Terasaki AT25 breaker gunged up

[SilverfoxUK]

Has anyone got experience with the now defunct Terasaki AT25 ACB.
The breaker is on a 415V LV system and rated at 2500A. Nice cosy environment, never been used on a fault in anger, not very many operations and about 25 years old.
The auto close mechanism is in good condition but caked in OEMs grease. The operations are very sluggish if at all. Even the flag takes an age to drop.
My thoughts are to flood the mechanism with WD40 which is a light paraffin to wash the grease away and restore the operations. Clearly WD40 does not appear in the maintenance manual.
Has any one had a similar experience and how did you sort it?

 

[Hoxton123]

I assume you are in the UK, if so, please see HSE website for a similar problem with the use of what i assume is WD40 or similar:

https://www.hse.gov.uk/safetybullet...tm_term=headline&utm_content=digest-29-sep-21

 

[SilverfoxUK]

Thanks for the link. I am in the UK so HG230 and the HSE are very relevant. clearly any degreasing would need to be followed by application of the manufacturers lubricants / grease.

 

[3DDave]

WD-40 in mechanisms often makes the current situation much better and then makes the situation much worse. Clock repairmen refer to WD-40 as a money maker when in the hands of the home tinkerer.

 

[waross]

I have had similar issues with other equipment. This problem is not specific to your breaker.
This is more an issue with the ageing of the grease.

clearly any degreasing would need to be followed by application of the manufacturers lubricants / grease.

Degrease with any effective method of your choice and then lube to manufacturer's specs.
I have had to disassemble mechanisms to scrape out hardened grease.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[oldfieldguy]

There comes a time in the life of a circuit breaker when it needs a complete tear-down and inspection, followed by reassembly using the proper lubricates.

WD-40 and its numerous imitations are NOT lubricants. Our substation crews called it "PM (preventive maintenance) in a can" because if a circuit breaker was operating slowly, a liberal dowsing with WD-40 would often free things up to pass today's testing. A month later? Not so good - failure or very slow operation as the WD-40's solvents that once freed up lubricants were now gone, leaving a mechanism in worse shape than before.

Local gunsmiths call it "The Gunsmith's Friend" for the same reason.

If you and your people are not qualified to do the refurbishment, employ a competent contractor and make sure they understand the scope of work.



old field guy