PANASONIC-JC2AJ-DC48V
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General Application Guidelines
A relay may encounter a variety of
ambient conditions during actual use
resulting in unexpected failure
.
T
herefore,
testing over a practical range under actual
operating conditions is necessar
y
.
Application considerations should be
reviewed and determined for proper use
of the rela
y
.
SAFETY PRECAUTIONS
• Use that exceeds the specification
ranges such as the coil rating, contact
rating and switching life should be
absolutely avoided. Doing so may lead to
abnormal heating, smoke, and fire.
• Never touch live parts when power is
applied to the rela
y
.
D
oing so may cause
electrical shock. When installing,
maintaining, or troubleshooting a relay
(including connecting parts such as
terminals and sockets) be sure that the
power is turned off.
• When connecting terminals, please
follow the internal connection diagrams in
the catalog to ensure that connections are
done correctl
y
.
B
e warned that an
incorrect connection may lead to
unexpected operation error, abnormal
heating, and fire.
• If the possibility exists that faulty
adhesion or contact could endanger
assets or human life, take double safety
precautions and make sure that operation
is foolproof.
METHOD OF DETERMINING SPECIFICATIONS
In order to use the relays properl
y
,
t
he
characteristics of the selected relay
the environmental conditions, and at the
same time, the coil conditions, contact
conditions, and the ambient conditions for
the relay that is actually used must be
sufficiently known in advance. In the table
below, a summary has been made of the
points of consideration for relay selection.
It may be used as a reference for
investigation of items and points of
caution.
should be well known, and the conditions
of use of the relay should be investigated
to determine whether they are matched to
Specification item
Consideration points regarding selection
a) Rating
b) Pick-up
voltage (current)
c) Drop-out
voltage (current)
d) Maximum
continuous
impressed voltage (current)
e) Coil
resistance
1) Select
relay with consideration for power source ripple.
2) Give
sufficient consideration to ambient temperature and for the coil temperature rise.
3) When
used in conjunction with semiconductors, additional attention to the application
should be taken.
Coil
4) Be
careful of voltage drops when starting up.
f)
T
e
mperature
rise
1) It
is desirable to use a standard product with more than the required number of contacts.
2) It
is beneficial to have the relay life balanced with the life of the device it is used in.
3) Is
the contact material matched to the type of load?
It is necessary to take care particularly with low level usage.
4) The
rated life may become reduced when used at high temperatures.
Life should be verified in the actual atmosphere used.
a) Contact
arrangement
b) Contact
rating
c) Contact
material
d) Life
Contacts
e) Contact
resistance
5) Depending
on the circuit, the relay drive may synchronize with the AC load. As this will
cause a drastic shortening of life should be verified with the actual machine.
a) Operate
time
b) Release
time
c) Bounce
time
1) Working
life verification under actual conditions is required when switching frequency is
high because this will shorten life.
Operate time
d) Switching
frequency
a) Vibration
resistance
b) Shock
resistance
c) Ambient
temperature
d) Life
1) Give
consideration to performance under vibration and shock in the use location.
2) In
particular, when used in high temperature applications, relay with class B or class F coil
insulation may be required.
Mechanical
characteristics
1) Selection
can be made for connection method with plug-in type, printed circuit board type,
soldering, and screw fastening type.
2) For
use in an adverse atmosphere, sealed construction type should be selected.
3) When
used in adverse environments, use the sealed type.
4) Are
there any special conditions?
a) Breakdown
voltage
b) Mounting
method
c) Size
Other items
d) Protective
construction
BASICS ON REL
A
Y
H
ANDLING
•
T
o
m
aintain initial performance, care
should be taken to avoid dropping or
hitting the rela
y
.
one of the sealed types (sealed type, etc.)
temperature values listed in the catalog.
• Use the flux-resistant type or sealed type
if automatic soldering is to be used.
• Use alcohol based cleaning solvents
when cleaning is to be performed using a
sealed type rela
y
.
• Avoid ultrasonic cleaning of all types of
relays.
• Avoid bending terminals, because it may
cause malfunction.
• As a guide, use terminal mounting
pressure of 40 to 70N {4 to 7kgf} for relays
with plag-in terminals.
• For proper use, read the main text for
details.
should be considered.
• Proper usage requires that the rated
voltage be impressed on the coil.
• Be sure the coil impressed voltage does
not continuously exceed the maximum
allowable voltage.
• Under normal use, the relay is designed
so that the case will not detach.
T
o
maintain initial performance, the case
should not be removed. Relay
characteristics cannot be guaranteed if
the case is removed.
• The rated switching power and life are
given only as guides. The physical
phenomena at the contacts and contact
life greatly vary depending on the type of
load and the operating conditions.
Therefore, be sure to carefully check the
type of load and operating conditions
before use.
• Use of the relay in an atmosphere at
standard temperature and humidity with
minimal amounts of dust, SO
2
, H
2
S, or
organic gases is recommended.
Also note that use of silicon-based resins
near the relay may result in contact failure.
For installation in adverse environments,
• Do not exceed the usable ambient
16
General Application Guidelines
PROBLEM POINTS WITH REGARD TO USE
In the actual use of relays, various
tests are necessary under the possible
relay is a mass production item, and as a
matter of principle, it must be recognized
that the relay is to be used to the extent of
such variations without the need for
ambient conditions are encountered, and
because unforeseen events occur which
can not be thought of on the drawing
board, with regard to such conditions,
range of operation. For example,
consideration must always be given to
variation of performance when relay
characteristics are being reviewed. The
adjustment.
REL
A
Y
C
OIL
1. Power source for DC input
As a power source for the DC type rela
y
, a
battery or either a half wave or full wave
rectifier circuit with a smoothing capacitor
is used
.
T
he characteristics with regard to
the excitation voltage of the relay will
change depending upon the type of power
source, and because of this, in order to
display stable characteristics, the most
desirable method is perfect DC.
~
R
Relay
Smoothing capacitor
Ripple portion
In the case of ripple included in the DC
power source, particularly in the case of
half wave rectifier circuit with a smoothing
capacitor, if the capacity of the capacitor
is too small, due to the influence of the
ripple, humming develops and an
unsatisfactory condition is produced. It is
necessary to give consideration to the use
of a power source with less than a 5%
ripple, with the actual circuit to be used, it
is absolutely necessary to confirm the
characteristics. (Fig. 1)
DC portion
Emean.
Emax. Emin.
Emax.
–
Emin
Emean.
Emax. = Maximum value of ripple portion
Ripple percentage =
×
100%
Emin. = Minimum value of ripple portion
Emean.= Average value of ripple portion
Fig. 1
[1] It is desirable to have less than a 5%
ripple for the reed type relay (including NR
relay also).
[4] Shown on below, is a circuit driven by
the same power supply (batter
y
,
e
tc.) for
both the coil and contact.
[2] For the hinge type rela
y
, a
h
alf wave
rectifier cannot be used, alone unless you
use a smoothing capacitor
.
T
he ripple and
the characteristics must be evaluated for
proper usage.
[3] For the hinge type rela
y
,
t
here are
certain applications that may or maynot
use the full wave rectifier on it’s own.
Please check specifications with the
original manufacture.
Coil applied voltage and the drop in
voltage. Please verify that the actual
voltage is applied to the coil at the actual
load. Electrical life will be affected by the
drop in voltage in the coil when the load is
turned on.
2. Coil temperature rise
continuous current passage, it is rather
small. The various relays are essentially
the same in this respect.
• Pick-up voltage change due to coil
temperature rise (hot start)
Proper usage requires that the rated
voltage be impressed on the coil. Note,
however, that if a voltage greater than or
equal to the maximum continuous
impressed voltage is impressed on the
coil, the coil may burn or its layers short
due to the temperature rise. Furthermore,
do not exceed the usable ambient
temperature range listed in the catalog.
•
T
emperature rise due to pulse voltage
(Please refer to this when PWM control
will be used.)
When a pulse voltage with ON time of less
than 2 minutes is used, the coil
temperature rise bares no relationship to
the ON time. This varies with the ratio of
ON time to OFF time, and compared with
In DC relays, after continuous passage of
current in the coil, if the current is turned
OF
F
,
t
hen immediately turned ON again,
due to the temperature rise in the coil, the
pick-up voltage will become somewhat
higher. Also, it will be the same as using it
in a higher temperature atmosphere. The
resistance/temperature relationship for
copper wire is about 0.4% for 1
°
C, and
with this ratio the coil resistance
increases. That is, in order to cause
operation of the rela
y
,
t
he current
necessary becomes higher than the pick-
up current, accompanying the rise in the
resistance value.
Current passage time
%
T
e
mperature rise
value is 100%
For continuous passage
ON : OFF = 3 : 1
ON : OFF = 1 : 1
ON : OFF = 1 : 3
About 80%
About 50%
About 35%
1 : 1
Time
17
General Application Guidelines
3. Operate time
In the case of DC operation, to the extent
of large coil input, the operating time is
rapid, but if it is too rapid, the
“
A
”
contact
bounce time is extended.
Please be warned that load conditions (in
particular when inrush current is large or
load is close to the load rating) may cause
the working life to shorten and slight
welding.
4. Phase synchronization in AC load switching
If switching of the relay contacts is
synchronized with the phase of the AC
power, reduced electrical life, welded
contacts, or a locking phenomenon
Load
R
y
Load
voltage
Load
voltage
V
in.
(incomplete release) due to contact
material transfer may occur. Therefore,
check the relay while it is operating in the
actual system. However, if problems
V
in.
Fig. 2
develop, control the relay using an
appropriate phase. (Fig. 2)
5. Long term current carrying
In applications which involve lengthy duty
cycles, the preferred con
fi
guration would
be the use of the form B or N.C. contacts
for long term dut
y
.
I
n those instances
where the form A contact is held closed
for extensive time periods, coil heating will
increase contact
“
T
”
rise and may result in
shorter than optimum life. Alternatel
y
,
latching types may be considered for
these applications, using a storage
capacitor to
“
Reset
”
the relay on power-
down.
18
General Application Guidelines
CONTACT
The contacts are the most important
elements of relay construction. Contact
performance conspicuously in
fl
uenced by
contact material, and voltage and current
values applied to the contacts (in
particular, the voltage and current
waveforms at the time of application and
release), the type of load, frequency of
switching, ambient atmosphere, form of
contact, contact switching speed, and of
bounce.
1. Contact circuit voltage, current, and
load
[Voltage, AC and DC]
separately below, occurs in relation to the
contact wear. Ordinaril
y
,
t
he approximate
control capacity is mentioned in catalogs
or similar data sheets, but this alone is not
suf
fi
cient
.
W
ith special contact circuits, for
the individual case, the maker either
estimates from the past experience or
makes test on each occasion.
When there is inductance included in the
circuit, a rather high counter emf is
generated as a contact circuit voltage,
and since, to the extent of the value of that
voltage, the energy applied to the
contacts causes damage with
consequent wear of the contacts, and
transfer of the contacts, it is necessary to
exercise care with regard to control
capacit
y
.
I
n the case of DC, there is no
zero current point such as there is with
AC, and accordingl
y
,
o
nce a cathode arc
has been generated, because it is dif
fi
cult
to quench that arc, the extended time of
the arc is a major cause. In addition, due
to the direction of the current being
fi
xed,
the phenomenon of contact shift, as noted
[Current]
The current at both the closing and
opening time of the contact circuit exerts
important in
fl
uence. For example, when
the load is either a motor or a lamp, to the
extent of the inrush current at the time of
closing the circuit, wear of the contacts,
and the amount of contact transfer
increase, and contact welding and contact
transfer make contact separation
impossible.
Because of contact transfer, welding,
abnormal wear, increase in contact
resistance, and the various other
damages which bring about unsuitable
operation, the following items require full
investigation.
2. Characteristics of Common Contact Materials
Characteristics of contact materials are given below. Refer to them when selecting a rela
y
.
Electrical conductivity and thermal conductivity are the highest of all metals. Exhibits low contact resistance, is
inexpensive and widely used. A disadvantage is it easily develops a sul
fi
de
fi
lm in a sul
fi
de atmosphere. Care is
required at low voltage and low current levels.
Ag
(silver)
AgCdO
Exhibits the conductivity and low contact resistance of silver as well as excellent resistance to welding.
(silver-cadmium)
Like silver, it easily develops a sul
fi
de
fi
lm in a sul
fi
de atmosphere.
AgSnO
2
Exhibits superior welding resistance characteristics equal or better than AgCdO.
(silver-tin)
Like silver, it easily develops a sul
fi
de
fi
lm in a sul
fi
de atmosphere.
Contact
Material
Hardness and melting point are high, arc resistance is excellent, and it is highly resistant to material transfer.
However, high contact pressure is required. Furthermore, contact resistance is relatively high and resistance to
corrosion is poor. Also, there are constraints on processing and mounting to contact springs.
AgW
(silver-tungsten)
AgNi
(silver-nickel)
Equals the electrical conductivity of silver. Excellent arc resistance.
AgPd
At standard temperature, good corrosion resistance and good sul
fi
dation resistance. However, in dry circuits,
(silver-palladium)
organic gases adhere and it easily develops a polymer. Gold clad is used to prevent polymer buildup. Expensive.
PGS alloy
(platinum, gold, silver)
Excellent corrosion resistance. Mainly used for low current circuits. (Au : Ag : Pt = 69 : 25 : 6)
Combines perfect corrosion resistance and hardness. As plated contacts, used for relatively light loads. In an
organic gas atmosphere, care is required as polymers may develop. Therefore, it is used in hermetic seal relays
(reed relays, etc.) . Expensive.
Rh plating
(rhodium)
Au with its excellent corrosion resistance is pressure welded onto a base metal. Special characteristics are
uniform thickness and the nonexistence of pinholes. Greatly effective especially for low level loads under relatively
adverse atmospheres. Often dif
fi
cult to implement clad contacts in existing relays due to design and installation.
Au clad
(gold clad)
Surface
Finish
Au plating
(gold plating)
Similar effect to Au cladding. Depending on the plating process used, supervision is important as there is the
possibility of pinholes and cracks. Relatively easy to implement gold plating in existing relays.
Au
fl
ash plating
Purpose is to protect the contact base metal during storage of the switch or device with built-in switch. However,
(gold thin-
fi
lm plating)
a certain degree of contact stability can be obtained even when switching loads.
19
General Application Guidelines
3. Contact Protection
with the polarity shown in Fig. 1 (b) at the
• Material Transfer Phenomenon
Material transfer of contacts occurs when
one contact melts or boils and the contact
material transfers to the other contact. As
the number of switching operations
increases, uneven contact surfaces
develop such as those shown in Fig. 2.
After a while, the uneven contacts lock as
if they were welded together. This often
occurs in circuits where sparks are
produced at the moment the contacts
“
make
”
such as when the DC current is
large for DC inductive or capacitive loads
or when the inrush current is large
(several amperes or several tens of
amperes).
• Counter EMF
instant the inductive load is switched off.
The counter emf passes through the
power supply line and reaches both
contacts.
Generall
y
,
t
he critical dielectric
breakdown voltage at standard
When switching inductive loads with a DC
relay such as relay sequence circuits, DC
motors, DC clutches, and DC solenoids, it
is always important to absorb surges (e.g.
with a diode) to protect the contacts.
When these inductive loads are switched
off, a counter emf of several hundred to
several thousand volts develops which
can severely damage contacts and
greatly shorten life. If the current in these
loads is relatively small at around 1A or
less, the counter emf will cause the
ignition of a glow or arc discharge. The
discharge decomposes organic matter
contained in the air and causes black
deposits (oxides, carbides) to develop on
the contacts. This may result in contact
failure.
temperature and pressure in air is about
200 to 300 volts. Therefore, if the counter
emf exceeds this, discharge occurs at the
contacts to dissipate the energy (
1
/
2
Li
2
)
stored in the coil. For this reason, it is
desirable to absorb the counter emf so
that it is 200V or less.
A memory oscilloscope, digital memor
y
,
peak hold meter, etc., can be used to
measure the counter emf. However, since
the waveform is extremely steep,
considerable discrepancies may result
depending on the precision of the
equipment used. The table shows the
counter emf of various relays measured
on a high precision peak hold meter.
Actual measurement of counter emf on a
peak hold meter
The aim here is to use a contact
protection circuit or choose a contact
material that is suitable for the load.
Generall
y
, a
c
oncave formation appears
on the cathode and a convex formation
appears on the anode. For DC capacitive
loads (several amperes to several tens of
amperes), it is always necessary to
conduct actual con
fi
rmation tests.
ON OFF
E
0
Peak voltage
+
–
meter
–
Several hundred
to several
thousand volts
+
e
+
R
E
–
di
dt
Nominal Coil
e =
–
L
Voltage
12V DC
(a)
(b)
Relay
T
y
pe
CM relay
CM relay
Fig. 1 Example of counter emf and actual
measurement on a peak hold meter
Min. 1,600V
Approx. 85V
di
dt
Meterial transfer of contacts
In Fig
.
1
(
a), an emf (e =
–
L )
with a steep
waveform is generated across the coil
(Resistor inside type)
Fig. 2
• Contact Protection Circuit
Use of contact protective devices or
protection circuits can suppress the
counter emf to a low level. However, note
that incorrect use will result in an adverse
effect.
T
y
pical contact protection circuits
are given in the table below.
(G: Good, NG: No Good, C: Care)
Application
Circuit
Features/Others
Devices Selection
AC DC
If the load is a timer, leakage current
fl
ows
through the CR circuit causing faulty operation.
* If used with AC voltage, be sure the impedance
of the load is suf
fi
ciently smaller than that of the
CR circuit
Contact
As a guide in selecting r and c,
r: 0.5 to 1
Ω
per 1V contact voltage
c: 0.5 to 1µF per 1A contact current
C*
G
G
G
G
G
G
r
c
Values vary depending on the properties of the
load and variations in relay characteristics.
Capacitor c acts to suppress the discharge the
moment the contacts open. Resistor r acts to limit
the current when the power is turned on the next
time.
T
e
st to con
fi
rm. Use a capacitor with a
breakdown voltage of 200 to 300
V
.
U
se AC type
capacitors (non-polarized) for AC circuits.
Contact
If the load is a relay or solenoid, the release time
lengthens. Effective when connected to both
contacts if the power supply voltage is 24 or 48V
and the voltage across the load is 100 to 200
V
.
r
c
The diode connected in parallel causes the energy
stored in the coil to
fl
ow to the coil in the form of
current and dissipates it as joule heat at the resistance
least as large as the load current. In electronic circuits
component of the inductive load. This circuit further
delays the release time compared to the CR circuit.
(2 to 5 times the release time listed in the catalog)
Use a diode with a reverse breakdown voltage at least
10 times the circuit voltage and a forward current at
Contact
NG
NG
G
Diode
where the circuit voltages are not so high, a diode can
be used with a reverse breakdown voltage of about 2
to 3 times the power supply voltage.
Contact
Effective when the release time in the diode
circuit is too long.
Use a zener diode with a zener voltage about the
same as the power supply voltage.
Using the stable voltage characteristics of the varistor,
this circuit prevents excessively high voltages from being
applied across the contacts. This circuit also slightly
delays the release time. Effective when connected to
both contacts if the power supply voltage is 24 or 48V
and the voltage across the load is 100 to 200
V
.
Contact
Varistor
—
20
General Application Guidelines
•
Avoid using the protection circuits shown
in the
fi
gures on the right.
Contact
Contact
Although DC inductive loads are usually
more dif
fi
cult to switch than resistive
loads, use of the proper protection circuit
will raise the characteristics to that for
resistive loads.
Power
Power
supply
C
C
No good
No good
supply
Although extremely effective in arc suppression
Although extremely effective in arc suppression
as the contacts open, the contacts are
as the contacts open, the contacts are
susceptible to welding since energy is stored in
susceptible to welding since charging current
C when the contacts open and discharge
fl
ows to C when the contacts close.
current
fl
ows from C when the contacts close.
• Mounting the Protective Device
In the actual circuit, it is necessary to
locate the protective device (diode,
resistor, capacitor, varistor, etc.) in the
immediate vicinity of the load or contact
.
I
f
located too far awa
y
,
t
he effectiveness of
the protective device may diminish. As a
guide, the distance should be within
50cm.
• Abnormal Corrosion During High
Frequency Switching of DC Loads
(spark generation)
If, for example, a DC valve or clutch is
switched at a high frequenc
y
, a blue-green
corrosion may develop. This occurs from
the reaction with nitrogen in the air when
sparks (arc discharge) are generated
during switching. For relays with a case,
the case must be removed or air holes
drilled in the case. A similar phenomenon
occurs in the presence of ammonia-based
gas
.
T
herefore, care is required in circuits
where sparks are generated at a high
frequenc
y
.
Release time will slow down if, as shown
in the diagram, a diode is connected in
parallel to the coil in order to absorb relay
coil counter electromotive force. Please
test under actual load conditions because
electrical life will be affected depending on
the type of load.
4. Cautions on Use Related to Contacts
• Connection of load and contacts
Connect the load to one side of the power
supply as shown in Fig. 3 (a). Connect the
contacts to the other side. This prevents
high voltages from developing between
contacts. If contacts are connected to
both side of the power supply as shown in
Fig. 3 (b), there is a risk of shorting the
power supply when relatively close
contacts short.
R
y
E
E
(a)
(b)
R
y
R
y
R
y
(a) Good example
(b) Bad example
Fig. 3
• Avoid Circuits Where Shorts Occur Between Form A and B Contacts
1) The clearance between form A and B
contacts in compact control components
R
1
is small. The occurrence of shorts due to
arcing must be assumed.
2) Even if the three N.C., N.O., and COM
contacts are connected so that they short,
a circuit must never be designed to allow
R
1
Push-botton
switch
N.C.
N.O.
COM
M
R
Relay coil
R
R
2
the possibility of burning or generating an
R
2
overcurrent.
1) R
1
, R
2
: Contacts for R
2)
3) R
1
, R
2
: Contacts for R
: Double pole relay
R
: Double pole relay
R
3) A forward and reverse motor rotation
circuit using switching of form A and B
contacts must never be designed.
Fig. 4 Bad example of Form A and B use
• Shorts Between Different Electrodes
Although there is a tendency to select
miniature control components because of
the trend toward miniaturizing electrical
control units, care must be taken when
selecting the type of relay in circuits where
different voltages are applied between
electrodes in a multi-pole rela
y
,
e
specially
when switching two different power supply
circuits. This is not a problem that can be
determined from sequence circuit
diagrams. The construction of the control
component itself must be examined and
suf
fi
cient margin of safety must be
provided especially in creepage between
electrodes, space distance, presence of
barrier, etc.
21
General Application Guidelines
• Type of Load and Inrush Current
The type of load and its inrush current characteristics, together
with the switching frequenc
y
,
a
re important factors which cause
contact welding. Particularly for loads with inrush currents,
measure the steady state and inrush current
.
T
hen select a relay
which provides an ample margin of safet
y
.
T
he table on the right
shows the relationship between typical loads and their inrush
currents.
T
y
pe of load
Resistive load
Inrush current
Steady state current
Solenoid load
10 to 20 times the steady state current
5 to 10 times the steady state current
10 to 15 times the steady state current
Approx. 3 times the steady state current
1 to 3 times the steady state current
20 to 40 times the steady state current
5 to 15 times the steady state current
Motor load
Incandescent lamp load
Mercury lamp load
Sodium vapor lamp load
Capacitive load
Also, verify the actual polarity used since, depending on the rela
y
,
electrical life is affected by the polarity of COM and NO.
T
r
ansformer load
Load Inrush Current Wave and Time
(1) Incandescent Lamp Load
(2) Mercury Lamp Load
(3) Fluorescent Lamp Load
i/i
O
]
3 times
i/i
O
]
5 to 10 times
L
Contacts
i
i
i
o
i
o
C
i
i
o
(for high power factor type)
3 to
5 minutes
10 seconds
or less
Incandescent lamp
The discharge tube, transformer, choke coil,
capacitor, etc., are combined in common
discharge lamp circuits. Note that the inrush
current may be 20 to 40 times, especially if
the power supply impedance is low in the
high power factor type.
Approx. 1/3 second
Inrush current/rated current
=i/i
o
= 10 to 15 times
(4) Motor Load i/i
O
]
5 to 10 times
(5) Solenoid Load
(6) Electromagnetic Contact Load
(7) Capacitive Load
i/i
O
]
10 to 20 times
i/i
O
]
3 to 10 times
i/i
O
]
20 to 40 times
i
o
i
i
i
o
i
i
o
i
o
i
0.07
to 0.1 second
0.2 to 0.5 second
•
Conditions become more harsh if plugging or inching
is performed since state transitions are repeated.
•
When using a relay to control a DC motor and brake,
the on time surge current, normal current and off
time brake current differ depending on whether the
load to the motor is free or locked. In particular, with
non-polarized relays, when using from b contact of
from contact for the DC motor brake, mechanical life
might be affected by the brake current. Therefore,
please verify current at the actual load.
1 to 2 cycles
(1/60 to 1/30 seconds)
Note that since inductance is great,
the arc lasts longer when power is cut.
The contact may become easily worn.
1/2 to 2 cycles (1/120 to 1/30 seconds)
• When Using Long Wires
• Electrical life at high temperatures
Verify at the actual load since electrical
life may be affected by use at high
temperatures.
• If you plan to use in ways other than
those shown in the examples in this
catalog, please inquire beforehand to a
sales office, or verify the usage under
actual load conditions.
Equivalent circuit
If long wires (100 to 300m) are to be used
in a relay contact circuit, inrush current
may become a problem due to the stray
capacitance existing between wires. Add
a resistor (approx. 10 to 50
Ω
) in series
with the contacts.
+
Contacts
Stray capacitance
of wire
Added resistor
Wire
10 to 50
Ω
(100 to 300m)
• Phase Synchronization in Switching AC Loads
If switching of the relay contacts is
synchronized with the phase of the AC
power, reduced electrical life, welded
contacts, or a locking phenomenon
(incomplete release) due to contact
material transfer may occur. Therefore,
check the relay while it is operating in the
actual system. However, if problems
develop, control the relay using an
appropriate phase.
R
y
Load
voltage
Load
voltage
Load
V
in
V
in
22
General Application Guidelines
HANDLING CAUTIONS FOR TUBE
P
ACKAGING
Some types of relays are supplied in tube
packaging. If you remove any relays from
Slide in the plug.
the tube packaging, be sure to slide the
stop plug at one end to hold the remaining
relays
fi
rmly together so they would not
Stop plug
move in the tube. Failing to do this may
lead to the appearance and/or
performance being damaged.
AMBIENT ENVIRONMENT
1. Ambient Temperature and
4. Usage, Storage, and Transport
Conditions
1) During usage, storage, or
transportation, avoid locations subject to
direct sunlight and maintain normal
temperature, humidit
y
,
a
nd pressure
conditions.
The allowable speci
fi
cations for
environments suitable for usage, storage,
and transportation are given below.
•
T
e
mperature
:
T
he allowable temperature
range differs for each rela
y
,
s
o refer to the
relay
’
s individual speci
fi
cations.
In addition, when transporting or storing
relays while they are tube packaged,
there are cases when the temperature
may differ from the allowable range.
In this situation, be sure to consult the
individual speci
fi
cations.
2) Condensation
Condensation forms when there is a
sudden change in temperature under high
temperature, high humidity conditions.
Condensation will cause deterioration of
the relay insulation.
3) Freezing
Condensation or other moisture may
freeze on the relay when the
temperatures is lower than 0
°
C
32
°
F
.
This causes problems such as sticking of
movable parts or operational time lags.
4) Low temperature, low humidity
environments
The plastic becomes brittle if the relay is
exposed to a low temperature, low
humidity environment for long periods of
time.
Atmosphere
Be sure the ambient temperature at the
installation does not exceed the value
listed in the catalog. Furthermore,
environmentally sealed types (plastic
sealed type) should be considered for
applications in an atmosphere with dust,
sulfur gases (SO
2
, H
2
S), or organic gases.
2. Silicon Atmosphere
Silicon-based substances (silicon rubber,
silicon oil, silicon-based coating material,
silicon caulking compound, etc.) emit
volatile silicon gas. Note that when silicon
is used near rela
y
, switching the contacts
in the presence of its gas causes silicon to
adhere to the contacts and may result in
contact failure.
In this case, use a substitute that is not
silicon-based. Also, although absorption
by plastic does occur, it is insigni
fi
cant in
actual practice.
5.Vibration
,
I
mpact and Pressure when
Shipping
•
Humidity: 5 to 85% R.H.
•
Pressure: 86 to 106 kPa
The humidity range varies with the
temperature. Use within the range
indicated in the graph below.
When shipping, if strong vibration, impact
or heavy weight is applied to a device in
which a relay is installed, functional
damage may occur. Therefore, please
package in a wa
y
,
u
sing shock absorbing
material, etc., so that the allowable range
for vibration and impact is not exceeded.
3. Vibration and Shock
If a relay and magnetic switch are
mounted next to each other on a single
plate, the relay contacts may separate
momentarily from the shock produced
when the magnetic switch is operated and
result in faulty operation.
Humidity, %R.H.
85
Tolerance range
Countermeasures include mounting them
on separate plates, using a rubber sheet
to absorb the shock, and changing the
direction of the shock to a perpendicular
angle.
(Avoid freezing when
used at temperatures
lower than 0
°
C
32
°
F
)
(Avoid
condensation when
used at temperatures
higher than 0
°
C
32
°
F
)
5
–
40
–
40
0
+70
+158
+32
Temperature,
°
C
°
F
23
General Application Guidelines
ENVIRONMENTAL
L
Y
S
EALED TYPE REL
A
Y
S
Sealed type relays are available
.
T
hey are
effective when problems arise during PC
board mounting (e.g. automatic soldering
and cleaning). They also, of course,
feature excellent corrosion resistance.
Note the cautions below regarding the
features and use of environmentally
sealed type relays to avoid problems
when using them in applications.
2. Operating Environment of Sealed
Type Relays (generation of NOx)
When a plastic sealed type relay is used
in an atmosphere high in humidity to
switch a load which easily produces an
arc, the NOx created by the arc and the
water absorbed from outside the relay
combine to produce nitric acid. This
corrodes the internal metal parts and
adversely affects operation.
3. Cleaning
When cleaning a printed circuit board
after soldering, we recommend using
alcohol based cleaning
fl
uids. Please
avoid ultrasonic cleaning. The ultrasonic
energy from this type of cleaning may
cause coil line breakage and light sticking
of contacts.
1. Operating Environment
Plastic sealed type relays are especially
not suited for use in environments which
require airtight relays. Although there is
no problem if they are used at sea level,
avoid atmospheric pressures beyond
96±10kPa. Also avoid using them in an
atmosphere containing
fl
ammable or
explosive gases.
Avoid use at an ambient humidity of
85%RH or higher (at 20
°
C
68
°
F
). If use at
high humidity is unavoidable, consult us.
MOUNTING CONSIDERATIONS
1
.
T
op View and Bottom View
Relays used for PC boards, especially the
fl
at type relays, have their top or bottom
surface indicated in the terminal wiring
diagrams.
Furthermore, it is not desirable to switch
3. Adjacent Mounting
both a large load and a low level load with
a single rela
y
.
T
he scattered contact
material produced when switching the
large load adheres to the contacts when
switching the low level load and may
cause contact failure. Therefore, avoid
mounting the relay with its low level load
contacts located below the large load
contacts.
When many relays are mounted close
together, abnormally high temperatures
may result from the combined heat
generated. Mount relays with suf
fi
cient
spacing between them to prevent heat
buildup.
This also applies when a large number of
boards mounted with relays are installed
as in a card rack. Be sure the ambient
temperature of the relay does not exceed
the value listed in the catalog.
Relay with terminals
viewed from the bottom
(terminals cannot be
seen from the top)
2. Mounting Direction
Mounting direction is important for
optimum relay characteristics.
4. Plug-in Terminals
Vibration
As a guide, use a connect mounting
pressure of 40 to 70N {4 to 7 kgf} for
relays with plug-in terminals.
• Shock Resistance
It is ideal to mount the relay so that the
movement of the contacts and movable
parts is perpendicular to the direction of
vibration or shock. Especially note that
the vibration and shock resistance of
Form B contacts while the coil is not
excited is greatly affected by the mounting
direction of the rela
y
.
• Contact Reliability
Mounting the relay so the surfaces of its
contacts (
fi
xed contacts or movable
contacts) are vertical prevents dirt and
dust as well as scattered contact material
(produced due to large loads from which
arcs are generated) and powdered metal
from adhering to them.
Vibration
REGARDING CONNECTION OF LEAD WIRES
•
When making the connections,
Permissible current
(A)
Cross-section
(mm
2
)
0.2
0.3
0.5
0.75
1.25
2
depending upon the size of load, the wire
cross-section should be at least as large
as the values shown in the table.
2
3
5
7.5
12.5
15
20
30
2
3.5
24
General Application Guidelines
CAUTIONS FOR USE–Check List
Check Item
1. Is
the correct rated voltage applied?
2. Is
the applied coil voltage within the allowable continuous voltage limit?
3. Is
the ripple in the coil voltage within the allowable level?
4. For
voltage applied to a polarized coil, is polarity observed?
5. When
hot start is required, is the increase in coil resistance resulting from coil temperature rise taken into
account in setting coil voltage?
Coil Drive Input
6. Is
the coil voltage free from momentary drop caused by load current? (Pay special attention for self-
holding relays.)
7. Is
supply voltage
fl
uctuation taken into account when setting the rated coil voltage?
8. The
relay status may become unstable if the coil voltage (current) is gradually increased or decreased.
Was the relay tested in a real circuit or with a real load?
9. When
driving with transistors, did you consider voltage drops?
1. Is
the load rated within the contact ratings?
2. Does
the load exceed the contacts
’
minimum switching capacity?
3. Special
attention is required for contact welding when the load is a lamp, motor, solenoid, or
electromagnetic contractor. Was the relay tested with a real load?
4. A
DC load may cause contact lock-up due to large contact transfer. Was the relay tested with a real load?
5. For
an inductive load, is a surge absorber used across the contacts?
6. When
an inductive load causes heavy arc discharge across the relay contacts, the contacts may be
corroded by chemical reaction with nitrogen in the atmosphere. Was the relay tested with a real load?
Load
7. Platinum
contacts may generate brown powder due to a catalyzer effect or vibration energ
y
. Was the
relay tested with a real load?
(Relay contacts)
8. Is
the contact switching frequency below the speci
fi
cation?
9. When
there are more than two sets of contacts (2T) in a rela
y
,
m
etallic powder shed from one set of
contacts may cause a contact failure on the other set (particularly for light loads). Was the relay tested in
a real load?
10. A
delay capacitor used across relay contacts may cause contact welding
.
W
as the relay tested with a real
load?
11. A
high voltage may be induced at transformer load. Was the relay tested with a real load?
1. Does
circuit design take into account electrolytic corrosion of the coil?
2. Are
transistors and other circuit components protected from counter electromotive force that develops
across the relay coil?
3. Is
the circuit designed so the relay coil is left deenergized while the relay is inactive for long period of
time?
4. Is
the relay operated within the ratings approved by the relevant international standard (if compliance is
required)?
5. Is
the circuit protected from malfunction when the relay
’
s operation and/or release time varies
considerably?
Circuit Design
6. Is
the circuit protected from malfunctions that might result from relay contact bounce?
7. When
there are two or more sets of contacts (2T) in a rela
y
,
a
rc discharges from load switching may
cause short circuits across the two or more sets of contacts. Is the circuit designed to suppress such arc
discharges?
8. Item
7 above also requires special attention when loads are supplied from separate power sources.
9. Is
the circuit protected from malfunction when the relay is to be driven by transistors?
10. When
the SCR is used for on/off control, the relay activation tends to synchronize with the line frequenc
y
,
resulting in an extremely shortened life. Was the relay tested in a real circuit or with a real load?
11. Does
the PC board design take into account use of on-board relay?
25
General Application Guidelines
Check Item
1. Is
the ambient temperature in the allowable operating temperature range?
2. Is
relative humidity below 85 percent?
3. Is
the operating atmosphere free from organic and sul
fi
de gases?
4. Is
the operating atmosphere free from silicon gas? Depending on the load type, silicon gas may cause a
black substance to from on the contacts, leading to contact failure.
5. Is
the operating atmosphere free from excessive airborne dust?
Operating
Environment
6. Is
the relay protected from oil and water splashes?
7. Is
the relay protected from vibration and impact which may cause poor contact with the socket?
8. Is
ambient vibration and impact below the level allowable for the relay?
9. Is
the relay free from mechanical resonance after it is installed in position?
10. Is
insulation coating applied to the relay along with the PC board? Depending on the load type, a black
substance may form to cause contact failure.
1. Is
the relay protected from solder chips and
fl
ux when it is manually soldered?
2. Are
preparations for
fl
ux application and automatic soldering complete?
3. Is
the PC board cleaning process designed to minimize adverse affects to the relays?
4. Are
adequate separations provided between polarized or reed relays to prevent magnetic coupling?
5. Are
the relay terminals free from stress in the socket?
6. Polarized
relay’s characteristics may be affected by strong external magnetic
fi
eld. Are the relays
installed away from such
fi
elds?
7. If
very long leads (100 to 300 meters) are used to connect the load, the stray capacity existing across the
leads may cause a surge current. Was the relay tested with a real load?
Installation and
Connection
8. Unless
otherwise speci
fi
ed, all relay terminals should be soldered at 250
°
C
482
°
F
within 5 sec. or at
350
°
C
662
°
F
within 3 sec.
9. A
badly warped PC board can cause stress to the relay terminals which may lead to degraded relay
characteristics.
10. Glass
shot should not be used to clean the PC board of solder
fl
ux. This may cause relay malfunction
due to glass powder becoming lodged in the relay’s internal structure.
11. Relays
should always be used with their plastic shields installed, or degraded relay performance may
result.
12. Do
not cut away any relay terminal as the stress may cause degraded relay performance.
1. Is
the relay subject to freezing or condensation (especially when shipping)?
2. Is
the temperature in the allowable temperature range?
3. Is
the humidity in the allowable humidity range?
4. Is
the storing atmosphere free from organic and sul
fi
de gases?
5. Is
the storing atmosphere free from excessive airborne dust?
6. Is
the relay protected from oil and water splashes?
Storage and
T
r
ansport
7. Is
the relay subject to the application of heavy weight?
8. When
shipping does vibration and impact exceed the allowable range?
26
