Hubbell 4220 - Manual

Hubbell Industrial Controls, Inc.
INSTRUCTIONS
4220
INSTALLATION & MAINTENANCE INSTRUCTIONS
POWER LIMIT SWITCHES
EUCLID™ SIZE 2, 3, 4, 5, 6, & 6A
General
The EULCID™ Power Limit Switch is a device well
suited for crane hoist overtravel protection in repeti-
tively worked applications and under severe environ-
mental conditions. Maintenance requirements obvi-
ously will vary with service conditions. Even though
the device has been carefully designed to minimize
maintenance due to wear and adverse environmental
conditions, a periodic inspection and maintenance
program is mandatory in the interests of insuring
maximum protection.
The following sections treat various components of
the limit switch with suggested installation and main-
tenance practice.
Installation
EUCLID™ Power Limit Switches must always be
mounted with shaft in horizontal position with mount-
ing feet down. Under no circumstances attempt to
mount up side down. Provide adequate support under
each of the three mounting feet.
Install the split-sleeve reset weight guide around the
dead-ended cable, see Fig. 1. A bracket or striker
plate may be attached to the hook block, if necessary,
to lift the suspended weight when hoisting. Be sure
that the reset weight is positively engaged by the hook
block during hoisting under all conditions of hook
swing. Add additional guiding means to reset weight if
necessary to insure engagement by hook block.
Provide clearance or opening in Trolley platform so
that tripping weight cannot be prevented from drop-
ping slightly below level of mounting feet. This clear-
ance, or opening for the trip weight insures positive
switch action by preventing dirt buildup. Avoid the use
of sheave wheels or lever systems which can intro-
duce friction in reset weight cable assembly and re-
tard free action of tripping weight.
Right hand operation as shown, is furnished unless
otherwise specified. Field changing from right hand to
left hand operation is accomplished by turning trip arm
around and making proper electrical connections.
Terminal markings only are involved by this change.
Refer to wiring diagram for proper connections.
Maintenance
Periodic inspection for contact wear should be per-
formed. The size 3 and 6A contacts have a silver in-
lay. When the silver inlay is worn, both sets of con-
tacts should be renewed, see Fig. 5 for allowable
wear. Size 2, 4, 5 & 6 switches have solid copper
contacts as standard. Both sets of contacts should be
renewed when the contacts are worn, see Fig. 5 for
allowable wear. It is recommended that both the
movable and stationary contacts be renewed at the
same time.
Contact renewal steps are outlined in the following
procedure.