BRUSHLESS MOTOR SYSTEM
Written by: Martin P. Manahan,M.D
The January 2001 issue of RCCA announced
that Novak was releasing a brushless motor for electric touring
cars this summer 2001. Novak promised that the brushless motor would
provide a 25% jump in efficiency, with more power, and zero maintenance.
For those of us who race in modified, this bit of news was revolutionary
and tremendously exciting to say the least.
I tried to get information by posting
questions on Trinity Tech Talk, but I noticed that my posts where
removed within minutes of being posted. This Phenomenon was not
limited to my posts, but to all posts pertaining to brushless motors.
I decided that the people at Trinity were Dim Witted Nazi’s
and decided to start a thread on RC Touring entitled Novak Brushless
Motors. I asked whether there was a brushless motor and controller
that were made for TC’s, and a very knowledgeable Portuguese
gentleman by the name of Antonio Pirespreto (His web page is a fountain
of information on most things RC, you can find it on http://www.pirespreto.com/gstarted.htm)
informed me that there was a company in the UK that produced a brushless
motor and controller specifically for electric touring cars, and
this company was Modeltech. I went to the site with the URL http://www.gtdodd.demon.co.uk/index.htm,
and I was immediately impressed. The units they produced all were
controlled by a controller, which could accommodate 4-12 cells,
with a limiter of 100,000 rpm. The motors were rated at 600 watts
power, and were produced in 4 types: the B 46 was rated at 7,100
rpm/volt; the B 47 was rated at 6,087 rpm/volt; the B 48 was rated
at 5,325 rpm/volt; and lastly the B 410 was rated at 4,260 rpm/volt.
Considering the fact that the Guinness Book of World speed record
of 111mph for RC set by Cliff Lett was done using an Aveox motor
with a rating of “only” 3,500 rpm/volt, the numbers produced
by the Modeltech motors were incredible.
I realized that I did not have to wait
until Novak released their brushless motor the later part of this
year; here was a system I could get by mail order! There was, however,
one caveat- the combination of motor and controller cost the equivalent
of 17,000 pesos! The latter fact did not sit well with me, but then
it got me to thinking: if I sold all my motors, my controllers,
and my comm. Lathe, I would have more than enough money to buy the
system with a lot of spare change as well. Little by little, I sold
some of my equipment, and when I came up with enough cash, I placed
the order online for the B46 system. I did not want to have to wait
so long so that I had them ship it to me via DHL. For 3 days I held
my breath. When the unit arrived, I was immediately impressed by
the quality of the product.
The unit comes with it’s own special
yellow carrying case, and the first thing I remarked on was that
the motor itself was so small! The dimensions are 2.8cms diameter,
and 4.7 cms long without the wires. It was also very light at 125
grams. The controller was different in dimension from a normal ESC,
but just as light. One cannot help but notice also that there are
3 wires instead of the usual 2. The wires were extremely thick (gauge
10?) and obviously designed to carry a large amount of current.
Mounting the motor was very easy on
a TC3, which was the car I was using at the time, but the controller
simply could not fit on the chassis, so that I had to mount it on
the battery bar.
TESTING
Now that the system was mounted on
my TC3, I rolled it without power. There is no resistance from the
motor and the car basically freewheels. I did not have the proper
gearing, so I decided to gear the car low. I started with the recommended
gearing for 5 turns (I extrapolated from the manual since no such
commercial motor exists to my knowledge) then held my breath as
I slowly squeezed the throttle. The results were frightening: the
car has nearly no spool up and the curve is flat so that top speed
is achieved within 4 meters. My HPI 33R tires squealed initially,
and started chattering. The car took off like a bullet. It was obvious
that I had to use stiffer springs. At the end of the street, I applied
the brakes, and the car spun to a halt. The brakes are a powerful
as if one were using a nitro with disc brakes so that I had to dial
out my braking exponential to –70% in order to get it to brake
like a normal brushed motor and ESC. I changed the gearing to an
8-turn equivalent, and decided to give it a spin at the large track
at Park Square. The car flew around the track like a rocket, and
I could barely control it, Modeltech suggests that you gear it like
you would a 12 turn motor, and I think that they are right. On my
lousy practice 3000 Panasonics, I did nearly 12 minutes with the
TC3. Motor temperature measured at the end of the run was at 42
degrees centigrade, which is very cool by any standard, especially
considering I was using the TC3, which tends to run the motor very
hot (about 70 degrees centigrade, or hotter).
Was it worth 17,000 pesos? Of course!
I sold some extra stuff, and came up with the amount. Other things
I sold and which I did not need were extra brushes, and my Robitronics
dyno. At the end of this escapade, I had a lot of extra cash from
selling, plus I looked forward to saving a lot of money and trouble
not having to maintain and replace mod motors; I could also use
my old 2000 packs to run more than 6.5 minutes so that I did not
have to buy any new 3000 packs.
Modeltech has made great strides in
building the first competitive brushless system for electric touring
cars, yet I look forward to the emergence of the Novak system as
well, because that will eventually bring the price down and make
BL systems acceptable to the sanctioning bodies. The brushless systems
because of their zero maintenance and frictionless operation are
a big threat to established companies like Trinity, but they are
a boon to those of us who have to buy our stuff, because in the
end, we save a lot of time, and money, and we have the pure motor
power to leave the likes of Barry Baker and Masami Hirosaka in our
dust, at least when drag racing. I fearlessly predict that within
a year, all of us who race mod will be running with brushless motors-
Onward with the brushless revolution!
