Honeywell Switches and Sensors Standards and Electrical rating, This symbol, Within the switch

LIMIT SWITCHES
Proper application of limit switches
The following are guidelines for the correct application of Limit Switches.								WRONG	WRONG
Never use the Limit Switch as a physical end stop. Mechanical damage or
incorrect operation may occur if this is done. Always ensure that the
mechanical actuator is protected from excessive mechanical shock. Never
release the actuator suddenly - gradual actuation and release will ensure that
stress on the mechanics of the switch is kept to a minimum. This has the
added benefit that the switch life will be improved. The diagrams illustrate how								RIGHT	FIXED STOP
to actuate your limit switch for optimum performance.									RIGHT
Standards and Electrical rating								For limit switches with pushrod actuators, the actuating force should be applied as
IEC/EN 60947-1explains the general rules relating to Low Voltage switchgear
								nearly as possible in line with the pushrod axis.
and controlgear. The purpose of this standard is to harmonize as much as
possible the product performance and test requirements for equipment where
the rated voltage does not exceed 1,000 Vac or 1,500 Vdc.
IEC 60947-5-1is part 5 of the general rules which relates to Control-circuit								WRONG		WRONG
devices and switching elements, where rated voltage does not exceed 1,000									over-riding
									cam
Vac or 600 Vdc. There are special requirements for control switches with
positive opening operation. These switches are marked on the outside with
this symbol:
								RIGHT		RIGHT
									over-riding
The Contact Element form defines the configuration and number of contacts									cam
within the switch.								Cam or dog arrangements should be such that the actuator is not suddently released
Form Za – both contact elements have the same polarity								to snap back freely.
Form Zb – the two contact elements are electrically separated.										free position
The Utilization Category defines the type of current carried – ac or dc – and										interference
the typical application where the switch is used.										end of
The contact rating Designation relates to the Utilization Categories and defines								WRONG	WRONG
										overtravel
the conventional thermal current Ith (a) rated operational current Ie (A) at										free position
rated operational voltages Ue and the VA rating.										operated
										position
										end of
Actuators										overtravel
								RIGHT	RIGHT
A range of actuators is available for limit switches. Illustrations of actuator								Operating mechanisms for limit switches shoud be so designed that, under any
types available from this catalogue are shown at the beginning of each
								operating or emergency conditions, the limit switch is not operated beyond its
product family. Other actuators may be available - for more information
								overtravel limit position. A limit switch should not be used as a mechanical stop.
please contact your local Honeywell office.
	Roller lever		Top roller	Adjustable	Top pin	Top pin
						plunger,
			lever	roller lever	plunger	boot seal
								WRONG
								non-over-riding
	Top roller		Top roller	Top roller	Top roller	Ball bearing
			plunger,	plunger,	plunger,
	plunger		boot seal	perpendicular	perpendicular,	plunger
					boot seal
								RIGHT
								over-riding
		Side	Side	Roller lever	Yoke lever	Rod lever	Wobble head
	pin plunger		roller plunger					For limit switches with lever actuators, the actuating force should be applied as
								nearly perpendicular to the lever as practical and perpendicular to the shaft axis
								about which the lever rotates.

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