Differences

This shows you the differences between two versions of the page.

--- electrical:relay [2017/07/08 23:24]
frater_secessus created
+++ electrical:relay [2020/10/11 19:48] (current)
@@ Line 1: / Line 1: @@
 ====== Relays ======
+Electrical relays are devices used to **turn relatively heavy loads on/off**.  They are //triggered by small amounts of power// from an external source (usually a switch operated by the user) but //can pass larger amounts of power// to the load.  This reduces the cost and physical requirements of the switch and can help automate some processes.
+A typical setup looks like this:  switch (and house power) --> relay --> load
+The most common relay campers are exposed to is the solenoid for [[electrical:12v:alternator|charging house batteries from the coach's alternator]].  When the vehicle is turned on power activates the solenoid and connects the house and vehicle electrical systems.
+Relays are also useful for powering loads from [[electrical:12v:lvd|LVD]] or [[electrical:solar:charge_controller|Charge Controller]] LOAD outputs.  This allows powering larger loads than the controller is rated for.
-Electrical relays are devices used to **turn relatively heavy loads on/off**.  They are triggered by small amounts of power from an external source (usually a switch operated by the user) but can pass larger amounts of power to the load.
+Common uses:
+  * battery isolation when [[electrical:12v:alternator|alternator charging]]
+  * [[electrical:12v:lvd|low voltage disconnect (LVD)]]
-switch (and house power) --> relay --> load
+===== normally open vs normally closed =====
+Relays come in two basic types:
-The most common relay is the solenoid that campers use to [[electrical:12v:alternator|charge house batteries from the coach's alternator]].  They are also useful for powering loads from [[electrical:12v:lvd|LVD]] or [[electrical:solar:charge_controller|Charge Controller]] LOAD outputs.
+  - **Normally Open (NO)** - the output circuit is open/incomplete when the relay is resting.  No power flows.  The controlled device is **off** until the relay is triggered.  //This is usually the default.//
+  - **Normally Closed (NC)** - the output circuit is closed/complete when the relay is resting.  Power flows.  The controlled device is **on** until the relay is triggered.
+===== latching relays =====
+Normally it takes power from the trigger source to operate the relay.  A latching relay, however, moves from position to position and locks there even when power is removed.

RV and vandwellers wiki

User Tools

Site Tools

Differences

Page Tools