Off Load Tap-changer

Product Detail

Off Load Tap-Changer 
The main characteristics of this new series of tap changers are: Speed of installation; Safe and exact switch movement; Exact contact positioning after the switching maneuver; Compact dimensions; Possibility to adapt to the thickness of the transformer tank.

These units may be used with mineral oil or silicon liquid. They are fixed below the transformer cover by a support.
They allow adjustment or combinations according to the diagrams given in the following pages. There is no need for washers during assembly because the tap changer adjusts itself according to the thickness of the transformer tank.
Oil tightness is provided by O-rings. The catalogue illustrates normally used tap changers and standard accessories. Special tap changers may be designed to meet special requirements. Tap changing procedures are very quick and simple.
They must be performed with de-energized transformer in a no-load state. To switch, just lift the knob, rotating it until the desired number or mark coincides with the colored arrow on the washer. Release then the knob and make sure that it is fasten.

Model Explanation
 WST ? - ?/?-???
    W:  off-circuit
    S :  three-phase or D for single phase
    T :  linear type tap chager
    ?:  voltage regulation model
    ?:  rated current
    ?:  rated voltage
    ?:  number of tapping heads
    ?:  number of tapping position
Voltage Regulation Model
    I  :  terminal point
    II :   central point
    III :  neutral point
   IV :  Y-? conversion
   V :  series-parallel connection

Samples Technical Data

Specifications		WST 30	WST 63	WST 125	WST 250	WST 400	WST 500
Phase number		three-phases
Connection mode		Central point(?) Neutral Point(?) Terminal Point(?)
Rated through current(A)		30	63	125	250	400	500
Short-circuit capacity	Heat stableness current(KA/2s)	0.7	1.6	2.5	3.75	4	5
	Dynamic stableness current(KA)	1.8	4	6.25	9.375	10	12.5
Rated frequency		50~60
Insulation level(KV)	Rated Voltage	10KV		20KV		35KV
	Power-frequency withstand Voltage(50Hz/1min)	42KV		55KV		95KV
	Impulse(1.2/50µs)	75KV		125KV		250KV
Sealing Performance(KPa/24h)		60
Machine life(Thousands of times)		2