Starter relay and huge power consumption?

[Commander Kinsey]

Are you from the deep south? That's down the way on the map.

[Commander Kinsey]

Even a £5 meter has that function.

I bought a Chinese battery charger which has mains voltage leads with about 0.1mm thick wire inside. I guess that's also the fuse. And the plug has plastic prongs! Painted with conductive paint! If you plug it in with the socket turned on, there's a little spark to charge the bulk capacitor presumably. Doing this many times causes the paint to burn off. One day it won't get any power. I could change the plug I suppose, if I can get that tiny thin wire into the grubscrews.

[trader_4]

Yes, but there is a huge change in temp of the filament from room temp to glowing hot at operating temp. A relay coil, not so much.

[Dean Hoffman]

Nah, I've spent my life in Nebraska. I did travel to the southeast U.S. on vacation. Maybe the pretty women down there corrupted my mind.

[Fredxx]

If a term is in common parlance it becomes right.

[Clare Snyder]

Not true - a "contactor" is a solenoid. Only solenoids used on a "pre-engage"starter activate the drive - solenoides used with "inertia" starters do not. As for starter solenoides vs "battery contactors" - SOME starter solenoids have 2 coils. One connects from the "S" terminal to the ground and the other connects from the "S" terminal to the "M" terminal (big post that connects to the starter) while the battery connects to the "B" terminal (big post that connects to the starter). The S to M winding is a high current winding that is the "pull in" winding and passes enough current to get the starter slowly turning - while the S to Ground winding is the low current "hold" winding.

ALL "pre engage" solenoids work this way - and some "contactor" type starter solenoids as well.

[Clare Snyder]

RV, likely - anyhing with a "coach battery". Boats, busses, ambulances, and some other emergency vehicles as well.

[micky]

My experience is limited, but GM solenoids, at least until 1973 and maybe forever move the gear that engages the flywheel, and at the end of the travel, the other end of the solenoid connects the power to the starter motor.

I don't think I've had any problems with the starter on 84, 88, or 95 Lebarons, or the 2000 or 2005 Solara, so I know nothing recent.

[Brian Gaff (Sofa]

Or to put it another way, maybe inside it really is a solenoid, though I doubt it. If you feel it looks like a relay, , then you do really need to look at the current and see. I remember a device on our really ancient Austin car back in the 1970s where the device included contacts, but had a little slot in it that engaged with a lever which actually moved. No idea what it was doing, but the point was it was in fact a solonoid with relay contacts, but its main job appeared to be moving this little lever. Brian

[Brian Gaff (Sofa]

Are you sure there is not a slot in it somewhere as I said in an earlier reply? Otherwise it seems to be a little weird in the extreme. The only other thing I can thing of is that it is prone to high vibration when it is engaged and the constructions makes sure the contacts stay closed during that time. Brian

[trader_4]

Technically any relay is a solenoid, but the correct term is still relay. In the case of auto starters, they were called starter solenoids because initially they did more than just a relay function, they also moved the bendix that engaged the flywheel. They were a relay plus an actuator. Relays are not commonly referred to as a solenoid, certainly not by anyone knowledgeable in the field. For that matter, contactor is silly term too, those are just relays and more correctly called that. Those and auto relays that are just relays should be called relays to be consistent with terminology. Would you call an AC compressor relay or a fuel pump relay a solenoid?

[gfretwell]

Generally a high current AC relay is called a contactor but I agree it is still the same thing electrically.

[Clare Snyder]

Basically the difference between a "relay" and a "solenoid switch" is a relay has a fixed magnetic core that attracts the "armature" - or spring loaded plate that carries one contact, contacting the fixed contact when actuated (for a normally open relay) or disconnects for a normally closed relay.

A "solenoid switch" on the other hand has 2 (or more) fixed terminals and a moveable armature with a moving "passive" contact that bridges the terminals when energized. It CAN also be used to move something mechanically, like a pre-engage starter drive. A solenoid switch uses a compression spring to force the contacts open when disengaged. A relay generally has a combination hinge/spring but can also have a hinge and tension coil spring. Due to the difference in construction a "solenoid switch" is generally more robust than a "relay" but also draws more current.

There are "intermittent" rated solenoid switches - generally used as starter solenoids - and "constant duty" solenoid switches generally used as main battery contactors.

Constant duty solenoid switches for 12 volt applications are generally in the range of 15 to 25 ohms, while intermittent duty solenoid switches run 2.5 to 3.5 ohms.

[gfretwell]

By that definition contactors fall into the solenoid category but I have never heard it used in industrial applications. The solenoid thing seems to just be vehicles. It is like a "Condenser". Nobody but mechanics call capacitors condensers. I think a lot is left over from the Henry Ford days.

[Commander Kinsey]

No slot. I think it's a strong spring to stop arcing when disengaging. And maybe the vibration too.

[Commander Kinsey]

What did it condense? A capacitor stores, it does not condense.

[Commander Kinsey]

Indeed, but I wasn't being accurate, just determining that there's no way it would want to dissipate that much heat continuously.

[makolber]

Some car solenoids have two coils, a high current coil that is initially energized to get the armature moving, and then a smaller lower current coil to hold it in place. The high current coil was wired across the contacts so current flowed through the coil to the starter motor. Once the contacts closed, the coil was shorted and the starter is energized directly. M

[gfretwell]

Don't argue with me. Talk to the mechanics that called them condensers for the last 100 years. These days they are pretty rare in cars since everything is electronic but you probably have one in your lawn mower.

[trader_4]

This explains the origin:

"Early capacitors were known as condensers, a term that is still occasionally used today, particularly in high power applications, such as automotive systems. The term was first used for this purpose by Alessandro Volta in 1782, with reference to the device's ability to store a higher density of electric charge than was possible with an isolated conductor.[12][1] The term became deprecated because of the ambiguous meaning of steam condenser, with capacitor becoming the recommended term from 1926.[13]"

Early experiments they connected at crude voltage sourse to a Leyden jar and charged it up. You then got a bigger spark, more electricity flow than you'd get from the source itself. Hence it looks like they were attributing this to the jar condensing the electricity coming out of the voltage source.