Wenzhou XiFa Electrical Power Equipment Co., Ltd is a transformer factory which located in Yueqing City, Zhejiang Province, China. The Factory main produce low voltage oil immersed transformer and 10 kv to 35 kv oil immersed transformers. Wenzhou XiFa electrical Power Equipment Co., Ltd built a strict quality control system from purchasing raw material to factory test. On each steps, inspectors would have necessary incoming product inspection and final test before delivery.




Q: What is an oil immersed transformer?
A: An oil immersed transformer is a common type of power distribution transformer, of which the core and winding are fully immersed in dedicated transformer oil.
1. Core features
The transformer oil acts as a coolant, insulator and arc extinguishing medium. It helps the device dissipate heat efficiently, insulate coils from air corrosion, and suppress arcs at high voltage contacts.
2. Basic structure
An oil immersed transformer consists of an iron core, coils, oil tank, insulating bushing, tap switch and other parts. It has the advantages of low loss, low noise and strong short circuit resistance because of fully sealing in transformer oil.
3. Main applications
An oil immersed transformer is widely used in urban and rural power grids, industrial and mining enterprises, hydro power plants, rail transit and petrochemical scenarios.
Q: What does ONAN and ONAF mean?
A: ONAN means Oil Natural Air Natural, more specifically:
it is Oil circulates naturally, Air cooling is natural, No fans, and No oil pumps. Most distribution transformers use ONAN cooling.
ONAF means Oil Natural Air Forced, more specifically:
it is Oil circulation is natural and Cooling fans are installed. The cooling system used for larger transformers requiring higher cooling capacity.