on this pic(at the page) from top view of pcb


and LOOK AT THE PICTURE??!
http://norbique.rchomepage.com/galleries/esc/imagepages/img_4826.html
10µF 1 50V is must be electrolytic; but on this page;
its tantalum??????????
it must be electrolytic, on the components list??
http://norbique.rchomepage.com/galleries/esc/imagepages/img_4835.html
there isnt an a electrolytic capacitor????????????

Capacitors:
10nF 1 ceramic
22nF 1 ceramic
100nF 1 ceramic
2.2µF 1 tantalum
10µF 1 tantalum
10µF 1 50V electrolyte

[lostrider]

and on the pics; all is the tantalum capacitors...
it seems isnt finished circuit, but there is a 10µF tantalum for as 10µF 1 50V
electrolyte

[lostrider]

thats the pics

[lostrider]

o no, esc isnt with me now, thats in my office...
i remembered wrongly..
OO NOOO
I REMEMBERED NOW; IM NOT SURE BUT;
THATS MUST BE IN WRONG PLACES;
10µF tantalum AND 10µF 50V electrolyte,
i have used the pics for reference; and i see an a illusion;
i see the "100nF ceramic" as the "10µF tantalum", and i must be soldered its to wrong places;
i will check at this morning,

thats why device is working on low voltage; same valued capacitors, but wrong places...

i will write as early
im not sure, i cant did this mistake; esc isnt near of me now...
im waiting for morning...

[lostrider]

if its my mistake;
thats the reason of 1.72 volt?? how?
if its true;
10µF 10v tantalum on pin6 now,
and 10µF 50v foil on 78L05's foots...
i will replace ...

[Mr.RC-CAM]

If the 10V tantalum was operated at a higher voltage then it will be damaged. This would have occurred if it was at the other location and a 9-cell pack was used. So, do not just swap the two caps. Replace the 10V tantalum with a new part (quality electrolytic or tantalum).

Once you do this you can continue your troubleshooting safely. Prolonged over-voltage on tantalums usually results in very dangerous explosions. I've seen it for myself.

[Dan Baldwin]

The fact that you have a .1 uf (100 nf) capacitor where there should be a 10uf may be causing the circuit to oscillate. If you had a scope, we could tell for sure. The sound card oscilloscope you mentioned earlier may be of some help troubleshooting these problems.

Dan

[lostrider]

i've replaced.. but it isnt helped. buss voltage is only 1.83V;
i can use max. 8 cells........

[Dan Baldwin]

You've tested the 78L05, and you know it's good, and it is hooked up correctly. If there was too much load on the 5 volts drawing it down, the regulator would be warm if not hot (I would think), so it should be working fine. :confused:

Can you post pictures of both sides of your board?

I'm not sure where to go from here. You could try unsoldering pin 8 on the op amp, and see if the 5 volts goes to 5 volts. That would give us a place to start. Of course you can't check the voltage on pin 8 of the op amp any more. You'll have to check from battery minus to the 5 volt buss on the back of the board.

Anyone else have any suggestions?

Dan

[Mr.RC-CAM]

Can you post pictures of both sides of your board? That would really help. Quality close-up photos (same clarity as the original web project) would allow for some basic wiring verification.

Frankly, a second set of trained eyes is a very powerful troubleshooting tool.

[lostrider]

umm, ok i will try to find a good cam

[norbique]

Dear Lostrider and others,
Sorry for jumping in only so lately.

First of all, I am not an electronics engineer. I took the schematics from an old magazine and have built two of these ESC, both working fine from 6 and 8 cells. I haven't tested it above these voltages because I beleived what the text/author said in the magazine.

One advice for lostrider is to make the changes that are present on the webpage. That should be a good starting point.

Then please look at this picture at http://www.norbique.rchomepage.com/galleries/esc/imagepages/img_4838.html You can see there are three tantalum capacitors used in the circuit.

The big yellow/orange at the bottom left must not be a tantalum! Can be any simple 10u electrolyte for 50Volts. I just used a tantalum here because I could only get a tantalum that would be small (phisycally) enough to fit on the PCB.

I will check this issue with higher cell counts when I get back home and let you know of my experiences. Allow me a few days for this.

Regards,
Norbert

[lostrider]

thanks norbique:)
ps: i've scaled up to %115 this pcb, for match

[Dan Baldwin]

Looking at the schematic, the ESC should not be sensitive to cell count because the part of the circuit that develops the PWM uses a regulated 5 volts, which lostrider hasn't been able to get to work yet.

Unfortunately I'm not familiar with the characteristics of tantalums, but if they tend to have higher leakage than normal electrolytics, that is probably the problem lostrider is having with the first ESC he built. Maybe someone in the forum that knows more about tantalums can help

Dan

[lostrider]

i think my first built esc is will work in different voltage:D
i've tested it only 8.4V:) result is %80 power, not another problem
i will test this on 9 cells again:)

and second(from norbique's webpage) i will take photos as soon for yours; experts

[norbique]

Looking at the schematic, the ESC should not be sensitive to cell count because the part of the circuit that develops the PWM uses a regulated 5 volts, which lostrider hasn't been able to get to work yet.

Unfortunately I'm not familiar with the characteristics of tantalums, but if they tend to have higher leakage than normal electrolytics, that is probably the problem lostrider is having with the first ESC he built. Maybe someone in the forum that knows more about tantalums can help

Dan

Dear Dan,

You are right and lostrider should find a way to make the 5V regulator IC working right. Without that the Dual op. amp. (TAE 2453 on the schematic - substituted by an LM385P in my ESC) wont work normally. There should be the main problem.

As far as I know Tantalum electrolytic capacitors tend to have less leakage, thus have longer life (they don't loose their capacity over time as fast as) normal electrolytic capacitors. They take less space (are phisically smaller) and they cost many times the price of an identical Volt/capacity regular electrolytic capacitor.

Norbert

Added: lostrider, what voltage regulator IC are you using and what Op. amp. IC are you using in your ESC?

[Dan Baldwin]

Norbert
I assume you mean that an LM358 (shown as an alternative on the schematic) doesn't work normally. The TAE2453 is an open collector op amp, like the voltage comparator it is replacing in the original ESC. The LM358 is a totem pole output, so it will try to hold the output voltage to the 5 volt supply of the op amp instead of allowing it to go up to full battery voltage, as the open collector would, resulting in lower FET drive voltage. I'm not sure why an op amp was chosen rather than the original voltage comparator, since the op amp is being used as a comparator in this circuit.


Dan

[norbique]

Dear Dan,

I used the LM358 because I could not get the TAE 2453 anywhere. I looked up the datasheet of the TAE 2453 and made the decision on the LM358 as a substitute. It seems you know a lot more of these ICs than me. Please help lostrider solve his problems. Maybe I'm not using the right subtitute dual op. amp. Give us advice, which other IC's could substitute the TAE 2453?

I've built two ESCs using the LM358 and both work without any problems, but I would gladly switch to something better.

Norbert

[Chippie]

Guys,

A bit late in the day, but I built the esc as described with the components specified and it worked fine for me...I even used the pcb layout to make my own....

Err.. I should add that the esc was from the link earlier in the thread and not Norbique's version....


The 393 is a dual comparator with open collector outputs as Dan says...the LM 358 is a totem job...not the same! but similar to a 741......oh and yeah, tants are better but more expensive because of their low leakage current properties and package sizing...( I'm not an EE either...but can build... ;) )

[norbique]

Chippie,
Can you tell us what IC did u use in your ESC?

[Dan Baldwin]

Dear Dan,

I used the LM358 because I could not get the TAE 2453 anywhere. I looked up the datasheet of the TAE 2453 and made the decision on the LM358 as a substitute. It seems you know a lot more of these ICs than me. Please help lostrider solve his problems. Maybe I'm not using the right subtitute dual op. amp. Give us advice, which other IC's could substitute the TAE 2453?

I've built two ESCs using the LM358 and both work without any problems, but I would gladly switch to something better.

Norbert

Sorry, I misunderstood your earlier post. I thought that you were saying that the substitution did not work well. Now I see that you meant that the circuit would not work well without the voltage regulator. If the LM358 works in this circuit, then no worries.

As far as other possible substitutions, I would use an LM393 dual voltage comparator as Chippie mentioned. It has the same pinout as the LM358 and TAE2453, and is readily available.


Dan

[lostrider]

Chippie,
please give us the link of your builded esc; and please tell us how many cells do you used in your esc?
my esc is working fine, but with max. 8 cells, i dont wanna run only with 8 cells:)

and everybody; whats the next steps?

• Tantalum capacitors as for electrolytic is needed??
• TAE2453 replacement is needed?? if yes, whic IC i must use as for TAE2453?? LM393??
• now im at office, esc isnt near of me now; i will tell yours soon about what im used as IC's, and I'll post the photos of this esc

[Chippie]

Chippie,
please give us the link of your builded esc; and please tell us how many cells do you used in your esc?
my esc is working fine, but with max. 8 cells, i dont wanna run only with 8 cells:)



lostrider,
I built the same esc as the one in the link you gave...
http://www.capable.ca/rcstuff/esc.htm.
I had 8 cells on mine with no problems.

[lostrider]

yes i built this, but i can take only %80 power, i will rebuilt this on a new pcb as soon
can you try to run this with 9-12 cells?

[lostrider]

or with 7 cells?

[Chippie]

I'm not using this esc anymore, gone brushless.

The voltage/cell count is a function of load current from motor and prop combination...you may need to ugrade the fets to handle the extra current, those with a lower RdsON value...

7 cells shouldnt pose a problem as such if you use a low dropout voltage reg to supply the 5v

[lostrider]

thats the photos
dusty looking; its only balsa powder

i cant take photo from bottom, i've isolated with hot glue...

[Dan Baldwin]

I can see two differences between the parts placement diagram and your pictures. The transistor is backwards, but I assume that that is because you used a different transistor than the BC237 shown on the schematic. What transistor are you using?

The capacitor at the lower right in photo esc6.jpg (22n) seems to be in the wrong orientation. It should be running horizontal in this photo, and it runs vertical. The placement you show could only be correct if you have changed the PC layout, but since you can't show the bottom of the board, I can't tell if that's the case. That capacitor along with the 15 ohm resistor form a "snubber" that reduce the size of the high voltage spikes when the fets turn off.

All the resistor values and capacitor polarities that I could discern were correct. What op amp did you use? I can't tell from the photo.

Dan

[lostrider]

yes, it is bc237!... and its on wrong direction. my god...
but if its on wrong direction; it must be die???
i will check again, im not at home now, esc isnt here,
thanks Dan,

22n is on correct position,i've rotated 90º this legs;
i've used LM358P and 78L05 as IC's

[lostrider]

i got this correction;
its working good with 9 cells now!:)
what a bad mistake:(... i dont know how is worked with wrong optocoupler connection?? signals not cutted??...

its working but i feel its on the limits, because i've maked so much correction on pots and i found max power on pot settings: one is full CW, other is full CCW, and its rock!
i will try with 11 cells as soon.
meanwhile i've noticed about power;
its going to weak, when power weak after full run;
and i've checked batteries in this state; 9 cell is have 9.4V and i pulled max. 6 amp
but motor turning too weak.
so its looking related to power level of batteries?..

thanks to everybody!:)

and i will built first esc again with new pcb