operation of oil switch

[chabby]

hello . I once knew how an oil pressure differential switch work..could someone tell me again how it works both mechanically and electrically ..the aid of an electrical hook up is appreciated

[frank]

Hi Chabby

The oil pressure switch is a safety device to protect the compressor.

At switch on it will allow the compressor to run for a set time, say, 60secs, 90secs or 120secs, during which time it is looking for a differential in the oil pressure.
When a voltage is applied to the switch, a small heater is energised that will run for the set time (above) before breaking the compressor control circuit.
If a dp is available on the system (i.e. good oil pressure) then the bellows pressure operates another relay which bypasses the heater contacts and allows the compressor to run.

[frank]

I tried to edit my previous post but it wouldn't reload.

have a look here http://www.danfoss.com/Products/ProductFinder/ProductFinder.htm?segment=RA&category=http%3a%2f%2fwww.ra.danfoss.com%2fra%2fProducts%2fProductCatalogue.asp%3fNavigation%3dHideO nAllPages%26Footer%3dHideonallpages%26Division%3dRC%26HL%3d1%26TopViewItem%3d92%26AppID%3d%7bc2a95da c-5e01-47df-92cd-5972d837cf1a%7d%26dyn_lang%3d

[chabby]

thanks very much Frank....the info helped..