WRM-4
5.3. Connecting subordinate circuits via a relay
Loads with a current consumption of more than 250 mA;
circuits or modules requiring to be galvanically isolated (e.g. track sections);
outputs of subordinate circuits
must be connected via a relay to the WRM-4 as a rule.
In addition you should connect a free-wheeling diode (e.g. 1N400x) in parallel to the relay in
order to avoid damages to the outputs of the WRM-4. Pay attention to connect the anode of
the free-wheeling diode (+) to the output of the WRM-4.
When supplying the WRM-4 with a.c. voltage, the relay possibly does not switch properly
("rattles") in operation. In this case you should mount an electrolytic capacitor (> 100 µF /
25 V) in parallel to the relay.
20 | Connecting subordinate circuits
tams elektronik
!
Attention:
When connecting
the
outputs
of
the
WRM-4
directly
to
the
outputs
of
subordinate
circuits (without
relay),
current
possibly
flows
back
from
the
subordinate
circuit
into the
WRM-4.
This
causes
damage
to
the
output,
possibly to the
complete
WRM-4.