M&I Materials is the name behind the highly successful specialist brand MIDEL®.

An independent company, M&I Materials has built a strong global business based on delivering technical excellence and high standards of customer service to niche markets worldwide. MIDEL® 7131 is a high performance transformer cooling and insulating fluid.

MIDEL® synthetic ester has a superior safety record of almost 30 years due to its high fire point and environmental safety. MIDEL® filled transformers are increasingly being specified for wind farms because the flawless fire safety record provides the reliability that is so crucial in this environment. It is also possible to design specific, optimised transformers that are smaller in size – this can become an important advantage. In a renewables environment, the environmental properties of MIDEL® 7131 are key.

The fluid has the capability to operate at high temperatures, under fluctuating loads and load surges. As all fluid filled transformers, they are more energy efficient than dry types. Because the fluid acts as a coolant as well as an insulator, there is less requirement for additional cooling. Synthetic ester is proven to work safely even at higher voltages – an important advantage in increasingly larger wind turbines.

In subsea and offshore applications, MIDEL® 7131 has been used for many years. Now MIDEL® filled transformers are also used in wind farms and in marine renewable technology such as the Pelamis from Ocean Power Delivery because of the fluid’s capability to operate well in humid environments. The added benefit in marine applications is, that the fluid will not harm the marine life should there be any leakage.