Jeti 200 sparking...

[hcuellart]

Hello guys,
My Jeti/HackerMaster 220 is sparking, even though I connect the antispark cable to the lipo first... The manual is not very clear here :confused: , should I have to wait for some time for the capacitors to charge before I connect the main positives?
My sequence is the following:
First connect the negative (black) cables, then I connect the red antispark small bullets from the ESC to the positive side of the lipo (small red I installed on the lipo) and finally the two main positive bullets...
Maybe I should wait or is my antispark capacitor bad??
Well any help is much appreciated ;) !!
Thanks,
Homero

[eye4wings]

There's a thread somewhere that discussed the sparking issue fully and the way to get round it is to connect a shunt through a 1/2W 50ohm resistor on the live side.
You're right in saying the spark is caused by the charging of the ESCs capacitors.
The connection process then becomes...
1. Connect Negative power line.
2. Connect live shunt - wherupon the current passing through the resistor charges the capacitors.
3. Connect live power line - NO spark!

Sparking is normally only a problem when using bigger stacks of cells, but this works for any and all and is easiest with 'bullet' connectors.

[hcuellart]

There's a thread somewhere that discussed the sparking issue fully and the way to get round it is to connect a shunt through a 1/2W 50ohm resistor on the live side.
You're right in saying the spark is caused by the charging of the ESCs capacitors.
The connection process then becomes...
1. Connect Negative power line.
2. Connect live shunt - wherupon the current passing through the resistor charges the capacitors.
3. Connect live power line - NO spark!

Sparking is normally only a problem when using bigger stacks of cells, but this works for any and all and is easiest with 'bullet' connectors.

Thanks, in fact the Jeti 220 has an integrated spark arrestor feature with an integrated capacitor to the ESC, what confuses me is that it is not working properly...

[Magne]

Yes, there has to be a time delay for the capacitors to charge, that's the whole point of the resistor. Only a second or two, though. (depending on the resistor)

Magne

[hcuellart]

Well I've left it for 30 seconds or more and it still sparks... :confused:
Still have not received an answer form Aero-Model about the problem...
Thanks Magne! :D

[Tipover]

I'd try putting a digital voltmeter across the plus and minus battery terminals. Then apply power between the minus battery and anti-spark wire(small red wire). See if the voltmeter shows any slow or partial charging. Sounds to me like the anti-spark charging resistor is open circuit. You could also check the resistance between the anti-spark wire and plus battery terminal. Should read some resistance around 100 ohms. 100 ohms is what I read on my Hacker/MasterSpin 170.

If for some bizarre reason that resistor is open, or wrong value (or they just forgot to put it on the circuit board), you can touch a 100 ohm resistor in series with the plus battery terminal before direct connection of your plus battery wire. That’s how simple the anti-spark circuit is. They just added a series resistor and another red wire.

The fact that you are getting a spark tells me that your filter caps are likely good, and, there is more than one cap in parallel across the battery supply input. Does your speed control work normal otherwise, besides the spark during hook up?


Kevin

[hcuellart]

I'd try putting a digital voltmeter across the plus and minus battery terminals. Then apply power between the minus battery and anti-spark wire(small red wire). See if the voltmeter shows any slow or partial charging. Sounds to me like the anti-spark charging resistor is open circuit. You could also check the resistance between the anti-spark wire and plus battery terminal. Should read some resistance around 100 ohms. 100 ohms is what I read on my Hacker/MasterSpin 170.

If for some bizarre reason that resistor is open, or wrong value (or they just forgot to put it on the circuit board), you can touch a 100 ohm resistor in series with the plus battery terminal before direct connection of your plus battery wire. That’s how simple the anti-spark circuit is. They just added a series resistor and another red wire.

The fact that you are getting a spark tells me that your filter caps are likely good, and, there is more than one cap in parallel across the battery supply input. Does your speed control work normal otherwise, besides the spark during hook up?


Kevin

Thanks for the advice Kevin, I will try with my voltmeter the resistance but I am sure it is open... I think I will have to go to the homemade 100 ohm resistor route...
Other than that the ESC is working perfectly, though I am having trouble getting correct max amp draw measurements from the esc. I am getting really strange numbers.
Are you getting the correct measurements from yours? I have read that I might have to be at full throttle for at least 15 seconds to get a correct amp draw measurements...
Again thanks for the tips.

PS Just to be sure you are 100% sure it is a 100 OHM resistor the one I should get?

Best regards,
Homero

[Tipover]

Other than that the ESC is working perfectly, though I am having trouble getting correct max amp draw measurements from the esc. I am getting really strange numbers.
Are you getting the correct measurements from yours? I have read that I might have to be at full throttle for at least 15 seconds to get a correct amp draw measurements...

Strange readings seem to be the norm. One of the tech guys at Hacker USA told me I would need a 15 second max run to get a good reading. IMO not very useful as peak current reading, especially if we are over propped for max current. I guess we can still use it as a relative benchmark while comparing various props, but a clamp on current meter seems to be the preferred method of getting an accurate current reading.



PS Just to be sure you are 100% sure it is a 100 OHM resistor the one I should get?


The resistor on my Master 170 reads 99 ohms with my Fluke meter. Should not be a critical value. Its just used to slow the inrush current to the filter capacitors.

Kevin

[hcuellart]

Will try and use a 100Ohm resistor to stop the huge spark, not that I am scared of it, but I guess my connector even though they are 8mm bullets are getting a beating...
Thanks again and best regards,
Homero

[eye4wings]

Sorry guys - just back from holiday!

http://www.rcgroups.com/forums/showthread.php?t=987819&page=2&highlight=sparking+connection

That link will give you a pretty full discussion of the problem.

However I heard just before going away that there may be a problem with some ESCs using the resistor bypass loop if they automatically sense the pack voltage in the early milli-seconds of connection. In that event, too large a resistor MAY cause the ESC to decide too early that your pack is a cell less than it actually is and set the auto shutoff too low - killing the pack.

It would only do that if the resistor failed to charge the capacitors quickly enough, so a smaller value of resistor is advisable. The trick is to balance the current flowing through the resistor so that it is low enough to eliminate the spark while being high enough to avoid sensing problems. A larger wattage of resistor is required as the resistance decreases. One contributor to the above thread used a too low-rated resistor and blew it the moment he connected it - and still had the spark!
27 ohm or 33 ohm resistors are about right BUT they MUST be at least 0.5W rated to survive.