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Exchange thyristors size H8
3ADW000488R0101 DCS880 Service manual e a
Remove faulty thyristor
1. Remove the screws of all DC/AC - busbars preventing the stack to be prized open. Remove the branch
fuses, if the defective thyristors are covered by them.
Note:
It depends on the location of the defective thyristors, which DC/AC - busbars have to be disconnected.
2. Loosen the screws holding the backplate and make sure the backplate can move up.
3. Write down the direction and location of the defective thyristors to be removed and mark their gate leads.
4. Remove the gate leads if possible.
5. Loosen the mounting clamp at the top of the thyristor stack.
Attention:
While loosen the mounting clamp the indicating spring must be pulled out a little, otherwise the
spring will be damaged!
Do not remove the nuts totally, otherwise the treaded rods will fall down!