While top manufacturers like Nynas and Total produce both motor oil and transformer oil, these products are not interchangeable.
While it’s understandable that companies looking to cut costs will investigate alternative solutions, motor oil isn’t an acceptable alternative to transformer oils.
While both products are oils, they are designed with different purposes in mind – and to perform their role, they have distinctive properties that differ greatly. This makes them not only incompatible, but also potentially dangerous to interchange. Here, we look at their differences in detail.
Purpose
Motor oil is designed to lubricate and protect motor components. However, a transformer oil is specifically formulated to insulate and cool electrical transformers.
Additives
Motor oil includes additives like dispersants, detergents and anti-wear agents to help the lubricant work at high pressures and temperatures within an engine. Such additives are unsuitable for the thermal and electrical stresses inside a transformer and can degrade the electrical devices lifespan and overall performance.
Heat dissipation
Motor oil and transformer oil can dissipate heat, but they perform this process in different ways. For instance, transformer oil is engineered to circulate and effectively cool the core of the transformer and its windings, but motor oil isn’t optimised for this purpose. As a result, it may not supply sufficient cooling, causing overheating and unnecessary damage.
Dielectric strength and viscosity
Transformer oil requires highly specific dielectric strength (the capacity to resist electrical stress) and viscosity levels to function properly as an insulator. Motor oil does not offer these attributes to the appropriate degree and can compromise a transformer’s insulation, possibly resulting in electrical faults.
Damage potential
Deploying motor oil in a transformer is an error that can cause insulation failure, overheating, short circuits and ultimately result in the electrical component becoming damaged. The incorrect oil can also contaminate transformers and make them more difficult to clean and return to their original condition.
Consequently, the best advice is to keep motor oil in your vehicles and maintain your transformers by ordering a specially designed transformer oil from a dependable brand that meets the specifications of your original equipment manufacturer.
