Grease for sliding electric switch contacts must meet similar demands as other mechanical sliding surfaces: film strength, appropriate low and high temperature fluid range, and stay-in-place capability. In particular, a switch grease’s ability to prevent wear is critical. Wear debris creates two problems. It can inhibit current flow when the contact is closed, increasing millivolt (mV) drop. When the contact is open, conductive wear debris can cause open circuit resistance (OCR) problems. In either case, switch performance is compromised. When selecting a switch grease, also note that the viscosity of the base oil should complement the contact force of the switch. Low current/low contact force applications require lighter base oils. High current/high contact force applications benefit from more viscous base oils.
|Product Name||Temp Range (°C)||Rec Contact Force (g)||Up to 1 Amp||1 - 10 Amps||Over 10 Amps||Product & Application Notes|
|INSTRUMENT GREASE 732C||-54 to 150||20||*||*||Light viscosity, polyolester grease intended for electrical switch contacts. Wide temperature range. Salt water resistance, copper deactivator and EP fortified.|
|RHEOLUBE 362HT||-54 to 125||50||*||*||Light viscosity grease intended for electrical switch contacts. Enhanced temperature stability, plastic compatible. Rust inhibitor.|
|RHEOLUBE 368||-40 to 125||150||*||Medium viscosity, grease for sliding surface applications. Cost effective. Plastic compatible.|
|RHEOLUBE 716HT||-54 to 175||20||*||*||*||Light viscosity grease intended for electrical contact applications with extended high temp exposure. UV tracer.|
|RHEOLUBE 737S||-60 to 120||20||*||Very soft, light viscosity grease for electrical applications requiring low torque at low temps. Salt water resistance. Plastic compatible. Copper deactivator.|
|RHEOLUBE 789DM||-40 to 150||80||*||*||Light viscosity ester grease intended for electrical contacts requiring wide temperature serviceability. Good water resistance. Plastic compatible. Copper deactivator.|
Lubricants for arcing contacts.
Because the temperatures reached in an electric arc are sufficiently high to degrade any organic molecule, a lubricant’s tendency to “burn cleanly” is a definite advantage. Greases for arcing contacts should be formulated with fluids and thickeners that degrade with fewer by-products than traditional greases. Product recommendation – Nyogel 782D or for external contacts directly exposed to the weather, the water resistant version Nyogel 782DW.
New non-burning switch lubricant technology.
Greases that oxidise under arcing conditions pose a special problem for low load/low current applications. Traditionally, cleaner burning glycols (mentioned above – products such as 782D) are used to minimise carbon build-up. A new approach to eliminating problems associated with oxidation is to use Uniflor non-burning perfluoropolyether-based greases. Dispersed in a non-flammable, ozone-safe, fluorinated solvent, these greases leave a thin film of lubricant, ideal for low load/low current applications. Product recommendation – Uniflor 8511.
A note about damping greases.
Nye damping greases are widely used on the mechanical elements of many switch assemblies. They serve to reduce friction and wear, quiet detents, and give a smooth controlled ‘feel’ to switch operation. See our application page on Damping Grease for details.
The products mentioned above are the more popular from the range. If you do not find a product that fits your needs then please contact us as we have many more formulations on file for a large variety of switch types.