Dash pot time delay for starter overloads, was it real.

[ericmark]

It is some time ago, Ellesmere Port, around 1970, I seem to remember the in-rush delay for a starter was done using a dash pot with oil in them, google hunt failed to find them, seemed an excellent idea, as once started the overload would trip faster than the temperature type which replaced them. But am I dreaming or did they exist?

 

[Harry Bloomfield]

But am I dreaming or did they exist?

That was how it was done. A small brass disc, with a hole in, capped with a threaded, bakelite, black cover. Screwing the cover on and off, adjusted the calibrated delay time.

 

[bernardgreen]

Yes they did exist and still do. More resiliant than a bi-metalic sensor when the motors starting current might be 20 times the running current/

Google Search

 

[pete01]

Like this?

 

[Echo the husky]

They are good, except for the fact that when the oil gets old it can become more viscous changing the delay. I have an old book here somewhere that lists different oil types to use depending on the time delay required.