The purpose of the oil pump is self-explanatory. This is a device to exert pressure on the oil to transport it from one place in the system to another.
In terms of control, there are two types of pumps: one type can adjust pressure in the system by changing capacity, others cannot.
There are two types of oil pumps:
- rotary pumps;
- gear pumps.
Rotary pumps push the oil by the vanes of the rotor, gear pump do it by gear wheels. Gear pumps can also be of two types: with external and internal gear contact. With the same capacity, the size of internal gear pumps is generally smaller than external ones.
To facilitate circulation of transformer oil, centrifugal pumps are used. They are driven by three phase short-circuited motors. Using pumps with packless seals allows to avoid contamination of oil. These devices can work with any medium which is not aggressive to the pump construction materials, contains no abrasive particles and has lubricating properties.