Temp sender

[john grady]

Bob, do your lights brighten when you rev engine? Or dim when you put blower on high? Voltage regulator is mostly all about charging battery. Battery volts go from what, 12 to 14 depending on what is going on (6-7 on 6V systems)

That being said, it is correct as staed above that stock 6V 50 stude has no thermal gauge regulator. Maybe they just let gauges move, only accurate when engine is running/battery charged? None of these are exactly precison instruments..( aka GM gas gauge syndrome..you run out and it reads 1/8).

I do not know about stude stock 12v. But I do know Ford and 50 Stude both read full scale with a steady 5 V on them. Maybe why tank ohms do not go to zero when full, on ford, from old 6 v system?(still loses ~ 1 volt at F ) still some drop at sensor even when full..

The point of all this is to try to understand it exactly, instead of guesses and opinions. I have no personal stake in how the hell it works,i just want to know the "WHY" .

[john grady]

ley, does it say how gauges without regulator work? They have a compensation built in?

[leyrret]

I studied this stuff years ago and memory is hazy. Don't have books here. Whether a gauge needs regulation I believe is in the design.
A bi-metal strip type(called thermostatic gauge) with heating coil would be voltage sensitive at a given sensor resistance because the current would vary by voltage which would vary heat applied to bi-metallic strip and vary gauge reading. Magnetic gauge generally uses two coils wired in parallel to source voltage. One coil going to ground internally and the other to ground through sender. Voltage variation
should effect the magnetic fields of both coils to the same proportion at any given sensor resistance and not effect gauge reading. I'm sure there are many variations and depending design may or may not need a regulator. This is from memory but I think I got it about right.

[Jeff_H]

This thread may help too:

http://forum.studebakerdriversclub.c...TOPIC_ID=20068



Jeff in ND

'53 Champion Hardtop

[john grady]

thanks Jeff and ley..you can see all the confusion about same issue in that thread. Jeff, your measurements reflect what i know so far ( see Ford stuff above) Ley, 51 are definitely thermal gauges, not two coils. I do not remember seeing two thermal bimetals, but that may be possible?? . But i think you are 100% correct in the early gauges worked like that. Thermal gauges do show a "bumpy ride" as they move, that averages gas sloshing etc, while coil types will show you the sloshing, and "jump right up" with no delay when you turn on key. ..

You could get away with not regulating coils maybe, but I would think E sq / R would kill you on bimetal. 6=36, 7v = 49 . I have seen all the needles , even on 97 grand cherokee move at once sometimes.. regulator sticking?

We need someone with some parts around to measure. I will when next time i get into #2 stude (50 2dr champ)

[leyrret]

I did a bit more checking found a little more information. It appears all earlier gauges were variable voltage. King-Seely switched
to constant voltage around 1957. The earlier gauges do not uses a variable resistance in the sender. The sender has a coil and bi-metal strip similar to gauge unit with a set of contacts on one end. The two are connected in series so same current goes through both. The fuel
and oil sender vary tension on strip so more or less current is required to break contacts. Since same current is going through gauge coil
needle position changes with change in current flow. The temp sender uses engine heat to reduce amount of current needed. This type temp gauge is is distinguished by the fact it will register hot when key is in off position. The later version uses 5.5 v regulator(pulsating voltage)with the resistance type sender. You may be able to use a regulator with an earlier gauge and use the later type sender if you can find one with the required resistance for the gauge.

[gordr]

None of the Studebaker gauges have voltage regulators. They are used in many Brand X cars, though.

Six volt or twelve volt, all Studebaker gauges (at least POST-war) have two electrically-heated bimetal strips to deflect the needle. One bimetal strip gets fed straight system voltage from the accessory terminal on the ignition switch, and is grounded in the case of the gauge. The other is fed from the dame source, but is grounded through the sending unit. The two bimetals act in opposition to one another. A change in system voltage will have an equal but opposite effect on each bimetal, so the pointer will not move. A change in resistance of the sending unit changes the current in only ONE bimetal, so the pointer moves.

Six volt gauges and twelve volt gauges use different sending units, and will not work properly with the wrong sending unit, not even close.

If one is converting a six-volt car to twelve volts, the simplest solution for the gauges is to purchase a solid-state voltage regulator, like a Runtz, for the gauges.

Gord Richmond, within Weasel range of the Alberta Badlands

[leyrret]

Not doubting your word as I have never worked on old Stude gauges. I'm only going by reference material. The only reference(books back to 1944) I see to a dual coil/bi-metal strip thermostatic gauge is a is an Auto-lite fuel gauge which uses two wires to the sender. The ones in my hawk were I believe Stewart Warner magnetic gauges

[john grady]

gordr...if it has two, that would make sense ..and it may have. I was less concerned with how gauge operated at the time vs. impact on gauge of voltage changes on car, than what full scale and zero required for ohms,as all stude gauges are i believe thermal..you can tell by the way it comes up, rather slowly and "jerkily" . If stock stude has no regulator and that design approach used on 12V, and 6v , then they are two totally different deigns. One can see from all this how Ford did a smart thing.. maybe Chrysler too... using same 6V gauges and senders on 12 V by using a new 12V to 5V regulator,as they already had one for 5 or 5.5 on 6V. and Ley, I bet your hawk was like that? Magnetic gauges would jump instantly up like an ammeter.

Thread kind of veered off, but all this is good to get out there.

I think what I used is a 7805 National semiconductor IC regulator to get +5V for 6V gauges on +12V car ; I used back of instrument (1951) case for heat sink ,4/40 screw + nut into it you do not need aluminum fins etc. I had whole unit out of car when i did this work, to repaint needles etc. the IC's are about 1$ , good for more than enough to run gauges, no problems..except 51 sending unit is NG. I hate to pay 50$ for one, a rip off.

You may have to insulate tab of IC , they make mounting kits with mica washers.. Note 5V is regulated then, even on 6V car, may improve gauges anyway.

I needed to be sure it worked, led to test with 5V, ; 5V DC full on full time will bring gauge up to full mark or hot end , zero V I left alone (gauge at rest)