Aristo-Craft ESC?

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Re: Aristo-Craft ESC?

Post by tamiyadan » Wed Dec 21, 2016 4:04 pm

I'm just a guy that's dangerous with a soldering iron nothing more.

V12 can you elaborate on how to test and match FETs?

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Re: Aristo-Craft ESC?

Post by V12 » Wed Dec 21, 2016 6:05 pm

I was building a test circuitry for this purpose back in the days. Basically you apply a load and a gate voltage to the FET and measure the voltage drop across the FET drain and source path.
For making those measurements reliable you can´t use connectors, just solder connections. Also you have to make sure all of the load and voltage always keep the same, so no batteries but high precision power supplies or some sort of precision voltage regulation. And you have to use very good heatsink for the FET so temperature don´t rises. There is no need for long term testing but I would make sure all FETs should be tested the same duration.

For keeping things simple you need at least two digital meters, one for the load and one for measuring the voltage droop across the FET. It doesn´t make sense measuring the load right through the meter as these reading will not be really correct because of thermal influence. You have to use a shunt, maybe 0.010 ohm 25watts Dale resistor mounted to a heatsink. Measure the voltage drop across the shunt, this is much more reliable than through the digital meter directly. But measure as close to the resistor as possible otherwise heating up of wire etc. will make too much of a difference. Same is for measurement of the voltage drop across the FET, as close to the FET as possible. Not more than 1/4" away from the FET or shunt.
It´s not really important if these values are really 100% correct, they just should keep the same always. Also use a fat wire, maybe 10 gauge for connecting the shunt. Additional you need something what sets the load. Of course a constant current source would be perfect but that´s maybe too expensive. At least you need some really highwatt Dale resistors which define the current load. High amps are critical and much more difficult so I maybe would use a 10 amps load setting. I have no numbers for the load defining resistor as this depends on your power supply, load setting etc. you have to do some calculatings and trials. For Gate voltage you have to care about the max. rating mentioned at the specs sheet, this varies for type and manufacturer of FET. For the old FET I think I used maybe 12V for testing, newer logic level-FET types could be 5V or less.
Regarding connection of the FET I used a maybe 14 or 16 AWG hard wire for soldering to the FET, wires for the load and measurement soldered to the hard wire so you just have to solder the three connections to the FET and everything other keeps the same. After soldering you need to use a delay so temperatures at the FET are down before start of testing. Also mount the FET to the heatsink before doing the soldering. Make sure there is not any voltage supplied when mounting or removing FET connections. Use a main switch.

Use a switch to supply the Gate-Voltage to the FET and wait maybe 3-5 seconds then write down numbers for load and voltage drop. Actually load numbers alwas should stay the same, in this case just compare voltage drop numbers and choose those which are closest. It doesn´t make sense using a very low and a very high number together, this will drop overall performance. Also match just same type of FET, it is no good idea using different FET types at same ESC. Also no pairing of different manufacturers even when same type of FET.

This is not a 10 minutes task so actually makes just sense if there are a larger number of FETs available. Matching 6 out of 8 FETs maybe don´t make sense but at least you could make sure they really work.

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Re: Aristo-Craft ESC?

Post by tamiyadan » Wed Dec 21, 2016 6:44 pm

awesome thank you :D

i found this write up: ... mc&cad=rja

i plan to mess around in the future with making my own esc for fun.

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Re: Aristo-Craft ESC?

Post by jwscab » Wed Dec 21, 2016 8:55 pm

V12 brings up a couple if important points.

older FET styles that were not 'gate level' require a pretty high gate drive voltage. So what V12 is talking about is that you actually needed a higher voltage than the battery can supply to turn the FET fully 'ON'. so if the drive circuitry doesn't bootstrap or have a voltage doubler, the FET would not be fully on. This translates into poor performance and HEAT. Newer gate level or digital level FETs have improved structure such as TrenchFET which allows the transistor to turn on fully with a lower gate voltage.

Matching the FETs provides an even current flow through each one, which prevents one FET from carrrying a much higher load than the others resulting in premature failure. Since they are all in parallel, this is very important, and is the identical reason that battery cells are matched.

And yes, parts are manufactured on silicon wafers, and just like in grade school, the better performers get better grades and are sold at a premium. it really matters where the die is on the wafer, particularly at very high speeds. This is why you get different processors with different clock speeds.

finally, yes, all of the specs are pretty exaggerated, since trying to run any one of the esc's of the day at anything close to the ratings for extended period of time would smoke them in short order.

In fact, for guys running brushed motors and esc's with Lipo, it's very important to check temps since lipo capacity can allow you to run these vintage pieces for more than the typical 4-5 minutes from back in the day. That short time period allowed those electronics from going up in smoke.

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Re: Aristo-Craft ESC?

Post by tamiyadan » Wed Dec 21, 2016 9:19 pm

you had to watch the voltage doubler also. the FETS had a gate limit of like 18volts, so you usually had a zener regulator watching the voltage doubler.

so you had some design issues for high voltage where you needed to step down the gate voltage to under 18V or you would just blow the mosfet.

like you see limits of 4-10 cells, it was because of the gate voltage(doubler) and also the BEC voltage usually.

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Re: Aristo-Craft ESC?

Post by V12 » Wed Dec 21, 2016 10:40 pm

yes exactly what I meant. :D
The fact just is nobody used matched FETs because it´s too much work.
Matching FETs was one of the reasons my ESCs were very good and reliable.

Regarding the voltage multiplier or whatever you call this, this was the major part for deciding overall power on a given ESC. I found most commercial ESCs were very bad at this section, even those with well known names and very nice ads. Most of them were using very basic circuits just suppling 2 volts above battery voltage but not more than around 10.5 volts. This is way beyond what was possible and FET transistors used for brakes don´t really work. My own design used a massive amount of parts for this task and provided around 15 volts right at my first prototype, but this ESC was quite large. Later I used special industrial purpose circuits which were much better, much smaller and could deliver any voltage you wanted. Well there had been certain FET types which could accept way more voltage than 18 volts ... if you knew them. It worked similar to increasing turbo boost for engines, more voltage more power. :D
Regarding the zener, this was just a safety stop but in reality most ESC never reached that limit with a 6 or 7 cell battery. But voltage spikes could damage your ESC even with the zener. A very bad commutator could result in this.

Running old stuff with Lipo isn´t a good idea anyway. None of the old ESC had a Lipo safer so you also could kill your Lipo easily, not only the ESC by using too high voltage Lipo.

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Re: Aristo-Craft ESC?

Post by V12 » Wed Dec 21, 2016 11:15 pm

BTW I started matching transistors before the FET ESCs. This was when I found some industrial purpose transistors at a shop for electronic components and wanted to know how they would compare to general purpose ones found usually. Specs in the datasheet were exactly the same but these transistors looked too different so I didn´t really believe in the datasheet.
In fact these Motorola units were much better than the general purpose versions but I also found large differences between the samples. Actually larger differences than found at the FET transistors later.
But for telling the truth these industrial transistors got very low voltage drop and the early FET transistors (before the BUZ11) were not really better than those.

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Re: Aristo-Craft ESC?

Post by Lonestar » Thu Dec 22, 2016 3:20 pm

Am I the only one thinking this packaging (the box and the speedo case) look similar to some futaba products from the 90's?

AE RC10 - Made In The Eighties, Loved By The Ladies.

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Re: Aristo-Craft ESC?

Post by TRX-1-3 » Sat Dec 24, 2016 4:18 pm

Plus it's a "THORR" model. So you got that going for you. Double RRad.
Hope you're doin' something fun.

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Re: Aristo-Craft ESC?

Post by Phin » Wed Aug 16, 2017 4:00 am

TRX-1-3 wrote:
Sat Dec 24, 2016 4:18 pm
Plus it's a "THORR" model. So you got that going for you. Double RRad.
My guess is THORR was likely the name of the company in Hong Kong that actually made the ESC and Aristo-Craft partnered with them to distribute their products in the US. It'd be the same relationship they had with Hitec before Hitec started to sell their gear in the US themselves.

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Re: Aristo-Craft ESC?

Post by AscotConversion » Fri Sep 01, 2017 7:46 pm

Text of Car action review by John Rist

that defies description! — but I’ll
try anyway! The Aristo-Craft* Thorr
SP960 is the biggest mixture of good
and bad news that Eve ever seen in one

It has these features:

• forward-only with brakes, racing
style speed controller
• one FET for brakes; six for forward
• three adjustment pots: neutral, full
speed and brakes
• transparent case

spect the SP960’s ^ WJ

innards because its
case is transparent. Its ;
construction looked
first-class, but the bat-
tery and motor wires
looked small.

Aristo-Craft' s claim of
1440 peak amps seemed a
little inflated, but this is
probably the FET current
rating and not that of the
printed-circuit board or w ? ir

" A the Aristo-Craft
Thorr SP960seems to
be bulletproof f but its thin
wires should be beefed up t
{ See text J

• peak current: 1440 amps

• 4- to 8-cell capacity

• user's manual and fuse

I didn't have to open the case to in-

John Rist’s lab consists of:

• an oscilloscope

• a digital voltmeter

• a resistor load bank

• a 6V 30-amp electricity supply

• a Pit Stop Radio servo/speed
controller tester.

The oscilloscope is used to monitor
the controller’s output and to guaran-
tee that it’s fully on.

The digital voltmeter takes all the
voltage-drop readings and verifies the
reading on the current meter.

The resistor load bank consists of
40, 12-ohm, 5-watt power resistors,
which can be switched on and off one
at a time to vary the load between .6
amps and 20 amps.

In series with the resistors is a 25-
amp Simpson current meter and a 1-
percent .01 -ohm resistor. By measur-
ing the voltage drop across this resis-
tor, the current-meter’s reading can be
double-checked. Of course, the lab
power supply provides the test current.

ing. Was this the true FET cur-
rent rating? A high current rating
usually means low resistance, which,
of course, means high performance, so
I was eager to test this SC in the
“Scoping Out” lab.


After reading the instruction sheet, f
always get an SC to work on my lest
bench before trying it in a can The First
step was the installation of a fuse, be-
cause, unlike more expensive units,
this SC has no electronic thermal pro-
tection circuit. A fuse provides good
protection against burnout, but it also
reduces performance.

Next, I found a problem in the wir-
ing diagram. Two controllers were
shown: a four- wire version (two each
for battery and motor) — model no.
SP959; and a three-wire version— the
SP960. The SC I was holding clearly
had lL SP960” marked on it, but it also
had four wires slicking out of its case!
(red arid black for the battery, and red
and blue for the motor). The only
stated difference between the two mod-
els is in the waring; their peak current
and voltage-operating range were sup-
posedly the same. It seems that Aristo-
Craft planned to use a three-monster-
wire setup in the SP960 and the usual

four wires in the SP959, hut some-
where in the cost-cutting loop, the
monster wire disappeared.

The good news is that Aristo-Craft
didn't waste money on connectors.
This is supposed to be an all-out rac-
ing speed controller and, as such, it
deserves high-grade connectors like
Sermos* Power Poles. Following the
wiring diagram, I settled the hook-up
issues, and it w ? as time to set the pots
to match my Pit Stop radio servo tester
and pour on the juice.

At this point, J had a second sur-
prise: the SP960 has neither a built-in
nor an external pulse checker. The in-
structions tell you how to use a digital
. voltmeter to set full speed, and al-
though I thought this a weird way to
set full speed, it works (as long as you
have a digital voltmeter).

The final item in the set-up instruc-
tions was a warning that you should
use a heat sink if the controller is to
handle more than 10 amps (all race
cars pull more than 10 amps f). Unfor-
tunately, Aristo-Craft didn’t include a
heat-sink set, nor did it recommend a
brand that would fit. 1 discovered that
the Tekin* and Novak* heat sinks
w'Quld work wuth the SP960, but at
that point, 1 wasn't worried about in-
stalling one, because I always lest an

SC by running it “naked” to see
whether it has the guts to survive.

With the controller connected and
the full speed set, it was time to take
some voltage readings. I always take
two readings on the wires:

• first, from end to end (including the

• second, at the 2-inch point along the

The first reading establishes the SC's
stock performance level; the second
reading shows the power-robbing ef-
fect of long wires, fuses and connec-
tors, and it also provides a standard for
comparing SCs +

1 pumped 12 amps through the
SP960, and the first reading showed a
voltage drop of 0. 19 volt — a resistance
of 0.015 ohm. With 12 amps still (low-
ing, the second reading wets an amaz-
ing 0.06 volt — a very low resistance of
0.005 ohm. If you've been reading this
column for it while, you'll know that a
resistance level this low is usually
found only in the top-of-the-line, high-
buck sevcn-FET SCs. It’s interesting
that the setup with long, thin wires and
a fuse performed 3.2 times worse than
the one with 2-inch wire.

Next came my “let-it-cook” test: 1
passed a hefty 18 amps through the
controller for 1 5 minutes (without the
benefit of cooling air or heat sinks).
After this, the SP960 was warm (not
hot) and so were its battery and motor
leads. Given the small power leads and
super FETs, this is what I expected.

The FETs were doing a good job, but
the battery and motor leads were “sad.”
My final test is the “dead-short” test,
and it's designed to discover whether
the controller would survive if the mo-
tor jams or burns out. Using a shorting
device made with monster wire and
two alligator clips, 1 shorted directly
across the motor output leads. The cur-
rent-meter reading jumped to 42 amps,
and the wiring became quite warm. I

left the wire in place for 30 seconds,
and the 30-amp fuse didn't blow. You
can overload fuses quite a lot before
they bum out, and this 30- amp model
was still hanging in at 42 amps.




Height (w/heat sink)

0.75 inch


1.5 inches


.1.19 inches


...1.4 ounces


Access to Controls


Ease of Adjustment



Suggested Retail



180 days


(Manufacturer’s Specs)

Max Voltage

9.6 volts

Min Voltage

4.3 volts

Max Current Forward

..1440 amps

Continuous Current Forward

not listed


not listed



6 volts


12 amps


Voltage drop

to end of wires

0.1 9 volt

Voltage drop

at 2-inch point

0.06 volt

BEC output,

G-cell battery

6.0 volts

Resistance to end
of wires

.*0.015 ohm

Resistance at 2-inch

.’0.005 ohm

*Resistance~Voitage Drop/Amps

The Aristo-Craft SP690 has many shortcomings:
Et has no pulse checker (you set lull speed with a
digital volt-meter); the pots are misaligned (this
makes it difficult to adjust, but Aristo-Craft suggests
you use a fuse); and — worst of alt — il has the small-
est wire that IVe ever seen on a racing speedcon-
troller. Nevertheless, this controller has a world-class
low resistance that makes it a cool-running hot per-
former. High performance, smallness and low cost
make the SP69Q an excellent buy.

I removed the short and replaced the
lab’s power supply with power from a
7 -cell Ni-Cd pack. Ni-Cd packs can
deliver as much as 100 amps into a
dead short, and when I put the killer
wire back into place, the fuse popped
like a piece of popcorn. The FETs
w'ere hot, but nowhere near “melt- the-
case” hot.

To see whether the SC had sur-
vived, T reapplied power— it had ! Few
controllers are completely burnout-
proof, hut the high-grade, low-resis-
tance FETs in the SP960 are strong
enough to lake a lot of punishment.
Remember, I didn’t use a heat sink; if
you use one, the SP960 should be even
tougher. If you run the fuse, the setup
is almost indestructible.


It was time to have some fun! 1
mounted the SP960 in niy newly ac-
quired Bolink Eliminator pan car using
Scrmos Power Pole connectors on the
battery leads to match the leads on my

Then I decided to try a Corally con-
nector, which 1 discovered while doing
research for the “Connector Inspector”
article that appears elsewhere in this
issue. I had learned that the Corally
connectors weren’t suitable as battery
connectors because they can’t be po-
lar bed to prevent you from installing
the battery backwards. It should, how-
ever, be possible to solder the barrel-
shaped female half of the connector
directly to the motor brush hoods and
the male half to the SC’s motor leads.
This did, in fact, prove to be possible,
and the Corally connectors worked
well as motor connectors.

With the car set up and several
charged battery packs, I headed to the
parking lot. This setup was fast! In no
time at all, I had a dozen people
watching my bright-orange Third cut
a trail. I had deliberately geared the car
fairly high to take advantage of the
large parking lot and to push the
SP960 a little to see if it got hot. The
battery lasted about 5 minutes, which
was about right for the high gearing,

I brought the car in while the battery
had a little juice left (1 hate walking af-
ter a car!). The battery was hot, the

motor was hot, but the SP960 was only
slightly warm. I took a short break to
let the motor cool, installed a second
battery and put in a second blazing
run, during which I played wuth the
brake-control pot. I found that the
brakes could be dialed all the way out
at one extreme end, and set to normal
at the other. This could be good on a
fast roadcourse or oval where having
lighter- than-normal brakes works well.
Moreover, heavy braking is seldom
needed, even on tight roadcourses.

On this run, f pushed the car till the
battery ran all the way down. The BEC
held up well to the end, and there were
no glitching or runaway tendencies un-
til the battery was so depleted that the
car had slowed to a crawl,


With this controller, you have to be
prepared to take the rough with the
smooth. The bad news? The instruc-
tion-sheet wiring diagram didn’t agree
with the SC’s model number. (It had
the correct diagram, but it was listed as
art SP959.) The absence of a pulse
checker was very inconvenient. The
voltmeter method of setting “full-on”
worked, but it took a lot of fiddling to
make sure 1 had a solid full-on at the
80-percent trigger setting. The saddest
parts of the setup were the battery and
motor wires, which are totally inade-
quate for a controller of this size. I
don’t understand how a manufacturer
can spend big bucks on premium FETs
and then choke them to death with
chintzy w ire.

The good news? This controller is a
real performer! Its resistance measure-
ments put it in the “serious” racing
class, and it’s small and light, so it can
be installed in most [ /w- or 7 1 2 -scale
cars or trucks. Where it counts, i.e,,
low resistance and cool operation, this
controller scores high. The SP960 car-
ries a generous 1 80 -day warranty, but
Aristo-Craft lists a flock of “no-no’s”
(ranging from reversing the battery to
altering the wires), any one of which
would void it This, coupled with a
S 1 5 charge on any warranty repair,
makes the warranty a little “thin.”

This controller has a lot of potential

because: its suggested retail price of
$89.99 is quite low for such a high-per-
formance unit; if you’re handy with a

soldering iron, you could replace the poor
wire with some Stage III Super 13 wire.
Doing this voids the warranty, but at $ 1 5
a pop, l’m not sure the warranty is a treas-
ure anyway.

V d also risk a meltdown by eliminat-
ing the fuse. If you’re careful, meltdown
isn’t likely. Don’t hold the pedal to the
metal when things go wrong, i.e. if the car
quits, stop and fix it; don’t just hold down
the trigger while the smoke pours out.
Finally, I’d hard- wire the motor and use
Sermos Power Pole connectors on the
battery. Do all this, and I think you’ll have
a “trick” setup that’s high on performance
at a budget price.

*Here are the addresses of the companies men-
tioned in this article;

Aristo-C raft/ Polk y s, 346 Bergen Ave.. Jersey City h
NJ 07304.

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Re: Aristo-Craft ESC?

Post by RC10th » Sat Sep 02, 2017 1:04 pm

Wow, that was a good read. Thanks for posting !!
I was old school - when old school wasn't cool !

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