Relay Purpose ... ?
I frequently read "check your relay" in threads here on the rvnet. I've read several Google explainations and still don't understand their function. In very simple layman terms ...... could someone ex...
Forum Discussion
A relay is used for one of two purposes.
First: This is most common in automotive use... A remote switch sends a small current to the relay,, The relay can then switch a much higher current.
For example. 5 amps to the coil 100 amps to the starter (The Starter Solenoid is in fact a relay).
This also works when you are using a low current (power) transistor to switch a larger current (the blower motor on your furnace)
It can also be used for "Automatic transfer" two cases of this, One is the Auto-Transfer-Switch that selects either Shore Power or Generator power, the actual switch is a bank of relays.
or in a Magnnetek 6300 there is an isloator relay that isolates the battery and charger circuit from the converter circuit, a very bad design in my opinion.
But it is basically either a remote switch or a way to make a small current control a much larger current.
The most common failure mode is dirty/pitted contacts, followed by welded contacts and finally coil failure.
First: This is most common in automotive use... A remote switch sends a small current to the relay,, The relay can then switch a much higher current.
For example. 5 amps to the coil 100 amps to the starter (The Starter Solenoid is in fact a relay).
This also works when you are using a low current (power) transistor to switch a larger current (the blower motor on your furnace)
It can also be used for "Automatic transfer" two cases of this, One is the Auto-Transfer-Switch that selects either Shore Power or Generator power, the actual switch is a bank of relays.
or in a Magnnetek 6300 there is an isloator relay that isolates the battery and charger circuit from the converter circuit, a very bad design in my opinion.
But it is basically either a remote switch or a way to make a small current control a much larger current.
The most common failure mode is dirty/pitted contacts, followed by welded contacts and finally coil failure.
