250kva dry type transformer

QIANLAI’s 250kVA three phase dry type transformer is a mainstream choice for medium and small power loads in industrial and civil construction scenarios due to its strong capacity adaptability, fire and explosion resistance, excellent insulation performance and flexible installation. It is suitable for the load requirements of single buildings, small and medium-sized production workshops, outdoor temporary power supply and other scenarios.

QIANLAI’s 250kVA Dry Type Transformer adopts advanced resin casting technology and premium materials, eliminating the fire and environmental risks associated with oil-immersed transformers. Designed for indoor and semi-outdoor applications, this unit is a cost-effective solution for scenarios requiring stable power conversion, low maintenance, and compliance with strict safety regulations.

How to adjust the tap changer of 250kva dry type transformer

In general, transformers have two types of voltage regulation with three taps and five taps, and each tap can adjust the voltage by 0.5kV. When installing a transformer, changing the position of the tap changer can alter the number of turns in the transformer windings, thereby changing the output voltage. Common transformers have a primary voltage of 10kV and a secondary voltage of 0.4kV. For a three-tap distribution transformer, Tap 1 is 10.5kV, Tap 2 is 10kV, and Tap 3 is 9.5kV, and it is usually set at Tap 2.

The operating steps for adjusting the tap changer are as follows:

First, cut off the power, disconnect the transformer load, use an insulating rod to open the high-voltage drop-out fuse, then take necessary safety measures, unscrew the protective cover of the transformer’s tap changer, and place the positioning pin in the neutral position.
When adjusting the tap, according to the level of the output voltage, adjust the tap changer to the corresponding position. When the voltage is too low, adjust to the low-voltage tap; when the voltage is too high, adjust to the high-voltage tap.
After adjusting the tap, use a DC bridge to measure the DC resistance of each phase winding and check whether the DC resistance between each winding is balanced. If the resistance difference between each phase is greater than 2%, re-adjustment is required. Otherwise, the moving and static contacts will heat up or even discharge due to poor contact, damaging the transformer.

250kva dry type transformer technical Specifications

Rated capacity	750kva
Rated voltage	6KV/10KV/33KV/35KV/40.5KV
model	SCB(10)-250/10/33/0.4KV or SCB(11)-750/10/33/0.4KV or SCB(12)-750/10/33/0.4KV or SCB(13)-750/10/33/0.4KV or SCB(14)-750/10/33/0.4KV or as per requirement
type	Dry type (cast resin)
No. of phase	3
Tapping range	±2X2.5%
Vector Group	Dyn11/Yyn0/as per requirement
Winding material	Copper/Aluminum
Core material	GRGO
Cooling method	AN/AF
standard	GB 1094/IEC 60076
Winding Temperature Rise	F insulation class(105K) H insulation class(125K)
No load loss	720±15% W or as per requirement
Load loss	2760±15% W or as per requirement
Short circuit impedance	4%
shell	Cold-Rolled Steel Sheet(IP20/IP23)/Stainless Steel