Lubrication systems
Reading a lubrication pump specification: what the numbers on the leaflet mean
NLGI range, pressure, temperature, reservoir, outlets, output and ingress rating. What to check before a pump goes on a machine.
Typical figures
These are typical figures for a compact electric pump used on mobile and industrial machines. They show what to expect from the specification table of any pump, not a recommendation of a model.
What to compare
| Parameter | Typical value | What to check against |
|---|---|---|
| Lubricants | Grease up to NLGI 2, or oil of about 40 to 1,500 mm²/s operating viscosity | The grease you actually use, at the coldest start-up temperature. Stiffer grease than the pump is rated for will not feed |
| Maximum pressure | About 350 bar | Line length, number of metering devices and grease stiffness. Pressure drops along long lines |
| Operating temperature | About −40 to +70 °C on DC supply, narrower on AC | Site climate. Cold sites need a lower-temperature grease as well, not only a pump rated for it |
| Reservoir | 2 to 15 litres | Consumption per day. A reservoir that lasts a full inspection interval avoids emergency refills |
| Pump elements | Up to three | One element per independent circuit. Separate circuits isolate a blocked line |
| Output per outlet | About 0.7 to 4 cm³/min | Total demand of all points per cycle |
| Ingress protection | IP6K9K (dust-tight, high-pressure hot-water jets) | Washdown, dust and mud. Dusty plants need the top dust rating |
| Supply | 12/24 V DC or 115/230 V AC | The machine's electrical system |
Details that save trouble
- A stirring paddle in the reservoir keeps the grease free of air bubbles, which would otherwise cause a pump to run but not deliver.
- Visual level monitoring plus a level signal output lets operators and controllers see a low tank.
- Signal inputs and outputs (cycle switch, error, extra lubrication, machine contact) are how the pump talks to the machine. Check that the connector variant matches your wiring.
- Electrical connector style differs between mobile (bayonet) and industrial (square plug) variants.
Takeaway. Start from your grease and your coldest morning, not the pump's maximum numbers.
Put it to work in the tool