8
Ⅴ． ABOUT BUILT-IN MICRO SWITCH
1. Material of contact
a) Gold alloy contacts ( “for low electrical load” )
Stable contact performance is expected since oxidizing or
sulphidizing fi lm in not easily formed on gold alloy contacts.
However, they are not suitable for switching the load of high
capacity. If used for such applications, the contacts are rapidly
damaged due to sticking and blowout.
The max. rating of our Manostar switch having gold alloy
contact for micro lad is 100 mA, 30 V DC, resistive load. Use
the switches within the limits of the max. rating and the min,
rating.
b) Silver or silver alloy contacts ( “for general electrical load” )
In general, the contacts having silver as the main material,
which is easy to form surface oxide fi lm and, particularly, sulfi de
fi lm, contacts work fi ne in the early stage, but thereafter, on
low electrical load such an 10 mA, 24 V DC the fi rm cannot
break. It tends to occur contact failure by the fi rm.
When the current or voltage applied to the contact is high
enough to break the oxide/ sulfide film, is broken and the
contact is kept good contact.
Magnified drawing of contact
for low electrical load
(cross point contact)
Magnifi ed drowing of contact for
general load
(small rivet contact point)
2. Contact material and applicable mecanism for low voltage and low current circuit
The schematic diagram in the right
explains the proper range of load voltage
and current for which silver or gold alloy
contact is generally used when the contact
is used for opening or closing the low
voltage and low current circuit with a micro
switch. When referring to the diagram,
keep the following points in mind.
The working range for each contact may
actually be dependeding on the kind of
micro switch, contact pressure, working
condition, environmental condition, and
the kind of load, and so on. In general, the
contact should be selected based on the
required level of contact reliability.
ᵎ
ᵓ
ᵏᵓ
ᵑᵎ
ᵢᵡ
ᵎ
ᵓ
ᵏᵓ
ᵏᵐᵓ
ᵟᵡ
ᵏ
ᵓ
ᵏᵎ
ᵓᵎ ᵏᵎᵎ
ᵡᶓᶐᶐᶃᶌᶒ
ίᶋᵟὸ
ᵴᶍᶊᶒᵿᶅᶃίᵴὸ
ᵱᶇᶊᶔᶃᶐ
ᵥᶍᶊᶂᴾᵿᶊᶊᶍᶗ
ᶁᶐᶍᶑᶑᴾᶎᶍᶇᶌᶒ
３． Reset time
The reset time means the time needed for the differential pressure to decline to the reset pressure from the
activating pressure (i.e., the electrical contact is reset) when the differential pressure is sharply reduced
to zero. It is about three seconds at 20 Pa, and one second at more than 50 Pa for Manostar switches.
(This value is only for the instrument itself and does not include the effect of piping.) Therefore, a response
quicker than this value is not possible.
ᵱᶒᵿᶒᶇᶍᶌᵿᶐᶗ
ᶁᶍᶌᶒᵿᶁᶒ
ᵱᶒᵿᶒᶇᶍᶌᵿᶐᶗ
ᶁᶍᶌᶒᵿᶁᶒ
ᵫᶍᶔᵿᶀᶊᶃ
ᶁᶍᶌᶒᵿᶁᶒ
ᵱᶒᵿᶒᶇᶍᶌᵿᶐᶗ
ᶁᶍᶌᶒᵿᶁᶒ
ᵱᶒᵿᶒᶇᶍᶌᵿᶐᶗ
ᶁᶍᶌᶒᵿᶁᶒ
ᵫᶍᶔᵿᶀᶊᶃ
ᶁᶍᶌᶒᵿᶁᶒ
