electrical issues relat solenoid

[Gregory OConnor]

The forum/shop talk use of the term "relay" and "solenoid" often
create confusion with members that want to follow a thread and do
repairs at home.

Both a relay and solenoid are electrical switches that act like a
toggle switch. A toggle switch is moved by hand but a relay and
solenoid switch is moved by electrical current. The current that
throws the switch "Control current" has nothing to do with the
current that the switch passes.

Example of a '12vdc control / 120vac contact Solenoid'
A dash mounted AC switch is a hand thrown toggle switch that passes
12 volts to a '12vDC actuated - 120vAC solonoid switch'. the 12
volts is the "control current" that pulls a plunger in the solenoid
to make contact and pass 110 voltsAC for the airconditioner/heater.
*** vdc = volts of direct current, like from a car battery
*** vac = volts of alternating current, like from a wall socket

If you leave the dash ac toggle switches on, they are always
energizing the solenoid and the 12vdc current that holds the
solenoid switch on is amperage lost. I believe this is one of the
phantom loads.

Technicaly a solenoid is a relay. But common referance refer to a
relay as slang for a 'Bosch relay switch'. The term Solenoids refer
to larger round metal plunger actuated relay switch.

Example of a bosh relay
many members install bosh relays for head light because the dash
toggle headlight switch cotacts and wires are not large enough and
develop a resistance which will not allow the running lights to glow
as bright as they should. with this relay add-on the existing dash
headlight toggleswitch is used to send control voltage to one Bosch
relay for each light. the dash switch no longer turns on the light,
it moves the swing arm contactor in the bosch relay. Since it takes
little electrical control current to move the contact arm, this
becomes an easy task for the old overused headlight switch. New
fresh bigwire 12vdc is fed to the contact side of the bosch relay
and the output is sent to one head light. then the head light switch
is turned off the relay swing arm moves back to rest and the head
lights turn off. Note that at rest contact is made so care must be
taken when chosing the correct output terminal.

below is a good relay article
http://tinyurl.com/5hjxm

or
http://www.classictruckshop.com/clubs/ea...osch/relay
.htm

GregoryO'Connor
94ptRomolandCa