Author Topic: How did battery chargers rectify AC to DC before solid state diodes?  (Read 6752 times)

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Offline ConnecteurTopic starter

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I know about selenium and mercury rectifiers, but rechargeable batteries have been around a long time. How did people charge batteries from AC without resorting to such expensive rectifiers?
 

Offline bdunham7

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #1 on: April 18, 2021, 04:09:48 pm »
Did they charge them from AC?  There were DC generators and DC power in many places.

Early rectification systems included mechanical systems such as a set of contacts driven by a synchronous motor, regeneration system with a DC generator driven by an AC motor and electrochemical systems similar to an electrolytic capacitor except they were meant to break down and conduct, not store charge.  All of those were forgotten 15 minutes after silicon power rectifiers became available.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline geggi1

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #2 on: April 18, 2021, 04:32:05 pm »
There where tube diodes back in the day.
Selenum rectifiers where first invented in 1876.
https://en.wikipedia.org/wiki/Selenium_rectifier
Mercury rectifierers where  first invented at about the same time.
 

Offline vk6zgo

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #3 on: April 18, 2021, 04:38:19 pm »
I know about selenium and mercury rectifiers, but rechargeable batteries have been around a long time. How did people charge batteries from AC without resorting to such expensive rectifiers?

They used these things:-

https://www.radiomuseum.org/dsp_multipage_pdf.cfm?pdf=tungar_bulb_data_manual_52410.pdf

They are a mercury rectifier of sorts, but optimised for the simple battery charging job, & hence quite inexpensive.

Or they used "Copper-Oxide" rectifiers---these & Selenium rectifiers are hard to tell apart when you get to the larger ones--------they both have large "fins" for heat dissipation.(strictly speaking, they are "solid state")

Again, both were used in thousands throughout industry, so prices were not that high.

The "Tungar", Copper Oxide, & Selenium rectifiers were quite reliable, if lossy, so in the relatively low stress job done by most chargers, lasted for decades.

If you had a large battery bank to charge, a motor-generator could do the conversion.



 
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Online Mechatrommer

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #4 on: April 18, 2021, 04:45:20 pm »
How did people charge batteries from AC without resorting to such expensive rectifiers?
using 20 cents rectifier ic like this... https://lcsc.com/product-detail/Bridge-Rectifiers_DIOTEC-S380_C212805.html why bring up or even consider semi conductor from jurassic age?
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline Benta

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #5 on: April 18, 2021, 04:49:27 pm »
How did people charge batteries from AC without resorting to such expensive rectifiers?
using 20 cents rectifier ic like this... https://lcsc.com/product-detail/Bridge-Rectifiers_DIOTEC-S380_C212805.html why bring up or even consider semi conductor from jurassic age?

Unfriendly and beside the point.

If the OP is thinking automotive, dynamos were used for charging. Alternators didn't come into fashion before solid-state rectifiers were available at reasonable price.

 
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Offline JohnnyMalaria

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #6 on: April 18, 2021, 04:56:29 pm »
How did people charge batteries from AC without resorting to such expensive rectifiers?
using 20 cents rectifier ic like this... https://lcsc.com/product-detail/Bridge-Rectifiers_DIOTEC-S380_C212805.html why bring up or even consider semi conductor from jurassic age?

Topic title: How did battery chargers rectify AC to DC before solid state diodes|O
 
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Offline Jwillis

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #7 on: April 18, 2021, 05:39:42 pm »
Also you'll want to search Mechanical Regulator .Earlier ones had a  cut out (make or break) relay with a voltage regulator . Later ones included a current regulator .
 

Offline coppice

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #8 on: April 18, 2021, 06:04:53 pm »
I know about selenium and mercury rectifiers, but rechargeable batteries have been around a long time. How did people charge batteries from AC without resorting to such expensive rectifiers?
Selenium and copper oxide rectifiers, both crude forms of semiconductor diodes, were cheap.They performed poorly compared to modern silicon rectifiers, but they did a perfectly serviceable job in their day.
 

Online RoGeorge

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #9 on: April 18, 2021, 06:19:16 pm »
Mercury-arc rectifiers:



https://www.kemptonsteam.org/history/arc-rectifiers/
https://en.wikipedia.org/wiki/Mercury-arc_valve



Also featured in a video game level "Sniper Elite 4 - Magazzeno Facility: Destroy The Mercury Arc Rectifiers":

« Last Edit: April 18, 2021, 06:27:46 pm by RoGeorge »
 

Offline coppice

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #10 on: April 18, 2021, 06:36:31 pm »
Mercury-arc rectifiers:
Mercury arc rectifiers were for large scale use, and didn't like being moved around. They were mostly used for high voltages, too. There were small cheap resonant reed rectifiers, which avoided the mercury and the glass envelope, for really crude low voltage use, such as car battery chargers. Even at a low frequency like 50Hz or 60Hz it was difficult to get these things to make and break contact bang on the zero crossings, so the results were kinda nasty.
 

Offline james_s

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #11 on: April 18, 2021, 06:45:27 pm »
How did people charge batteries from AC without resorting to such expensive rectifiers?
using 20 cents rectifier ic like this... https://lcsc.com/product-detail/Bridge-Rectifiers_DIOTEC-S380_C212805.html why bring up or even consider semi conductor from jurassic age?


Did you even read the question? How is that even remotely helpful?

It's like someone asking how Roman chariots were built, and you tell them why even consider an ancient chariot, just go and buy a cheap bicycle  :palm:
 
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Offline ozcar

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #12 on: April 18, 2021, 08:34:32 pm »
Selenium and copper oxide rectifiers, both crude forms of semiconductor diodes, were cheap.They performed poorly compared to modern silicon rectifiers, but they did a perfectly serviceable job in their day.

I was a bit surprised to see how selenium rectifiers could be used. If you zoom in to the photo here, you can actually read the labels - "SenTerCel Selenium Rectifiers".

https://collection.sciencemuseumgroup.org.uk/objects/co538159/cascade-generator-built-at-the-cavendish-laboratory

I have seen the actual machine on display there in operation, close to 50 years ago.
 

Offline coppice

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #13 on: April 18, 2021, 08:53:19 pm »
Selenium and copper oxide rectifiers, both crude forms of semiconductor diodes, were cheap.They performed poorly compared to modern silicon rectifiers, but they did a perfectly serviceable job in their day.

I was a bit surprised to see how selenium rectifiers could be used. If you zoom in to the photo here, you can actually read the labels - "SenTerCel Selenium Rectifiers".

https://collection.sciencemuseumgroup.org.uk/objects/co538159/cascade-generator-built-at-the-cavendish-laboratory

I have seen the actual machine on display there in operation, close to 50 years ago.
Look in lots of electrical products from the 1950s, including battery chargers, and you will find something like https://en.wikipedia.org/wiki/Selenium_rectifier#/media/File:Selenium_Rectifier.jpg . Those finned rectifiers were commonplace. Sometimes they were selenium. Sometimes they were copper oxide.
 

Offline ozcar

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #14 on: April 18, 2021, 10:04:38 pm »
Selenium and copper oxide rectifiers, both crude forms of semiconductor diodes, were cheap.They performed poorly compared to modern silicon rectifiers, but they did a perfectly serviceable job in their day.

I was a bit surprised to see how selenium rectifiers could be used. If you zoom in to the photo here, you can actually read the labels - "SenTerCel Selenium Rectifiers".

https://collection.sciencemuseumgroup.org.uk/objects/co538159/cascade-generator-built-at-the-cavendish-laboratory

I have seen the actual machine on display there in operation, close to 50 years ago.
Look in lots of electrical products from the 1950s, including battery chargers, and you will find something like https://en.wikipedia.org/wiki/Selenium_rectifier#/media/File:Selenium_Rectifier.jpg . Those finned rectifiers were commonplace. Sometimes they were selenium. Sometimes they were copper oxide.

No fins on the ones I gave a link to. Not sure of the internal construction, but they had to be good for a few hundred kV each.
 

Offline vk6zgo

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #15 on: April 18, 2021, 11:08:35 pm »
Selenium and copper oxide rectifiers, both crude forms of semiconductor diodes, were cheap.They performed poorly compared to modern silicon rectifiers, but they did a perfectly serviceable job in their day.

I was a bit surprised to see how selenium rectifiers could be used. If you zoom in to the photo here, you can actually read the labels - "SenTerCel Selenium Rectifiers".

https://collection.sciencemuseumgroup.org.uk/objects/co538159/cascade-generator-built-at-the-cavendish-laboratory

I have seen the actual machine on display there in operation, close to 50 years ago.
Look in lots of electrical products from the 1950s, including battery chargers, and you will find something like https://en.wikipedia.org/wiki/Selenium_rectifier#/media/File:Selenium_Rectifier.jpg . Those finned rectifiers were commonplace. Sometimes they were selenium. Sometimes they were copper oxide.

No fins on the ones I gave a link to. Not sure of the internal construction, but they had to be good for a few hundred kV each.

I used the term "fins" because it was closer to what a modern person would think upon seeing one.
We would have called them "plates" back in the day.

The active junctions of copper oxide or selenium rectifiers of the construction were restricted to the small "washer like" area which was actually in compression.(see the photos in your link)
The large plates were for heat dissipation, as they were lossy devices.

Small selenium devices used in radio receivers, etc came in quite different packages, with the "plates" either diminished in size, or missing altogether.

The famous "Sentercel" high voltage rectifiers used in some earlier Oscilloscopes were stacked selenium devices.
 

Offline vk6zgo

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #16 on: April 18, 2021, 11:21:14 pm »
An interesting point about Tungar rectifiers:-

They could "self protect" against quite severe overloads.

I once inadverently shorted the output of the 1930s 6v battery charger I used to charge the battery of my old prewar Chev.
I thought I had "killed" it, but the Tungar glowed brightly with the short on, & returned to normal operation when it was removed.

A silicon, selenium, or copper oxide rectifier would have been toast!

I was having these adventures in the very early 1960s, the car was from 1936, & the charger, a few years older than that!

My old work had a very large Tungar charger which was probably of a similar vintage.
 

Offline Renate

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #17 on: April 19, 2021, 02:01:08 am »
Some of the old "vibrators" in old tube car radios did synchronous rectification with extra contacts.
The vibrator chopped the 12 V to feed a step up transformer.
I think most used a tube rectifier though.
 

Offline Martian Tech

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Online Mechatrommer

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #19 on: April 19, 2021, 11:32:54 am »
It's like someone asking how Roman chariots were built, and you tell them why even consider an ancient chariot, just go and buy a cheap bicycle  :palm:
read again the OP.. he asked how to build a roman chariot, without using expensive roman chariot.

Topic title: How did battery chargers rectify AC to DC before solid state diodes|O
one of the earlier (later?) suggestion is using car alternator... here we go...



it should be "helpful"? if we dont consider anything inside the dotted box (before B+) as solid state diodes ;D

Selenium and copper oxide rectifiers, both crude forms of semiconductor diodes, were cheap.They performed poorly compared to modern silicon rectifiers, but they did a perfectly serviceable job in their day.
ditto!... whats the purpose of placing solid state diodes afterward anyway? if its already rectified to DC? just to drop few multiples of 0.3V? to avoid over voltage trickle charge level? ;D i havent seen that kind of trick recently done by factories... except with my own very crude and unintelligent charger ;D ymmv.
« Last Edit: April 19, 2021, 11:44:42 am by Mechatrommer »
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline coppice

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #20 on: April 19, 2021, 01:49:01 pm »
Selenium and copper oxide rectifiers, both crude forms of semiconductor diodes, were cheap.They performed poorly compared to modern silicon rectifiers, but they did a perfectly serviceable job in their day.

I was a bit surprised to see how selenium rectifiers could be used. If you zoom in to the photo here, you can actually read the labels - "SenTerCel Selenium Rectifiers".

https://collection.sciencemuseumgroup.org.uk/objects/co538159/cascade-generator-built-at-the-cavendish-laboratory

I have seen the actual machine on display there in operation, close to 50 years ago.
Look in lots of electrical products from the 1950s, including battery chargers, and you will find something like https://en.wikipedia.org/wiki/Selenium_rectifier#/media/File:Selenium_Rectifier.jpg . Those finned rectifiers were commonplace. Sometimes they were selenium. Sometimes they were copper oxide.

No fins on the ones I gave a link to. Not sure of the internal construction, but they had to be good for a few hundred kV each.
I think the huge ones you linked to were for pulsed operation. Selenium and copper oxide rectifiers got quite hot in continuous operation, so they were usually mounted on finned heat sink assemblies for good cooling.
 

Offline Stray Electron

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #21 on: April 19, 2021, 01:53:04 pm »
  The earliest rectifiers that I know were pools of liquid mercury with a rod hanging over them and with an arc to the pool. Using a large pool they could handle large amounts of current (industrial scale). These were shortly replaced with mercury vapor rectifier tubes and those were still in use into the 1970s.  The MV rectifier tubes had a bad reputation because they generated UV-C radiation so they needed to be used in an enclosed cabinet but you can well imagine the hazards of not only the UV-C radiation but the mercury vapor that was added into the room air by mercury pool rectifiers!

  I used to have a book on the early NYC subway system and, IIRC, it explained the pool rectifiers and had pictures of them. The book 'Electric Circuits and Machines' by B. L. Robertson has a good description of MV rectifier tubes. My copy is dated 1949 but is still useful!
 

Offline Renate

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #22 on: April 19, 2021, 02:12:01 pm »
He asked how to build a roman chariot...
It's interesting to note that Roman chariots actually used a pair of brushless DC motors.
The horses were just for show.
 
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Offline Stray Electron

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #23 on: April 19, 2021, 02:12:19 pm »
I know about selenium and mercury rectifiers, but rechargeable batteries have been around a long time. How did people charge batteries from AC without resorting to such expensive rectifiers?

  Before the REA (1936) and in the 1920s, 30s and even the 40s, many rural people in the US had their own wind turbines and they put out 36(?) VDC directly. Operating radios and a few electric lights in very rural locations that didn't have commercial power, was a very popular justification for installing a wind turbine. When I lived in rural Virginia in the 1970s these were still in demand! See http://www.jacobswind.net/history If you lived in a city that had AC power, other early devices are included AC powered motor driven DC generators. I just saw a NICE one from the 1920s in a surplus store near here. I'll try to get pictures of it if it's still there. Then there were also mercury vapor rectifier tubes if you needed large amounts of power or high voltages. But Selenium, copper oxide and other solid state rectifiers were a huge improvement over any of those!
 

Offline coppice

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Re: How did battery chargers rectify AC to DC before solid state diodes?
« Reply #24 on: April 19, 2021, 02:13:13 pm »
  The earliest rectifiers that I know were pools of liquid mercury with a rod hanging over them and with an arc to the pool. Using a large pool they could handle large amounts of current (industrial scale). These were shortly replaced with mercury vapor rectifier tubes and those were still in use into the 1970s.  The MV rectifier tubes had a bad reputation because they generated UV-C radiation so they needed to be used in an enclosed cabinet but you can well imagine the hazards of not only the UV-C radiation but the mercury vapor that was added into the room air by mercury pool rectifiers!

  I used to have a book on the early NYC subway system and, IIRC, it explained the pool rectifiers and had pictures of them. The book 'Electric Circuits and Machines' by B. L. Robertson has a good description of MV rectifier tubes. My copy is dated 1949 but is still useful!
Most mercury rectifiers were of the pool + arc type. They were common in the 1950s, but pretty much gone by the end of 1960s, because silicon rectifiers developed so fast and outclassed them. British Rail introduced trains running from 25kV AC at the beginning of the 1960s, using mercury arc rectifiers in the trains, and they were a disaster. Those rectifiers worked well in fixed locations, but very poorly with the mercury sloshing about on the move. Luckily, silicon rectifiers came to the rescue in the nick of time, and the trains ended up working well.
 


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