Made of hardened steel with a rough knurled finish
for extra grabbing power on rubber tires.
Steel Drive Roller - Rated for
3000 Watts of maximum traction grip for #SCS PMA's
For use with SCS -split-core PMA's
ONLY
Model #DR1
$69.95
For more traction use rubber!
NEW HEAVY DUTY 100% SILICON RUBBER!
VERY TOUGH!
Drive Roller - Rubber Coated
For use with SCS
-split-core PMA's ONLY
Model #DRR160 - 1.60" diameter drive roller
only $199.95
Rubber roller provides good traction
on steel, wood and plastic wheels.
Also works well on rubber tires in applications that produce
high amperage loads.
To keep rubber rollers soft and generally in peak condition
treat them with "Penetrating Oil/Fluid" once a
year. Well maintained rollers are stickier which provides
for superior traction. Penetrating oil or fluid can be found
at any auto parts store. Rubber roller life span is about
30 years if well maintained.
Create electricity from any type of rotating tire or wheel
!
Can't figure out how to get enough RPM's from your wind
turbine to power your PMA? Now a 40/1 gear ratio is EASY
!
Gears, chains and pulleys all have their own unique
problems! Noise and the constant need for lubrication are
just a few of those problems that our new friction drives
have eliminated. Friction drives are VERY inexpensive and
very dependable !!!
Friction
drives use ordinary rubber tires as the main gearing mechanism.
Gear ratios of 40 to 1 are easily achieved using cheap mass
produced rubber tires. Many types of rubber tire hubs are
also equipped with brakes so over speed protection is very
inexpensive and in many cases built right in to the hub!
We have used trailer tires with electric brakes, golf carts
tires, buggy and carriage rims, motor cycle and even bicycle
tires. Don't worry about flats as there are few nails or
thorns floating around in the air. Tires can also be urethane
filled and then balanced at your locate tire shop for only
a few dollars. Our roller drives have brought new life to
many Darrieus turbine designs and other VAWT's with a horizontally
mounted tire drive. Any slow turning turbine design can
benefit greatly from roller drives and fast turning wind
turbine designs can be turned into really powerful machines!
With a roller drive system its easy to get your PMA's
spinning at well over 10,000 RPM without very much work
or expense. Our rollers have a 7/8" OD and are 3"
long. They have a 17mm ID thread that fits right on all
our standard PMA's. We recommend
using some type of industrial strength thread locking adhesive
so they can't come off of the shaft unless you want them
to. The best trick is to design your system to keep the
roller spinning clockwise (Always tightening).
Advantage
ratios are easy to figure out.
This 20" tire has about 62.8"
of surface length per rotation
(20" x 3.14) so with our roller you will get an output
ratio of about *23 to 1 at your PMA shaft. Impressive !
This means if your wind turbine is rotating at a mere 500
RPM your PMA will be screaming at about 11,500 RPM!!!!!!!!!!!!!!!!!!
That's very useful advantage ratio for a drive mechanism
that anyone can pick up at a junk yard for only a few dollars!
Just make sure you purchase the
correct PMA model so it is never over loaded!
A high amperage load at 500 RPM could smoke your tire
so a little R&D may be required to get the right combination.
These systems are NOT recommended for variable speed applications.
They do however work rather well if you have a fairly consistent
tire speed.
Roller and tire friction drives are also very silent unlike
gears and chains plus they never require any type of lubrication
or maintenance. We figure that a tubeless tire designed
to handle 500 lbs. for 50,000 miles ought to last about
30 years+ under the minute amount of stress that a roller
friction drive demands and that's the best news wind turbine
designers have heard in a long time!
Tech Notes:
Remember that a drive roller MUST have spacers on the shaft
between the bearing and the roller to keep the rotor shaft
from moving back and forth within the PMA housing!!!!!!!!!
- Drive roller includes a 15/16" hex nut head (not
shown) that needs to be driven on the PMA shaft with an
impact gun. If you let us know when you purchase the roller
and PMA we will install the drive roller onto the PMA
for you.
Design notes:
If
you design your mounting arm to pivot closely to the "center
of rotation" the roller will get tighter as the RPM's
go up and it will loosen as they go down providing "living"
roller pressure. This is important as you would not want
to have to much roller pressure dragging the turbine down
at low start up speeds. As the tire spins faster and faster
the PMA starts to create amperage causing the roller to"drag"
thus pulling downward against tire harder and harder making
more solid roller contact at precisely the time it is needed
most and all because of the ingenious way this simple pivot
design reacts to the rotation of the tire. The closer to
the center of rotation you place your arm the more pull
down or contact power this design will transmit to the roller.
Be careful because if you design your pivot arm to be overly
close to the center of rotation you can create so much pull
down pressure that things start to get inefficient and also
tire pressure can become overly critical. As a general rule
a friction drive must be used with a heavily inflated tire
so that the contact interface is extremely hard! A soft
or mushy interface can be very energy inefficient.
The illustration below shows the arm placed in the "sweet
spot" which is about 50% of the way between the center
of rotation and the outside of the tire itself. This is
what you should aim for and is exactly how we are going
to be building our new Blue-Max Turbines when they are reintroduced
in July of 2004. Testing is going VERY good!
*More math (.875 X 3.14 = 2.7475 <rounded>
2.75 then 62.8 ÷ 2.75 = 22.8 RPM <rounded>
23)
