Panasonic is part of a large worldwide groupselling relays and associated switching products under different brand names in different territories.The conditions of use in some territories may differ from those customary in Europe. In particular there are often major differences in regard to national and international specifications, such as UL, CSA, VDE, SEV, EVE, SEMKO, etc. Thus, when considering contact loads as stated in this catalogue (e.g. 10 A, 30 VDC for the SP relay) its hould be understood that these values are not necessarily an absolute maximum but tested ratings. Mostly the stated value has been tested for a certain life expectancy as stated by the manufacturer or the respective test house. Thus, under different conditions, the stated “maximum” may, in practice, be safely exceeded.
The
table the right shows the relationship
Type load Inrush current
Resistive load Steady state current
Solenoid load tim the steady state current
M otor load tim the steady state current
Incandescent lam load tim the steady state current
M ercury lam load Approx.
Also, verify the actual polarity used since,
depending the relay, electrical life is
affected the polarity COM and NO.
• life s
Verify the actual load since electrical
life may affected use high
temperatures. tim es
• Conditions become more harsh plugging inching i
performed since state transitions are repeated. The contact
may beome easily worn.
L
- -
(for high power factor type)
ft
ft
Contacts
C
(4) otor Load i/io approx. 50Q) series
with the contacts.
L e
(1) Incandescent Lam Load (2) ercury Lam Load
i/io approx. Note that the inrush
current may times, especially if
the power supply impedance low the
high power factor type.
• hen using relay motor and Note that inductance great the arc
the time inrush current’ steady state current and Nsts longer when power The contact
time brake current differ depending whether the
load the motor free locked., are combined common
discharge lamp circuits.10 tim es
(6) lectrom agnetic ontact Load
i/iOapprox.
ds_x61_en_relay_technical_information_091112D 15
.General Application Guidelines
• t
The type load and its inrush current
characteristics, together with the
switching frequency, are important
factors which cause contact welding. Add
a resistor (approx. A
Inrush current/rated current:
i/io] times
The discharge tube, transformer, choke coil,
capacitor, etc.
lasts longer when power cut. Therefore,
please verify current the actual load. Then select relay which
provides ample margin safety.
Particularly for loads with inrush currents,
measure the steady state and inrush
current. tim the steady state current
Sodium vapor lam load tim the steady state current
Capacitive load tim the steady state current
Transform load tim the steady state current
between typical loads and their inrush
currents. tim (5) Solenoid Load
i/io approx. particular, with
non-polarized relays, when using from contact of
from contact for the motor brake, mechanical life
might affected the brake current. tim es
(3) Fluorescent Lam Load
i/io approx. tim es
3 5
minutes
' 1
' io
. tim es
(7) Capacitive Load
i/io approx.
(1/60 1/30 seconds)
1/2 cycles (1/120 1/30 seconi
• s
If long wires (100 300m) are used
in relay contact circuit, inrush current
may become problem due the stray
capacitance existing between wires
