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GRAB DIFFERENTIAL LIMIT SWITCH
‘Suni’ Make 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 cams operated switch
elements which are used as auxiliary circuit limit switches. 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 415 Volts A.C.,
50 C/S Continuous. 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.
‘Suni’ Make Grab differential Limit Switch is driven by
holding and closing winches is used in auxiliary circuits 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 & closing motors at the
hoisting & lowest grab position.
Construction:
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 contracts of limit switches are 40 Amps rated at 500 V. A. C.
Mode of operation:
The switches N5, N6 are limit switches for the highest and lowest grab positions.
The 'Grab closed' and 'Grab open' limit positions are monitored by the switches
N1 & N4, whereas N2 & N3 initiate the switching operations for single lever grab
control.
Installation:
The switch is best arranged to one side of the winch space between the drums where
it should be easily accessible. It can be mounted either in a horizontal or a vertical
position. However, the former is preferred since the switching equipment and gearing
can be reached more easily when the cover has been removed. Auxiliary shafts connected
to the winch of the grab hoisting gear are best used for driving the switch. The
closing winch is connected to shaft 1 at the differential gear end and the holding
which is joined to shaft 2 at the same or opposite end of the switch.
Accessories:
A special wrench is needed to release the locking nut when adjusting the cam discs.
This wrench is included with the switch.
Specification Details
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