The grab differential limit switch is driven by holding and closing winches is used in auxiliary circuit for single lever grab control.
It is used for stopping the closing motor after closing or opening, regardless of the height of the grab, and starting the holding motor after closing, for transition to the hoisting action as well as for stopping the holding and closing motors at the highest and lowest grab positions.
The Switch contains six cam operated switch elements which are used as auxiliary circuit limit switches (see switching sequence diagram).
The dimension drawing shows that the switch has two shafts which must be driven by the holding and closing winches.
The contacts of the limit switches are 40 amps. rated at 500 v. a.c..
The limit switches are designed for heavy duty application. Housed in IP 54 degree of protection the housing is made of cast iron base and cover. The base and cover both have machined surface to protect against dirt and dust