OLTC go through mid position

[sisi29]

Hi every body,

firstly sorry if I do mistake I'm french and I don't speak a really well english.

So I'm in power station in United Kingdom, in the electrical commissioning team and we've got a problem.
We've got a OLTC (Technical parameter on the picture.
when we want to go from step 10 to step 8 the sequence is :
10 (Downer command) => 9C (not stop) => 9B (Downer command) => 9A (not stop) => 8

that the sequence we hope to

but when we want to go from step 8 to step 10 the sequence is :

8 (upper command) => 9A (Upper commande) => 9B (upper command) => 9C (Upper command) => 10

Can I and How can I do to configure the OLTC or the motor drive unit to go through the step 9A and the 9C without stopping? (same the first sequence)

thank you

 

[isquaredr]

At transfer tap positions a contact usually cam operated is made to hold in either the raise or lower contactor causing the tap changer to run on through the transfer tap. Find the contact on your schematic drawing and trace through the wiring checking the contact makes in either direction.

 

[sisi29]

Thank you very much for this quick answer,

but this contact is on the motor drive unit? or on the OLTC? or in an other part?

 

[inpran]

Sisi29,
Drive Unit. I had a similar problem an year back. It was just a case of a wire coming out lose in one of the contactors. Check the schematics in the Drive unit.

 

[ScottyUK]

If the Hyundai OLTC is similar to the ABB and Reinhausen designs then the switch is contained within the drive mechanism. If you are doing diagnostic tests wity the power on, or just tinkering with the microswitches , then be careful as it is possible to provoke the mechanism into motion. Losing fingers becomes a definite possibility.