Solenoids

[delmarrey]

Originally Posted by DeepFrz

Yes, that makes sense. I guess the difference is in the details. A small solenoid activated by the start switch to pull in the large solenoid that activates the starter itself. Have never seen it but this alternative would be more reliable than a simple relay to activate the starter solenoid. Generally solenoids are very reliable and long lived.

The problem with the larger solenoids is the contacts get fried over time but are usually rebuildable due to their costs.

[Brent Swain]

The hand push, bypass the solenoid option is very important, if you are trying to start with a low battery.

[capngeo]

Originally Posted by Brent Swain

The hand push, bypass the solenoid option is very important, if you are trying to start with a low battery.

Here's my low battery starting device

[osirissail]

Bit of a word problem here - usually a device is named a "solenoid" when it is necessary to convert electrical energy into a physical linear motion such as operating a "plunger" in a starter solenoid that physically moves the Bendix gear and also engages large copper contacts that allow very large amperages to flow to the starter motor.
- - "Relays" are similar devices but the plunger only closes a very light weight set of contacts that allow a large electrical current to be controlled by a very small electrical current. That is, the starter switch uses very little electrical power to close the relay - which enables the use of small electrical wiring. Then larger electrical wiring from the relay powers the solenoid which physically engages the starter motor to the flywheel and closes large contacts to allow huge amounts of power from the battery to rotate the starter motor.
- - Modern cars and boats make use of "solid state" relays and thin wiring to power larger relays downstream close to the actual high power load. This all saves significant money and adds additional layers of safety to the wiring system.

[fairbank56]

The gear on a starter that engages the flywheel is called a pinion gear. Many many years ago, starters used a bendix assembly to engage the pinion gear. Modern starters use a solenoid to engage the gear. Relays do not use a plunger as the core of the coil is fixed. The contacts of a relay are attached to a movable arm who's movement is activated by the magnetic force of the coil.

Eric

[delmarrey]

Originally Posted by osirissail

Bit of a word problem here - usually a device is named a "solenoid" when it is necessary to convert electrical energy into a physical linear motion such as operating a "plunger" in a starter solenoid that physically moves the Bendix gear and also engages large copper contacts that allow very large amperages to flow to the starter motor.
- - "Relays" are similar devices but the plunger only closes a very light weight set of contacts that allow a large electrical current to be controlled by a very small electrical current. That is, the starter switch uses very little electrical power to close the relay - which enables the use of small electrical wiring. Then larger electrical wiring from the relay powers the solenoid which physically engages the starter motor to the flywheel and closes large contacts to allow huge amounts of power from the battery to rotate the starter motor.
- - Modern cars and boats make use of "solid state" relays and thin wiring to power larger relays downstream close to the actual high power load. This all saves significant money and adds additional layers of safety to the wiring system.

You are mainly right! Maybe pictures will help. And then there are reed switches/relays.
.

[cal40john]

Originally Posted by osirissail

Bit of a word problem here - usually a device is named a "solenoid" when it is necessary to convert electrical energy into a physical linear motion such as operating a "plunger" in a starter solenoid that physically moves the Bendix gear and also engages large copper contacts that allow very large amperages to flow to the starter motor.
- - "Relays" are similar devices but the plunger only closes a very light weight set of contacts that allow a large electrical current to be controlled by a very small electrical current. That is, the starter switch uses very little electrical power to close the relay - which enables the use of small electrical wiring. Then larger electrical wiring from the relay powers the solenoid which physically engages the starter motor to the flywheel and closes large contacts to allow huge amounts of power from the battery to rotate the starter motor.
- - Modern cars and boats make use of "solid state" relays and thin wiring to power larger relays downstream close to the actual high power load. This all saves significant money and adds additional layers of safety to the wiring system.

There seem to be many definitions out there. I like this one because it explains why the thing I bought to cross connect my batteries is called a solenoid by Cole Hersee and not a relay.

From:
RELAYS
The RELAY is a device that acts upon the same fundamental principle as the solenoid. The difference between a relay and a solenoid is that a relay does not have a movable core (plunger) while the solenoid does.

So a solenoid is a coil with a core that moves performing a mechanical action, this could be just operating electrical contacts.

John

[delmarrey]

BTW a rely is also a form of voltage regulator.

By producing a certain number of wraps around the coil it will determine how much voltage the coil needs to pull in the contact. And then by adjust the spring tension the voltage can be adjusted up or down by 10th of a volt.
The voltage runs through the coil, when volts gets below a certain amount the coil releases causing the contacts to engage, energizing the alternator and charging the batteries. We use to set these at 14.7 volts but I believe that has been dropped to 13.6 V now.

This is how we use to adjust the voltage regulators in the old days Now it's all electronic but even so some still have pot switches to make slight or factory adjustments.


.

[JiffyLube]

We have two solenoids for our Pathfinder engine that are partially wired together. One assists the starter, and the other for the glow plugs.

[SV Demeter]

Jiffy I have the same for my Perkins 4154. There is a relay for the starter solenoid and another solenoid for the glow plugs. (okay tecnically that solenoid is being used as a relay too).

[Vasco]

My Yanmar 4JH3E has a solenoid and another one they call a slave solenoid. I guess this is to help solve the Yanmar press the starter nothing happens problem. However it didn't help me, the slave kept sticking and I'd have to go down below and whack it. Finally replaced it.

Winter tomorrow, I gotta get out of Florida and over to the Bahamas.