Toroidal transformer

According to foreign literature, Toroidal transformers can be divided into standard type, economic type and isolation type, and the characteristics of each type are: 

1. Standard power transformer products: 
Series capacity of 8 ~ 1500VA, small voltage adjustment rate, full load operation temperature rise of only 40℃, allow short-time overload operation, suitable for high demand applications. Grade B (130℃) polyester film insulation is used between the primary windings, requiring at least three layers of insulation tape, which can withstand the voltage test of 4000V and 1min. 

2. Economic power transformer products: 
Series capacity of 50 ~ 1500VA, on the basis of ensuring performance and striving to reduce the cost, suitable for continuous operation without overload applications, operating temperature rise of 60℃, insulation class A (105℃), when full load output voltage error is less than 3%. 

3. Isolation transformer products: 
Series capacity 50 ~ 1000VA, and can be divided into industrial and medical equipment with two series. Isolation transformer is focused on its insulation performance, primary and secondary with B-level insulation polyester film at least 4 layers wrapped, breakdown voltage is greater than 4000V, all primary must lead using double insulation wire. The maximum temperature rise of the transformer is lower than 45℃. 
In addition to the above requirements, isolation transformers for medical use should also meet the UL544 standard, that is, the primary and secondary windings should have thermal protection, and the distance between the windings and the earthed copper shield should be greater than 13mm.