CC Doing SHV - Page 3 - RC-Monster Forums

hemiblas · 02:15 AM

Quote:

Originally Posted by Pdelcast

Well, if you read the comments...

22A no load current is horrible. There is something wrong with the magnetic design of that motor. A motor of that size and kV should have a no-load current of around 1.5A or 2A... not 22A.

1KW of loss to eddy and hysteresis loss is just terrible.

If you think thats bad you should read the reviews on most of their HV controllers. A lot of people drop a couple hundred bucks on something that lasts no more than 1 minute. Needless to say I didnt see one good review.

When I get a chance I'm going to test my turnigy 85A vs the Castle 75 Ice and record some temps. The turnigy got to about 155 deg F in less than 45 seconds on a 40A load. I'm actually afraid to use it on my airplanes.

brainanator · 12.15.2010, 04:20 AM

YIKES!!!! this is some gigantic stuff.....wow....

V0RT3X · 12.15.2010, 10:17 AM

What would happen with the XL + 1717 on 8S in a Baja?

DrKnow65 · 12.15.2010, 10:29 AM

Vort3x, this thread is about Super High Voltage ESC's, but a few threads down is the 1/5th scale thread. You may get a better idea there :-)

P.s. I will be able to tell you what a 1518 on 8s will do in a hyper 7 soon, and 8s is too much for the 35k limit of the 1717. It's a 6s motor, 1580kv X 22.2v = 35,076 rpm

V0RT3X · 12.15.2010, 10:36 AM

Oops. I think the RPM limit is 45k though.

DrKnow65 · 12.15.2010, 11:44 AM

On my 1717 I just received from Castle it's printed "35,000 RPM MAX" right on the rear plate... I'm sure it would spin 45k for a while though :-)

lincpimp · 12.15.2010, 12:01 PM

Quote:

Originally Posted by V0RT3X

What would happen with the XL + 1717 on 8S in a Baja?

While the 1717 is a very powerful motor i do not think it is enough for the baja, unless you can make the baja alot lighter. Maybe we can start making a list of setups including vehicle weight and gearing for the various motors? That way it would be pretty easy to get an idea which motor would do well by comparing vehicle weight with a known working setup...

johnrobholmes · 12.16.2010, 11:42 AM

Quote:

Originally Posted by Pdelcast

Well, if you read the comments...

22A no load current is horrible. There is something wrong with the magnetic design of that motor. A motor of that size and kV should have a no-load current of around 1.5A or 2A... not 22A.

1KW of loss to eddy and hysteresis loss is just terrible.

We have a small group of guys trying to make the motor better for light EV use (olaf is one of them). 22a no load is in fact accurate, and it seems to be a combination of terrible ring bearings and something else going on with the controllers. They are also having a helluva hard time controlling the motor, as the low inductance and resistance is just blowing up controllers left and right. 36 TO220 FET controllers are the latest "rage". The last test:

Max RPM: 6030
Volts: 76volts
Max current: 5.5 amps
No load Power: 240 watts

They are using sensored controllers like the little legged FET versions I showed you about a year ago, Pat. To get the current this low, they had to use a timing advancer to get 48 mechanical degrees of advance at the max rpm. Maybe that gives you clues on what is going on.

My 3230 Astro is much better quality

. Too bad I got it wound for 50kv instead of 100. I will need 300v to start wringing it out

If course I didn't want it for F1 performance, I just wanted a motor that wouldn't need a ton of gear reduction to run at 30mph.

You know where to reach me Pat, I stopped by yesterday but you were gone. I got to see some goodies that really gives me hope to get these fools away from legged FET packages. I know how much you LOVE TO220 dies

Pdelcast · 12.16.2010, 11:49 AM

Quote:

Originally Posted by johnrobholmes

I know how much you LOVE TO220 dies

TO-220s have their applications... It's just not low resistance, low inductance, high voltage motors. :)

johnrobholmes · 12.16.2010, 12:29 PM

What would you consider a proper application for them? Is the thermal pathway a big enough consideration to give them an advantage on reliability or heat sinking?

Pdelcast · 12.16.2010, 12:48 PM

Quote:

Originally Posted by johnrobholmes

What would you consider a proper application for them? Is the thermal pathway a big enough consideration to give them an advantage on reliability or heat sinking?

No, there are better thermal packages today that have much better performance.

TO-220s are used where cost is the major factor. The decision to use a TO-220 almost never has performance as a major factor -- just cost. They are fine in low frequency, low performance applications with slow switching speeds. They pretty much suck for anything else.

johnrobholmes · 12.16.2010, 01:28 PM

Kinda what I figured, but the talking heads in the light electric vehicle community are sold on the legged package so hard that there is no convincing them that SMD FETs can perform at higher power levels.

So far we have found that the HV160 is good for about 6000 to 7000 watts burst on 12s with a low inductance and resistance motor like a hot 3210 Astro. Above that and the ripple voltage starts to get out of hand and things go south after about 200 miles. Things never get warm externally, but the system just doesn't like it.

Regarding the safety issues above 12s- Above 50v electricity will start to arc across dry skin. The amount of wattage available if a battery short happens becomes very dangerous. One of the members here had a bullet plug incident, I think it was 18s.

This is from one small mistake, Thanks for the pic Metallover

There are other instances of burned skin and melted systems. My buddy had an incident on 18s that destroyed his connectors, but luckily didn't spot weld them together and cause further damage. It happened in his car, he is lucky a fire didn't start.

Pdelcast · 12.16.2010, 02:54 PM

Quote:

Originally Posted by johnrobholmes

Regarding the safety issues above 12s- Above 50v electricity will start to arc across dry skin. The amount of wattage available if a battery short happens becomes very dangerous. One of the members here had a bullet plug incident, I think it was 18s.

This is from one small mistake, Thanks for the pic Metallover

That's not caused by arcing -- 50V won't arc through skin -- but it's caused by vaporized copper. When an ESC fails and the connectors vaporize, the vapor flash burns the skin.

One of our engineers here had a 6.5mm bullet vaporize in his hand, and he got 3rd degree burns over about half of his hand.

It's not really the VOLTAGE that's the issue at 50V, it's the current availability. A typical lightweight wiring harness (like for a 1/10th scale car) is about 5 milliohms -- so at 10V, the current through a short circuit is about 2000 amps -- gets things HOT QUICK, but doesn't vaporize metals instantly. A heavy duty wiring harness used with high power equipment is usually sub milliohm -- and at 70V the instantaneous current can be 50,000-100,000 amps. That will vaporize most connectors and wires almost instantly.

That's one of the "safety concerns" I'm talking about in the high voltage systems...

Thanx!

Patrick

brushlessboy16 · 12.16.2010, 03:13 PM

Sign a waiver and submit it to castle. when you process it they have to activate the esc through the Castle link.

johnrobholmes · 12.16.2010, 04:05 PM

Yes, the pic I showed were from the connectors vaporizing in his hand, not an arc from the connectors to hand. I should have been a bit more specific. Restating what I said, above 50v will conduct through dry skin. Arcing isn't the proper term.

Wasn't Jonathan's little accident caused by a large cap bank? Ever get the problem solver for that done (precharge resistorish thingies)? Cause I really want some.