G - AA Electric

Relay coupler – overview
Contact types Protective circuits for the contacts Switching small and large capacities
Sold by AA Electric 1-800-237-8274 Lakeland, FL • Lawrenceville, GA • Greensboro, NC • East Rutherford, NJ www.A-Aelectric.com
Several contact types and combinations
are available ex stock:
1 NCC (EGR EG7, RS 30)
1 NOC (EGR RG7, DKR, RS 30)
1 NCC and
1 NOC (WRS)
2 NOCs (WRS)
3 NOCs (WRS)
1 change-over contact
(EGR/RST EG7, WRS,
DKR, PRS/PRZ MCZ R,
RS 30, RS 31)
2 change-over contacts
(WRS, RS 32, PRS/PRZ)
4/8/16 change-over contacts
(RSM)
Contact material
The relay modules are suitable for universal
use, with the choice of contact material
the crucial criterion. The contact is
used for safe transmission of control signals
and also for switching power contactors.
Gold-plated or gold-flashed AgNi contacts
are used for most applications. Hard
gold plated contacts with gold plating
exceeding 2 µm in thickness allow even
extremely small capacities (up to 40 µW)
to be switched. AgSnO2 or AgCdO contacts
are used for switching higher capacities
(RS 31).
The switching of inductive or capacitive
loads produces switching sparks which
can influence the electrical service life of
the relays.
The following protective circuits for the
contacts reduce contact wear:
Diode
–
Diode and Z-diode
–
RC combination
–
(~)
Varistor
+
Load
Advantage:
Disadvantage:
–
(~)
+
Load
+
(~)
Load
+
(~)
Load
R
C
VDR
U D
U ZD
U RC
U VDR
U S
1 2 t
Can be used for all capacities,
low overvoltage, minimum
space required, low price
Very large release delay
U S
1 2 t
Advantage: Low overvoltage (defined by
Z-diode), low release delay
Disadvantage: Cannot be used for large
capacities
U S
1 2 t
Advantage: Low overvoltage, low release
delay
Disadvantage: High current load on the contacts
when switching on;
more complicated and expensive
at greater capacities
Advantage:
Disadvantage:
U S Voltage progression
1 Closing
2 Opening
U S
1 2 t
Low release delay, low price
Cannot be used for all operating
voltages and capacities
For automation technology, the EGR EG7
relay coupler is ideal for switching
extremely small capacities (up to 40 µw)
under ohmic load. The signals are reliably
transmitted to the controllers. The switching
of large capacities for energy and
supply technology is achieved by the
RS31 relay coupler, with a guaranteed
switching capacity of 3.5 kVA under
ohmic load.
Switching times of the relay modules
Typical pick-up delay < 10 ms
Typical release delay < 12 ms
Contact service life under ohmic load
DC load-limit curve under ohmic load
Reduction factor F
Number of operations
Direct current (A)
Single contact
Switching capacity (kVA)
Direct voltage (V)
Power factor (cos )
Reduction factor under inductive load
cos ¥ < 1
No. of cycles eff. = No. of cycles at (cos ¥ = 1)
x red. factor F
Relay coupler
K
K.3