Chinon Filtration Insulation/Transformer Oil Filtration MachineWhy They Are Not Interchangeable
| Aspect | Transformer Oil | Hydraulic Fluid |
| Primary Function | Insulation + cooling | Power transmission + lubrication |
| Additives | Antioxidants, anti-corona | Anti-wear (AW), extreme pressure (EP), anti-foam |
| Typical Viscosity | 10–15 cSt | 32–68 cSt |
| System Environment | High voltage | High pressure |
Key point: Transformer oil is made for electrical insulation, not for load-bearing hydraulic work.
Main Problems If You Use Transformer Oil in a Hydraulic System
- Viscosity too low→ weak pressure, more internal leakage
- No AW/EP additives→ pump and valve wear increases
- Seal incompatibility→ swelling, shrinking, or hardening
- Poor anti-foam performance→ pressure fluctuations and overheating
- Sludge risk→ clogging filters and valves over time
When It Can Be Used (Emergency Only)
| Situation | Feasible? | Note |
| Low-pressure systems (<50 bar) | ✓ | Only temporary |
| Older, low-speed pumps | ✓ | Monitor temperature and noise |
| Remote locations with no hydraulic oil | ✓ | Replace as soon as possible |
If You Must Use It Temporarily
- Reduce system load and pressure
- Check seal compatibility
- Monitor temperature, noise, and foam
- Flush the system thoroughly when switching back to hydraulic oil
Recommended Alternatives
- Standard hydraulic systems:ISO VG 32 / 46 / 68
- High-pressure systems:AW or HVLP hydraulic oils
- Fire-resistant applications:HFDU fluids
- Eco-friendly needs:HEES bio-hydraulic oils
Conclusion
Transformer cooling oil can be used as a temporary hydraulic fluid, but it is not suitable or safe for long-term use. The differences in viscosity, additives, seal compatibility, and pressure stability make proper hydraulic oil the only reliable choice for normal operation.