Hope the photo or link shows up... the site wouldn't let me load one on here... says "Sorry, the board attachment quota has been reached"... whatever that means. I did a photobucket link....instead.

Back to the subject at hand. I've had this 32 volt direct current generator for a long time. It was MK&T railroad property. Onan 2 cylinder water cooled engine direct coupled to a Fairbanks Morse generator. Crank start, or can use the generator as a starting motor, and has a magneto ignition. The handles fold out of the way, it has pnuematic tires and it at one time had sheet metal sides to enclose it. The crank handle was still in it's little inside hiding place when I got it... I have had it running.... 20 years ago. Gasoline powered.

What I am anxious to find out is what exactly ran on 32vdc. I am thinking shore power for passenger cars that get left at at station or platform away from the power supplied there.

Didn't old railroad passenger equipment run on 32vdc? Fans, lights and what have you?

I conferred with a retired MKT carman and he says he used the exact same machine to thaw frozen water piping many years ago... but he can't say what the original use was.

Yes, steam era passenger cars had 32-volt battery powered lamps. Axle driven generators (or possibly your generator) charged the batteries, many older cars at museums still have the electrical equipment visible under the cars. A couple outfits still carry the bulbs as some older boats also use that voltage.

http://www.grainger.com/product/GE-LIGH ... s_pp=false

Aircraft use 12 or 14 or 28DC and 120AC at 400HZ.

Most everything on the train was 32 volts. Nowadays it's all twice that, 64 volts. Note these voltages are nominal, a 64 volt system ranges from a bit less then 64 when the battery is fully discharged (say 60 volts or so) on up to 78 volts or so when the system is at peak charge with the charger running. so 30 volts to 39 volts on your charger.

That is a 16 cell system, which is not an easy number to come up with unless you buy railroad batteries. standard car batteries are 3 or 6 cell, so you can't add that up to 16. You can get golf cart and a specialty car battery in 4 cell at a good battery shop, those are the size of car batteries, you need 4 in series. You can get 4 cell rail batteries, they look about like 3 car batteries end to end, 250 pounds each. unitized 32v rail batteries are running at least 1000 pounds each.

I do have 18~ 2 volt railroad cells.... modern, about 10 years old. I have enough to make 36 in 2 volt increments. They were takeoffs from the signal system. They change them out at 10 year intervals~ government edict.

I have them set up in parallel... 3 sets of 6 for 12 volts per bank being charged by solar panels on my shop roof. I use the power to run things in the shop, and have them also connected to an inverter to make 120v.a.c..

Like I said, I just wanted to get some sort of verification that this could have had something to do with powering passenger cars while they stood still. I knew it was railroad related by where it came from, just wasn't sure in what capacity.

It was not uncommon for machines similar to yours to be used to charge the batteries on a 32V DC passenger car when the car was in the yard or standing in the station. Many 32V postwar cars had axle generators that could also be powered from a 220V wayside power source, in which case the generator would charge the batteries the same way it would going down the track. But some RR's, such as MKT and the AT&SF, had smaller generators that were belt driven and did not have stand-by power capability, so their version of stand-by power was the portable 32V battery charger. However, the chargers I am familiar with were not engine driven like yours, but were powered by 220V AC wayside power.

In addition to 32V and 64V, some cars used 110V DC. Looking at a list of generators offered by Safety (brand) and there were all three voltages in a variety of capacities. I think prewar tended to be 32V.

Steve

Thanks for all the replies. I am satisfied with the answers and believe I am on the right trail.

Steam locomotive dynamos put out 32 VDC. This tool could have use in testing and repairing locomotive dynamos and wiring. I've used 24 volt battery chargers for that purpose.

dave

32 volts was the standard for passenger car circuits. When Santa Fe rebuilt their cabooses in the 1969-70 period (the CE-1/CE-2 program) the former 12-volt electrical systems were changed to 32 volts. Since 32 volt radios were not readily available, they were fitted with 12-volt radios, probably Motorola Motrans. The radio installation included a pair of large resistors, one for receive mode and one for transmitting, switched by a relay connected to the "push to talk" circuit.
64-70-72 volts was and is the standard voltage for locomotive starting circuits. Some of the early Alco diesels (and possibly Baldwins) used 110-volt batteries. Light bulbs and radios were and probably still are made in 70-volt models.
Smaller diesels, especially those built for industrial service and equipped with engines designed for highway truck service may have 24-volt systems. At OERM we have a GE 44-ton switcher with four motors and a 70 volt battery, and a 45-ton model (with siderods) that has a 24 volt battery.

The nominal 32VDC system is still the standard for transit cars built today. The voltage is generally rated at 37.5V for fully charged batteries, but the standard says all equipment must function over a very wide range above and below that, typically 28-42V and sometimes as high as 48V and as low as 24V.

The 32V system was also the standard for virtually all industrial diesel locos. Anything in this class that is not now 32V was likely converted at some point in order to make use of automotive 12V or 24V batteries, as the 8V batteries aren't exactly a neighborhood auto parts store item. If you're located anywhere that commercial waterways are nearby you'll also find that towboats and such also use the 32V system. That's why battery warehouses in the Pittsburgh area stock those odd 8V batteries. Larger diesels are generally nominal 64V, actual voltage around 75V, but some used 110VDC systems.

The lamps for diesels are usually rated at 30V, 32V, or 34V. On GE industrial diesels with the 200W 30V sealed beam lamps there is always a resistance in series with the bulb, or they'd have a very short life at 37.5V.

This is interesting. I have never seen a generator like this, but it stands to reason that railroads would have had them for charging passenger cars at stations where no 32-volt shore power was available. One possible use would have been keeping a Pullman car charged at an intermediate station where a standing car was boarded in the evening and attached to a through train during the night. I don't know if this unit would have been big enough to power a 32-volt electric air conditioner, but it would have kept the lights and fans working. (Many pre-war Pullmans had axle-driven compressors, and I believe there were portable motors to drive those when stationary, too.)

The secret life of 32V DC:

We once found a military portable 32-volt generator at our local surplus depot, with a 1-cylinder Wisconsin. We never learned what the Army did with 32 volts.

One of the laboratory buildings at Michigan State University was wired for 32 volts DC as late as the 1970s. We were told the steady direct current was needed for some sensitive scientific gear. It was weird to see a building equipped with Safety Co. hardware.

Aarne Frobom
Anode, Michigan

At one time there was an MKT passenger car here in the yards that had been converted to MofW use. Crawling up the stairs into the vestibule a long time ago I remember looking up overhead to the ceiling and remember seeing an electric receptacle... it was about 4 inches wide and about an inch thick.

It had two blades in it....side by side with a divider... kind of what you see on industrial electric forklift charger receptacles.

Was that for an electrical "MU" cable to get DC from car to car....what other two conductor electrical system would there have been. If each car had an axle driven generator, would there actually be a need to MU the cars together?

On a side note about locomotive "lamps" today. The new step lights, number board lights, and other walkway lights are all LED instead of the old standby incandescent lamp that's been used since forever.

A little secret.... they will operate on AC or DC, from 24 volts on up to 74 volts... with no change in operating characteristics. In other words, you can light them up with a doorbell transformer.

That was probably for emergencies, if 1 car of a pair had a bad power supply. Possibly, it could also be used if there were more cars in a parked string than shore power connections.
For the very few railroads like CNJ that put an electric generator, often powered from the steam heat line, in the tender or baggage car, the cable for Head End Power would probably be different.

The Onan engine is likely what was called a W2C and the generator may actually have been built by Onan with the FM name on it. I have a late 1940's FM catolog from back when our family business was a FM dealer. It shows engine generators that are obviously built by Onan and sold under the FM name. I have at least one small Onan built unit in my collection with FM nameplate. 32volt DC was not exclusively a railroad thing. Delco, Onan and Kohler built 32 volt light plants to charge batteries at remote ranches/sites before rural electrification took off. Delco made a line of small 32 volt dc appliances that they sold with their package systems. I have in my collection a 1500watt water cooled Kohler with tiny 4 cyl. engine set up for 32 volt battery charging that came from Trion Crk. Ranch in Hells Canyon on the Snake River. I understand it charged a bank of 2 volt glass jar batteries. Similarly I have worked at another remote place that not too many years ago still had it's 32 volt system in place with glass jar batteries, 32 volt 1000 watt FM light plant built by Onan and running on LP gas, a 32volt wind charger on a tower and the electric motor powering the deep well sucker rod pump for water was 32 volt running off the battery bank.
Upon a little further research, the unit inquired about is shown in my FM catolog and price list from 1947. It is likely a model W32-35-6 rated for 3500 watts, weighs 656lbs. and list price at that time was $895.

The use of these jumpers between every car in a train was a common practice on Canadian National. No doubt, it went a long way toward equalizing the load, voltage, and battery condition through the entire train.

Some roads may not have bothered.

Steve Hunter