Contra Angles Gear Ratio

Contra angles like the Kavo 25 LPA above come in varying speeds and may be driven by electric or air driven low speed motors. The illustrated picture shows a 1:5 arrangement which increases speed at bur to 5 times motor speed. For every time large gear at bottom spins, small gear with shaft continuing to the contra angle cartridge, spins 5 revolutions, thus resulting in speeds approaching 100,000 rpm from a standard 20K air driven motor. Of course many electrics operate at 40K, resulting in 200,000 rpm from 1:5 speed increasing contra angles. Contra angles capable of these type speeds require near perfect meshing of precision gears, manufactured to space age tolerances.

E-type Contra Angles Provide Choice

Dentists wishing to sample a little of what Kavo offers might consider purchasing a standard, non fiber optic, contra angle which does not require water spray to couple with their standard E-type air driven or electric motor. This can provide a low cost alternative to a complete 1 brand setup. Careful though. If you’re use to a 20K motor driving 1:1 contra angles, speed increasing contra angles can require a little extra practice. Of course, you’ll need a Kavo motor with fiber optics and water spray capability to run a contra angle such as the Kavo 25 LPA. The Kavo ELECTROtorque is compatible.

E-Type Motor to Contra Angles Connection

Kavo employs the European (E-type) connection commonly used by manufacturers world wide. E-type connections are also used by W&H, NSK, Athena Champion, Nakamura, and others. Star Dental and Dentsply Midwest employ their own patented connections. The E-type connection provides a very efficient and trouble free method of combining multiple components, ensuring proper mating of gears. The tube type coupling provides an ample surface to surface mate, held stable and vibration free by well placed o-rings and/or spring clips. Contra angles with ratios of 1:1, 1:5, 1:7, 2:1, 10:1, & 16:1 are common combinations which allow desired speeds to be maintained while being driven by a standard 20,000 rpm motor. Be careful though, speed increasing contra angles with water spray typically require same brand motors.