No Arc Connection

[themaj]

I am working on my new Carden 89" Yak. The power system is a New 2215 with a Castle 110HV powered by a 12 Cel Power Edge Pak (2 6 cell 5000Mah in series). How do I avoid the big arc when connecting this monster

Jim

[whitecrest]

Welcome to the forum!

You could arrange your battery connection in such a way that initial contact is made through a small resistance. This allows the big filter capacitor in the ESC to slowly charge up before making the primary connection. A few hundred ohms might be about the right compromise between sufficient capacitor charging speed and arc suppression.

Another possibility that might be considered is to install a single-throw, multiple-pole arming switch. You could parallel the poles to distribute the capacitor charging current and limit potential arcing across the switch contacts. The arming switch would not have to have a massive current rating if you parallel multiple poles and because you will not be switching your working current during normal operation.

[themaj]

Thanks whitecrest...I'll give your resister idea a shot, sounds like it should work and would be a easy mod to my 6MM bullet connector system.

Jim

[whitecrest]

Originally Posted by themaj

Thanks whitecrest...I'll give your resister idea a shot, sounds like it should work and would be a easy mod to my 6MM bullet connector system.

Jim

Here is some more definitive information:
http://scriptasylum.com/rc_speed/_nospark.html

Good luck with your installation.

[kyleservicetech]

Originally Posted by themaj

I am working on my new Carden 89" Yak. The power system is a New 2215 with a Castle 110HV powered by a 12 Cel Power Edge Pak (2 6 cell 5000Mah in series). How do I avoid the big arc when connecting this monster

Jim

Per Larry3215 Posting #6, Castle Creations recommends using a one or two ohm resistor in series with the "startup" circuit. That would allow some 10 or 20 Amperes or more of DC current to flow through this resistor for a millisecond or two when the ESC capacitors are being charged.

My previous comment on this item suggested using a momentary switch. BUT with only a series resistor of an ohm or two, no reasonably priced momentary switch can handle this type of DC currents of 10 or 20 Amps. Contact welding at under these kinds of DC currents on a push button switch is a very real possibility. (Switching high level DC currents is FAR more difficult than switching high level AC currents, for technical reasons. Before retiring, I worked for a company that built 38,000 volt circuit breakers capable of clearing 16,000 Amp AC voltage faults. These same breaker contacts only had a 15 Ampere clearing rating at 24 Volts when on DC! These were vacuum contacts.)

In my case with a 6S2P A123 packs, I just keep an eye on the connector pins, and when they show a little wear, just replace them.

[Larry3215]

I dont think the momentary switch idea will work. The caps will discharge too soon. Plus I think your right - the arc could easily weld the switch in the ON position.

If you do the series resistor trick, Castle recommends only useing a 1 or 2 ohm resistor - nothing larger.

They actually prefer you leave it alone and use nothing, but a small resistor is ok.

Thats from the horses mouth

[Larry3215]

Here is the quote from Patric himself.

http://www.rcgroups.com/forums/showp...9&postcount=13

We've found that a 1 ohm resistor works quite well, and allows Auto-Lipo to work correctly.

Patrick

and a quote from Bernie Wolfard of Castle support:

Using a high ohm resistor can easily damage the ESC. Spark arrestors circuits are only to protect plugs, they are no good for the ESC. If you use a 1 ohm resistor you will reduce the spark and minimize potential damage to the ESC. HIGHER OHM RESISTORS ARE NOT SAFE FOR THE ESC. If you blow up an ESC with a higher ohm resistor it is out of warranty, it is really that simple.

Bernie

[Walt Thyng]

The latest MA has an article on this.(or was it RC Sportflyer?)
Walt

[kyleservicetech]

Originally Posted by Larry3215

I dont think the momentary switch idea will work. The caps will discharge too soon. Plus I think your right - the arc could easily weld the switch in the ON position.

If you do the series resistor trick, Castle recommends only useing a 1 or 2 ohm resistor - nothing larger.

They actually prefer you leave it alone and use nothing, but a small resistor is ok.

Thats from the horses mouth

Hi Larry3215
Using a 1 or 2 ohm resistor in series with the battery and ESC prevents the use of any simple momentary switch "precharge" circuit. So, I've changed the content of my posting.

Thanks !!!:o :o :o

[Larry3215]

Originally Posted by Walt Thyng

The latest MA has an article on this.(or was it RC Sportflyer?)
Walt

I saw one too, BUT they are still recomending higher resistor values - so DONT do it with Castle controllers.

Actually, dont do it with Schulze controllers either - they recomend against resistors as well.

[themaj]

I'll just add that I did some extensive "quiz" work with some of our Giant Scale electric guys and they all agreed...NO Resistors!

Thanks again and looking forward to participating in these forums

Jim

[Larry3215]

Yeah, like kyleservicetech said, just keep an eye on the connectors and change them out when they show wear.

Becides, your get a lot of respect from the crowd in the peanut gallery when they hear that arc welding sound

[kyleservicetech]

I'm not certain just what type of problems can result when these ESC's are powered up with series resistors. But do know that these ESC controls use microcontrollers. These microcontrollers are involved in sending the drive signals to the various MosFets that actually send the high currents to the brushless motors.

Just a guess on my part, but it could be that powering up these microcontrollers slowly with a series resistor causes the microcontroller to "Hang up". Then when the main power is connected, the microcontroller takes a short time to reboot itself. Mean while, it's driving the power MosFets. And, if the MosFets are not properly fired up, the wrong MosFets could be turned on, resulting in instant failure of the MosFets.

Pure speculation, but if it's correct, that would explain why you should never place a higher value series resistor in the circuit while powering up these units.

And, this type of failure will leave an obvious failure mode for the repair tech that fixes these units, and they can easily determine if warranty applys!

[Matt Kirsch]

Check out the "Ask AMP'D" section here:

http://www.rcuniverse.com/magazine/a...article_id=950

Greg has a pretty simple way to eliminate the arcing.

[Louis]

...

[Larry3215]

Greg's setup violates Castles recommendations as well as Schulzes. He is calling for 50 - 100 ohm resistor.

You could use his wiring diagram and just substitute a 1 ohm resistor and you'd be fine.

Note that he is using a Jeti controller. As far as I know Jeti has never spoken officially onthe arcing issue - they never comment on anything officially.

Greg is a great guy and smart as heck but Im going with the manufacturers recommendations. Seems to me the guys who make them just might know something Greg doesn't

I DO really like his idea of using the large battery disconnect switch - assuming your plane has room. Id want to check its ON resistance first, but it should stand up to the minor arcing we generate forever with no resistor. Those things are huge and the one I took apart was a wiping type connection so the arcing would only damage the leading edge of the contact area.

[Louis]

...

[Larry3215]

LOL Not nearly THAT bad I hope!

As for who said to use 1 ohm - see my post #7 above. It was Patric del Castillo of Castle Creations

Also, it doesnt just mess up the LVC settings. It can kill the esc. Bernie made it clear that you will have NO warrantee on Castle esc's if you use anything over 1 ohm.

[JAM MaxAmps]

I've asked Joe Ford about the same deal and he basically said you want the spark. No spark is not a good thing.

Jason

[kyleservicetech]

Originally Posted by JAM MaxAmps

I've asked Joe Ford about the same deal and he basically said you want the spark. No spark is not a good thing.

Jason

Hey, I grew up in Alexandria, Minn, and moved to Wisconsin after graduating from High School. Have not been to Alex in 20 years.

My wife and I are traveling to Alex the end of this month for a 50th class reunion at Jefferson Senior High!

Don't know if we'd have room for one of my models, but what kind of flying field do you have in Alex?

[JAM MaxAmps]

Originally Posted by kyleservicetech

Hey, I grew up in Alexandria, Minn, and moved to Wisconsin after graduating from High School. Have not been to Alex in 20 years.

My wife and I are traveling to Alex the end of this month for a 50th class reunion at Jefferson Senior High!

Don't know if we'd have room for one of my models, but what kind of flying field do you have in Alex?

The local AMA club is Here: http://www.alexandriar-cflyers.rchomepage.com/ It's about 8 or 9 miles north of town up HWY 29. Usually I will fly at the school two blocks away or right in my back yard in the field that is between me and the airport. Foamies at home just about anything at the school as long as you can dodge light poles to land on the running track.

Jason

[Matt Kirsch]

Originally Posted by JAM MaxAmps

I've asked Joe Ford about the same deal and he basically said you want the spark. No spark is not a good thing.

Some people, no matter how many times you reassure them that the spark is normal, cannot get used to it. The spark makes them nervous.

I think Joe's statement should be amended, "No spark [without an anti-spark circuit] is not a good thing."

If you don't have an anti-spark circuit, and a high-powered ESC does not spark, then you've got problems. It means the ESC is dead.

Adding an anti-spark circuit doesn't hurt a thing, and quite frankly there is a lot of leeway in the design. The basic premise is that you add a line that will slowly charge up the capacitors before main power is applied. 1 Ohm or 100 Ohms, IMHO, won't make much difference especially if you wait until after main power is applied before arming the ESC. All high-power ESCs on the market today are supposed to disarm themselves when no radio signal is sensed. LVC isn't set until the ESC is armed.

The process:
1. Install main batteries in fuselage, point the plane in a safe direction, secure the plane and clear the propeller area.
2. Connect the anti-spark circuit.
3. Wait several seconds.
4. Connect main power.
5. Power up transmitter and make sure throttle stick is at idle.
6. Power up receiver.
7. Go fly.

[Larry3215]

From Bernie Wolfard

Using a high ohm resistor can easily damage the ESC. Spark arrestors circuits are only to protect plugs, they are no good for the ESC. If you use a 1 ohm resistor you will reduce the spark and minimize potential damage to the ESC. HIGHER OHM RESISTORS ARE NOT SAFE FOR THE ESC. If you blow up an ESC with a higher ohm resistor it is out of warranty, it is really that simple.

Bernie

[Rodneh]

Can any of you who claim that a high ohm resistor will damage the ESC please try to explain why? It does not make sense unless there is some deficiency in the way the FET's are driven in the ESC.

[kyleservicetech]

Originally Posted by Rodneh

Can any of you who claim that a high ohm resistor will damage the ESC please try to explain why? It does not make sense unless there is some deficiency in the way the FET's are driven in the ESC.

Hi Take a look at my posting #13. Speculation on my part. But I think that Castle Creations and other suppliers are worried that powering up the ESC under current limited means could result in something getting "Hung Up". No problem yet. Until you connect the battery directly to the ESC. If the ESC has to many FET's turned on while being hung up, those FET's will be a direct short across the battery. Kaboom! And that kind of failure is easily recognized by the ESC Service Techs. And they will say No Warranty!

Before I retired, I worked for a company that manufactured high powered Electric Utility substation class circuit breakers. (Rated at 38,000 volts, 680 Amps, 16,000 Amps interrupting!) These breakers were controlled by controls incorporating computers. I taught a number of classes for our customers on the troubleshooting, repair and testing of these controls.

And one thing we found out, some of these controls did not take kindly to being powered up by a little "wall wart" type of 24 volt power supply. They were designed to be powered up by a 15 pound lead acid battery. Some of our controls were designed to run off of a substation 120 Volt DC station battery. (Those batteries can really get big!)

It took some re-design of the controls to prevent problems powering when using a little wall wart power supply for testing purposes. And, those controls cost over $6000 each.