Frequently Asked Questions

The Cyclo speed reducer, by virtue of its smooth, almost frictionless operation (unlike traditional helical gears), has a thermal rating that far exceeds its mechanical capacity, and all but eliminates the conventional limitions due to heat.

The standard ratings for Cyclo are based on 10-hour daily service under conditions of uniform loads (equivalent to AGMA service factor 1.0). By following the product selection process outlined in our catalog, you will determine and apply the Service Factors to compensate for the severe operating conditions.

To select the proper reducer for your application, you need to know: Application: type of driven machine 
Hours of operation per day 
Motor horsepower (HP) and speed (RPM) 
Mounting position 
Ambient environment (altitude, dusty, chemical, explosive, water) 
Ambient temperature and humidity 
You must also note any special environment factors or operational requirements. This information will be important in determining your application's service factor.

In general terms, the speeds are 1750 and 1165 RPM. The selection tables in our catalog are based on 1750, 1165, 870, 580, and 50 RPM. When non-standard input speeds are used, the kilowatt (or horsepower) and torque ratings also vary.

This is because Cyclo has a high teeth engagement rate. Since the Cyclo gearing has two-thirds of its reduction components in contact at all time, it can withstand higher shock loads and is more stable than traditional involute gearing.

Cyclo^® is a type of internal planetary gear. The planetary gear has cycloidal-shaped teeth. All torque-transmitting parts roll, not grind. Unlike the normal involute teeth with limited contact points, a Cyclo has two-thirds of its reduction components in contact at all times. Multiple teeth share the load, so therefore the Cyclo^® is not susceptible to tooth breakage.

Models having an "N" after the nomenclature symbol "C (Cyclo)," are universal mounting models that can be mounted in any direction . However, when there is an "H (horizontal)," "V (vertical with slow speed shaft downward)" or "W (vertical type with slow speed shaft upward)," after the "C," the unit cannot be mounted in any direction other than the one specified.

Mounting bolts are not included. Refer to the maintenance manual for mounting bolt specifications.

Cyclo frame size 606 to 612# are called “MF: Maintenance Free.” Grease replenishment is not required for normal operating conditions, and grease fittings are not utilized. Sumitomo recommends overhaul and grease change at 20,000 hours or 4-5 years. However, when the Cyclo uses special grease for high or low ambient temperature and grease fittings are installed, then grease replenishment and grease changes are required according to the appropriate factory schedule.

Generally, Cyclo^® Drives allow for input at 3600r/min for up to 3HP, 6:1 to 87:1 ratio. For more than 3HP, it varies depending on frame size and reduction ratio. Many Cyclo models can accept input speeds of up to 3,600 RPM. However, the maximum allowable input speed is dependent upon the model number and the reduction ratio.