DB Breakers

[farmaped]

Can someone explain the difference between old W DB circuit breakers "Single Position" and "Three Position".
I'm not sure, but I think the "Single Pos." can only open under load, they must be closed no-load due to no spring-latch mechanism for closing. Then again, I may be way off.
Can the average Joe determine the type from the exposed operating handle?
Thanks

 

[zog]

It refers to the racking positions, the 1 position does not have a "test position". You can see the difference by an extended front escusion on the 3 position whereas the 1 position has flat plate across front behind handle.

 

[farmaped]

Thank you, as usual my thought was wrong.
Are you familiar with the type of closing mechanism that doesn't spring close, as described above?

 

[zog]

Sure, we remanufacture those all the time, I have a dozen or so in the shop and about 400 of those in storage.

 

[farmaped]

Do you have many with burnt contacts, from perhaps being inadvertantly closed onto a load? To me, this style of breaker would/should be clearly identified.

 

[zog]

Do you have many with burnt contacts, from perhaps being inadvertantly closed onto a load? To me, this style of breaker would/should be clearly identified.

We replce conacts on all breakers that get remanufactured, closing into full load wont do any damage, the breaker is designed to handle that, it is the fault current inturuption that damages the contacts. Thats why manufactures recommend the breaker is reconditioned or remanufactured after only 1 or 2 fault interuptions. (Depending in the breaker type)

 

[farmaped]

What would happen if this style is closed onto a fault? Does it have trip free characteristics?
Thanks

 

[zog]

What would happen if this style is closed onto a fault? Does it have trip free characteristics?
Thanks

Yes it has trip free but I would hate to be the one closing one into a fault.