General
 

Type WSL Off-Circuit Tap Changers are used for adjusting the voltage of oil-immersed transformers. It is  
designed like a cage without oil compartment and can be vertically installed on the transformer tank cover
through top flange directly.

As per different operating modes, there're three types of tap changer: type motor drive unit tap changer; type
ground manual drive tap changer; type hand wheel on the head tap changer. The former can be operated by
motor unit while the latter two can be only operated manually.

As per different internal structures,and regulating mode there are six types of tap changer: Type Linear off-
circuit tap changer for neutral application; Type Single-bridging off-circuit tap changer; Type Star-delta off-
circuit tap changer;

Type Double-bridging off-circuit tap changer; Type Reversing off-circuit tap changer; Type Serial-parallel off-
circuit tap changer

As per different sizes, there are two types of tap changer: type A and type B.

There are two type of flange mounting: tank cover type and bell type.

The ground motor drive tap changer is equipped with a motor drive unit. See fig.15 for connection and "CMA9
Motor Drive Unit Instructions" specifies the operating instructions for the motor drive unit.

This instruction contains all the information for installing and operating of the three types off circuit tap changer.

Designation of tap changer model 

Application range

The max. current of the tap changer is 600A, the highest voltages for equipment are 12kV and 40.5kV, It is
divided to linear regulation at neutral point and single-bridging regulation at middle of winding, the max.
operation position is up to 13 for single-bridging regulation and 14 for linear regulation.

Warning: The tap changer can be operated for changing the tap of a winding only when the 
transformer is de-energized.

Structure

This type off-circuit tap changer consists of gearing mechanism and body, gearing mechanism is on the head
of the tap changer, which can be mounted onto top cover of transformer tank; while the body,structured as cage
form and without oil compartment, can be mounted into transformer tank.

Characteristics:

(1) All gearing components are located inside the compartment above the flange, isolating from transformer.
Gearing components features as compact structure, small size, good appearance and convenient for maintenance.

Note: The gearing mechanism compartment on the tap changer head should be fully filled with

transformer oil before putting into operation.

(2) WSLV and WSLIV series off-circuit tap changer can be affiliated with HMWK-1 controller that can indicate the tap
     position and operate the tap changer manually by push button at control room.

(3) Clip contact structure, good heat dissipation, reliable contact and strong ability to withstand short-circuit current.

(4) Reliable operation is secured further by electrical and mechanical limit protection.

(5) The control circuit of tap changer controller is interlocked with that of transformer, the power supply of controller is
     disconnected when transformer is energized, and therefore, ensuring tap changer could not operate in on-load condition.

(6) It is only suitable for standard tank mounting.

Drying

1.Open the top cover of tap changer

2. Drying procedure: under standard atmospheric pressure, heat up the tap changer at a temperature increasing rate of
   10C per hour until 110C, and then keep drying with circulating hot air for 24 hours.

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