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Tap Changer Manual Raise / Lower

Tap Changer Manual Raise / Lower

Tap Changer Manual Raise / Lower

(OP)
The existing engineering on our tap changer unit has a 5.1kohm, 10W resistor placed on both the manual raise and on the manual lower points.

The only reason I could see doing this would be for voltage loss but theirs nothing that is telling me there would be any.

Any ideas.

RE: Tap Changer Manual Raise / Lower

What is the input voltage and what is the voltage rating of the Raise and Lower Auxiliary relays? How is the resistor connected?

If the voltage for the on the source side of the manual push buttons is higher than the rating of the Auxiliary relays the resistor could to provide a voltage drop and hence the rated voltage across the Auxiliary Relay. The higher wattage rating of the resistor makes me think this could be the designed use.

Compare this to where the Raise/Lower circuitry receives it voltage from the automated tapchanger control. Does it use the same supply?

This is not an idea situation but liveable if the manual points are only used rarely.  

RE: Tap Changer Manual Raise / Lower

If the resistor is at the contactor it may be designed to increase the burden on the control circuit to ensure it switches off cleanly and doesn't hold in due to cable capacitance.
  

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If we learn from our mistakes I'm getting a great education!
 

RE: Tap Changer Manual Raise / Lower

dynamic braking?

RE: Tap Changer Manual Raise / Lower

How about a schematic for this controller? That would at least focus the speculation.
  

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If we learn from our mistakes I'm getting a great education!
 

RE: Tap Changer Manual Raise / Lower

(OP)
I filed been in the field the last few days trying to figure why this was in place and it actually was for voltage loss but for equipment that was made 30years ago and they serve no purpose now so they have been removed.

Thanks for the comments.

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