CM On-Load Tap Changers with Multiple Coarse & Fine RegulationGeneral
CM on load tap changer (OLTC) applies to power and rectifier transformers with rated voltage 35kV, 63kV,110kV,150kV and 220kV, maximum rated through current 600A for three poles and 1500A for single pole, to change the taps under load for the purpose of voltage regulation. Three phase OLTCs are used at the neutral point of the Y connection, the single phase OLTC may be used for any connections. CM OLTC is a typical OLTC of combined structure, which consists of diverter switch
and tap selector.
CM on load tap changer is to be fastened to the transformer tank cover by its tap changer head which serves also for connecting to the motor driver CMA7 or SHM-III via the worm wheel reducer and bevel gear box for the purpose of tap changing.
When CM OLTC is used without a change-over selector,the maximum operating positions available will be 18, and will be up to 35 when it is used with a change-over selector. (special design is exclusive).
This operating instruction includes all the necessary information for the installation and operation of CM
OLTC.Type designationTechnical data of CM OLTC
Mechanical operation principle of the tap changer
The operation of tap change begins with the electric motor of the motor drive unit. The driving force is
transferred to the worm wheel reducer on the top cover of the tap change through driving shaft and belt pulley box. After the reducer, it is actuated to the energy acumulation mechanism and the shaft which passes through the diverter switch sown to the cylinder bottom.
There the cylinder bottom gear clutch is connected to the Geneva wheel mechanism of the tap selector. The rotation of Geneva wheel makes the contacting bridge to rotate an angle corresponding to one step, thus the connecting bridge will connected to the desired tap of the tap winding without load.
In the same time, the eccentric wheel of the energy accumulation mechanism makes the upper slide to move along the guide rail. The spring between the upper and lower slide is compressed to store energy, the cam wheel is locked by the clutch to hold the lower slide in its original position. When the upper slide moves to the release position, the side wall of the upper slide makes the corresponding jaw to move away from the locked cam wheel, thus releases the energy storage mechanism and operates the diverter switch. At this time, the lower slide moves to the new position, the clutch jaw again engages with the cam wheel, the mechanism is locked to prepare for the next tap change operation.
The motor drive mechanism automatically stops after performing one tap change.
Main product line: Tap changer and HV switchgear
Tap changer manufacturing with fullest vertical integration
Tap Changer Products Range On-Load Tap Changer:
* Conventional OLTC for transformer with voltage up to 765kV
*Vacuum OLTC for oil transformer with voltage up to 765kV
*Vacuum OLTC for dry transformer with voltage of 72.5kV
Off-Circuit Tap Changer
* Application for the transformer with voltage up to 765kV