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PMA's <Std. Series>      Super Core PMA's

Friction Drive Roller

These will solve many problems for wind turbine designers and open new doors of opportunity for others looking for remote and portable electric power generation! Includes fan kit. (Not shown)

(Great for regenerative braking on H2 or electric car tires)

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


For more traction use rubber!
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 Drive RollerFriction 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)

PMA's <Std. Series>
Super Core PMA's