D4C-1202 Omron, D4C-1202 Datasheet - Page 24

• Manufacturer Part Number: D4C-1202
• Description: SMALL LIMIT SWITCH
• Manufacturer: Omron
• Series: D4Cr

Specifications of D4C-1202

• Rohs Compliant: YES
• Circuit: SPDT
• Switch Function: On-Mom
• Contact Rating @ Voltage: 5A @ 250VAC
• Actuator Type: Roller Plunger
• Mounting Type: Chassis Mount
• Termination Style: Cable Leads
• Operating Force: 1177gf
• Actuator Style: Roller Plunger
• Operating Force Max: 11.77N
• Contact Voltage Ac Max: 250V
• Contact Voltage Dc Max: 30V
• Contact Current Ac Max: 5A
• Contact Current Dc Max: 4A
• Switch Terminals: Cable
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: D4C1202

Contact Protective Circuit
Apply a contact protective circuit to increase the contact durability, prevent noise, and suppress the generation of carbide or nitric acid. Be sure to
apply the contact protective circuit correctly, otherwise an adverse effect may occur.
The following provides typical examples of contact protective circuits. If the Switch is used in an excessively humid location for switching a load
that easily generates arcs, such as an inductive load, the arcs may generate NOx, which will change into HNO
Consequently, the internal metal parts may corrode and the Switch may fail. Be sure to select the ideal contact preventive circuit from the
following. Also, load operating times may be delayed somewhat if a contact protective circuit (a surge killer) is used.
Typical Examples of Contact Protective Circuits
Do not apply contact protective circuits (surge killers) as shown below.
Using Switches for Micro Loads
Contact faults may occur if a Switch for a general-load is used to
switch a micro load circuit. Use switches in the ranges shown in the
diagram on the right. However, even when using micro load models
within the operating range shown here, if inrush current occurs when
the contact is opened or closed, it may increase contact wear and so
decrease durability. Therefore, insert a contact protection circuit
where necessary. The minimum applicable load is the N-level
reference value. This value indicates the malfunction reference level
for the reliability level of 60% ( 60). The equation, 60 = 0.5×10
operations indicates that the estimated malfunction rate is less than
1/2,000,000 operations with a reliability level of 60%.
CR circuit
Diode
method
Diode and
Zener
diode
method
Varistor
method
Power
supply
C
Load
Circuit example
This circuit effectively suppresses
arcs when the contacts are OFF.
The capacitor contacts are OFF.
Consequently, when the contacts
are ON again, short-circuited
current from the capacitance may
cause contact weld.
Power
supply
Power
supply
Power
supply
Power
supply
Power
supply
C
C
R
R
Inductive
load
Inductive
load
Inductive
load
Inductive
load
Inductive
load
*
Yes
No
No
Yes
Applicable
AC
current
Yes
Yes
Yes
Yes
Yes
DC
Power
supply
impedance must be lower than the
CR impedance.
The operating time will be greater if the load is
a relay or solenoid.
Connecting the CR circuit in parallel to the
load is effective when the power supply
voltage is 24 or 48 V and in parallel to the
contacts when the power supply voltage is
100 to 200 V.
Energy stored in the coil is changed into
current by the diode connected in parallel to
the load. Then the current flowing to the coil is
consumed and Joule heat is generated by the
resistance of the inductive load. The reset
time delay with this method is longer than that
in the CR method.
This method will be effective if the reset time
delay caused by the diode method is too long.
This method makes use of constant-voltage
characteristic of the varistor so that no high-
voltage is imposed on the contacts. This
method causes a reset time delay.
Connecting a varistor in parallel to the load is
effective when the supply voltage is 24 to 48 V
and in parallel to the contacts when the supply
voltage is 100 to 200 V.
*When AC is switched, the load
C
Load
This circuit effectively
suppresses arcs when the
contacts are OFF. When the
contacts are ON again, however,
charge current will flow to the
capacitor, which may result in
contact weld.
6
/
Feature
30
24
12
5
0
0.1
Unusable
range
5 mW
Precautions for All Switches
0.16 mA
Switching a DC inductive load is usually more
difficult than switching a resistive load. By using
an appropriate contact protective circuit,
however, switching a DC inductive load will be
as easy as switching a resistive load.
C: 1 to 0.5 F x switching current (A)
R: 0.5 to 1
The values may change according to the
characteristics of the load.
The capacitor suppresses the spark discharge of
current when the contacts are open. The resistor
limits the inrush current when the contacts are
closed again. Consider the roles of the capacitor
and resistor and determine ideal capacitance
and resistance values through testing.
Generally, use a capacitor that with a dielectric
strength of between 200 and 300 V. Use an AC
capacitor for an AC circuit i.e., a capacitor that
has no polarity.
If, however, the arc shutoff capacity between the
contacts is a problem at high DC voltages, it may
be more effective to connect a capacitor and
resistor across the contacts rather than the load.
Performing testing to determine the most
suitable method.
The diode must withstand a peak inverse voltage
10 times higher than the circuit voltage and a
forward current as high or higher than the load
current.
If a suitable Zener voltage is not used, the load
may fail to operate depending on the
environment. Use a Zener diode with a Zener
voltage that is about 1.2 times the power supply
voltage.
Select a varistor with a cut voltage Vc that
satisfies the following formula. For AC, the
voltage must me multiplied by the square root of
2.
Vc > Power supply voltage x 1.5
If Vc is set too high, effectiveness will be reduced
because high voltages will not be cut.
1 mA
1
Operating range for
micro-load models
3
x switching voltage (V)
10
if it reacts with moisture.
Element selection
800 mW
26 mA
100 mA 160 mA
100
Current (mA)
Operating
range for
standard
models
1,000
19