Hubbell Euclid 4220 Specifications

Hubbell Industrial Controls, Inc.
EUCLID™ AC & DC POWER LIMIT SWITCHES
General Information
D-C Limit Switches are devices
that are used to interrupt the main
power circuit, setting up a dynamic
braking circuit that quickly stops
hook travel with a minimum of drift.
A-C Limit Switches are similar in
construction to D-C Limit Switches.
The difference is in operation. A-C
Limit Switches disconnect
power lines to the hoist motor
which then is stopped by a mag-
netic brake.
Positive trigger lock-out
Direct action contact open-
ing and closing
One-piece movable contacts
Exclusive arc transfer action
Sturdy housing
Safety chain on cover
Clearly marked leads
Rugged construction
Oversize ball bearings
Application
Euclid A-C and D-C Crane Power
Limit Switches provide dependable
protection against over-hoisting
problems such as damage to the
trolley frame and hoising mecha-
nism. In case of over-travel, these
Limit Switches disconnect the hoist
motor from the line, preventing
further hoist motion.
Operation
For dc operation the Power Limit
Switch is mounted on the trolley
floor of the crane. When the hook
block rises into the danger zone, it
lifts the suspended reset weight.
As the load of the reset weight is
removed from the operating lever,
the tripping weight (an integral part
of the operating lever) operates the
switch. Normally closed power
contacts are opened,
open dynamic braking contacts are
closed through a resistor.
SIZE 2, 3, 4, 5, 6, & 6A
two
motor armature and series brake
are disconnected from the supply
line. The armature, series field and
braking resistor are connected in
series. RESULT:
series holding brake and dynamic
breaking for a quick stop.
normally
Reversing the crane controller low-
ers the hook to return the Limit
The
Switch to the "run" position by
means of the suspended reset
weight.
For ac operation, when the Power
Setting of the Limit Switch is tripped, the shoe
brake is applied and the load is
stopped.
Hoisted when the Limit Switch is
tripped, but Lowering can be per-
formed as usual because the low-
ering circuit is unaltered.
SPECIFICATIONS
4220
November 2010
Repl. June 1994
The load cannot be