Electromagnetic clutches are popular on a variety of mobile applications. The clutch engages the hydraulic pump, water pump, vacuum pump, or compressor, when that accessory is needed. These are common on tow trucks, snow plows, service vehicles, ambulances, refrigeration trucks, pressure washers, construction equipment, and more.

It is important to size the clutch for the torque required by the pump. If the clutch is undersized, it will slip. Slipping can cause massive amounts of heat and heat is the worst enemy of a clutch. A slipping clutch can gall the friction surfaces and actually weld them together so that the clutch stays engaged without power being applied.

Torque is dependent upon pump displacement and pressure. When torque is unknown, there is a reference calculation to consider for torque.

Furthermore, most clutches are not burnished to achieve full torque transfer capacity when first installed. To achieve full torque capacity on the clutch, it will need to be burnished. Burnishing will wear the clutch in and help prevent slipping when the clutch is run close to its catalog limits.

Keep in mind that clutches are rated for static torque as an industry standard. When engaging dynamically, you have to account for the dynamic torque rating of the clutch. Dynamic torque ratings can be 50-60% of the static rating when run at normal RPM, so keep that in mind when selecting your clutch. Ogura's Application Engineers can also offer assistance when needed.

For smaller pumps and engines, the Ogura MA Series clutches are available in torques ranging from 58 to 175 lb. ft. For pumps requiring higher horsepower, the MMC Series are rated from 200 to 1500 lb. ft. A variety of bore sizes and pulley options are available from stock.

Benefits of using an Ogura mobile and general purpose clutches:

• Long life
• Safety and convenience with remote starting
• Fuel and energy savings
• Built for outdoor operation
• Many years of proven success
• Custom designs available based on minimum order quantities
• Reduced engine load on cold weather starts
• Increased operational life of driven equipment
• Simple installation

---

---