Contact protection measures
Reed switches are basically designed for small contact ratings. To connect a load with higher power
consumption it is indispensable to use a contact protection relay (e.g. our series MSR01)
If you connect directly a load to a Reed contact the following recommendations should be con-
sidered.
None of the contact rating values printed on the switching unit must not to be exceeded, even mo-
mentarily. This is valid for each of the given values individually: voltage, current, power. The Reed
contact integrated in the switching unit is very sensible to electrical overload
Danger of overload is given by the following applications:
•
inductive load
•
capacitive load
•
lamp load
Inductive Load
Inductive loads consist e.g. of relay, contactors, solenoid valves, motors, electric engines, etc.
WARNING: Voltage spikes at shut down (up to 10 times of nominal voltage)
Protective measures: (examples)
(Flyback diode, e.g. type 1N4007)
Capacitive Load
Capacitive loads consist e.g. of long connection cables or capacitive consumers.
WARNING: High current spikes at switching on (this will exceed the nominal current)
Protective measures: (examples)
Limitation of current by a resistor
Lamp Load
Lamp loads consist e.g. by light bulbs, starting motors .
WARNING: High current spikes at switching on, because the glowing spiral has low resistance
at low temperature.
Protective measures: (examples)
Limitation of current by a resistor or
preheating of the glowing spiral.
DS09 Instruction manual 05/2018
page 11