Many hydraulic systems share a familiar set of problems:

• Oil temperature alarms start around 45–50°C;

• Coolers are upgraded from air to water, from plate to shell-and-tube, yet performance still feels marginal;

• Operators joke that “this machine is always fighting against oil temperature.”

Looking deeper into the system, one common issue often appears:
the main pump operates for long periods in an inefficient part of its curve –
either running at very high speed most of the time, or holding high pressure at extremely low speed.
A significant portion of the motor’s input power ends up turning into heat inside the oil.

That’s why experienced engineers, when tackling energy and temperature issues, often start by asking:

“What type of pump are you using now? How were displacement, pressure and speed ranges selected?”

Switching to a pump designed for wide speed range and high-pressure duty – such as the FG internal gear pump –
is often a key step in addressing oil temperature problems:

• FG / FG21 are optimized for 200–3000 r/min wide-speed operation,
  reducing excessive leakage and ineffective churning at both low-speed holding and high-speed charging;

• With most models rated at 31.5 MPa and maximum up to 35 MPa,
  they operate efficiently in the high-pressure region, lowering the need to “overspin the pump” to reach target pressures;

• The internal gear design produces a more stable flow field,
  so more input energy is converted into useful work instead of wasted as shear heating and noise.

In retrofit projects, simply by:

• Adjusting pump displacement (for example, changing from an oversized unit to an appropriately selected FG1 25–40 mL/r or FG2 64.7–100 mL/r);

• Pairing it with rational servo or VFD speed control;

engineers can often reduce oil temperature by several degrees without upgrading the cooler.
Those few degrees may be exactly the difference between frequent alarms and safe operation.

For users seeking to cut temperature alarms and extend oil and seal life,
it often makes more sense to first verify whether the main pump is working efficiently within its pressure and speed window.
FG / FG21 are specifically optimized for such high-pressure, wide-speed applications.