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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Thu Jan 10, 2019 12:18 am 

Joined: Tue Jul 10, 2012 3:51 pm
Posts: 9
Very interesting reading this thread. The ideas here are amazing.

I like the idea of the 600V to 120/240 VAC converter and an automatic battery charger. Safety from overcharging, producing dangerous gas, etc. is important IMO, when you have visitors on the cars. You can even buy an automatic battery charger circuit board 120/240VAC to DC (adjustable) on eBay for a few bucks. Not overly recommending it, but it is possible.

[EDIT] Here is a link for an adjustable 12-36VDC battery lo/hi voltage cutoff circuit:
https://www.ebay.com/itm/XH-M609-DC-12V ... 3741330175

At $4.99 It should be within anyone's budget :).


One important consideration for the Edison batteries - they have a negative temperature coefficient. That is as they charge up their internal resistance decreases. Thus a simple constant voltage charger circuit will "run away" and overload/overcharge them. On the old Waukesha Enginators, they had a separate panel specifically for when Edison batteries were used.

----
I have 4 8V lead acid golf cart batteries that are charged by a Waukesha Enginator (running) or a transformer/rectifier (station power). The car is the old Milwaukee Road Dynamometer car at the Illinois Railway Museum.


Last edited by warren032 on Fri Jan 11, 2019 12:37 pm, edited 1 time in total.

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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Thu Jan 10, 2019 10:55 am 

Joined: Thu Oct 08, 2015 11:54 am
Posts: 466
Location: Orrville, OH
This is waaaaay out of my league but I'll throw something similar out there that may be workable or get you thinking....

Start with a 600 to 36 volt converter something like: https://absopulse.com/750vdc-high-input-voltage-railway-dc-dc-converters-transit-mining-vehicles/. Much smaller package. This one may/may not have the needed current available, don't know your requirements. No clue on the cost, though. Could be way out of line with your budget.

Automatic charging circuits are relatively simple affairs once you get past the initial power supply portion. If you have an electronics guru or technical school that'll take that portion on, you might be cooking with gas.

Just a thought...

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Eric Schlentner
ORHS Car Knocker & Gandy Dancer
http://www.orrvillerailroad.com


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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Fri Jan 11, 2019 10:49 pm 

Joined: Fri Mar 14, 2014 11:44 pm
Posts: 48
OK, my two cents, again.

If you are a *museum* then part of the mission is to preserve, to the extent possible, the original
historic fabric. To me, that also includes preserving the obsolete and inefficient technology of the
day.

Solutions that involve solid-state converters and other modern electrical components might be the
best answer for a transit agency, tourist railway, or "heritage" trolley operation where the primary
mission is not historic authenticity.

If the original charging system for these cars was M-G, the best practice from a museum standpoint
is to either rewind the M-G, or as one poster suggested, get an M-G from a PCC car (there are many
of these out there). Then you'll have something which sounds and operates almost like the original.


Regarding the resistive charging scheme: if that's not something the cars ever had, I don't advocate
for it. But as for the safety aspect if the battery goes open, there is a simple, inexpensive and
admittedly anachronistic prophylactic circuit: place a power-rated zener diode in parallel with the
battery having a breakdown voltage of say 50V. If you can't easily find zener diodes that can handle
the power, then use a "crowbar" circuit with an SCR and a zener diode to bias the gate. In the
event of an over-voltage because of an open battery, the crowbar shorts B+ to ground and blows the
battery fuse and charger fuse.


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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Mon Jan 14, 2019 7:17 am 

Joined: Thu Sep 29, 2016 4:55 pm
Posts: 20
Hard to restore the origninal South Shore MGs when in East Troy case, im sure a couple of the MGs have disappeared over the last 3 decades.

I disagree about authenticity. you gotta do what you need to do to keep the cars running. If you run the car once a year, then i suppose being original is ok. but if you run it all the time, id go for the best maintence solution. and a solid state inverte/converter is probaly the best bet for East troy.

The riding public is not going to care if the car has an MG or a solid state converter. all they care about is does the car run, and can i ride it.


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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Mon Jan 14, 2019 2:38 pm 

Joined: Sun Jul 20, 2008 12:21 am
Posts: 15
Tony, you've got that right! I personally believe
that the equipment should be preserved as best
as possible. That means adhering as much as possible
to the original parts and methods.

You are correct also, in that 99.99999% of the riding public
does not know nor care anything about the details of how it
runs, and why it runs, and what it represents historically.

Especially with the CSS&SB cars, there is always a balance
of these factors to be considered.

Given the fact that these cars are rather complex, keeping
(6) of them on the active roster is a significant challenge.

This situation also provides the opportunity to test
a few different concepts for charging the 32 volt
batteries.


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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Tue Jan 15, 2019 7:44 pm 

Joined: Thu Nov 22, 2007 5:46 am
Posts: 2536
Location: S.F. Bay Area
A South Shore M-G set is a fairly beefish piece of metal, and oriented parallel to the carbody near the outside. It would do a fine job of concealing a digital converter installed behind it or above it.


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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Tue Jan 22, 2019 3:49 pm 

Joined: Sun Jul 20, 2008 12:21 am
Posts: 15
bump


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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Thu Feb 14, 2019 2:46 pm 

Joined: Sun Jul 20, 2008 12:21 am
Posts: 15
bump


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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Fri Feb 15, 2019 11:55 am 

Joined: Mon Nov 26, 2007 2:54 am
Posts: 849
Location: Califoothills / Midwest Prairies / PNW
Since it does not seem to be mentioned in this thread, you might approach a motor shop and ask what it would cost to rewind a motor for 600v operation rather than 1200? I think the result would be less windings on the same motor. I had heard of someone doing this on a much smaller motor in different voltages with good results. I have not heard of volunteers rewinding motors, but perhaps it is possible to do that and save on cost that way.


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 Post subject: Re: 32 volt battery charging circuit
PostPosted: Fri Feb 15, 2019 2:12 pm 
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Joined: Fri Oct 24, 2008 9:05 pm
Posts: 787
Location: MA
If you do ask about convershion there is a motor shop the Shore Line Trolley museume deals with a lot with good results. Unfortunately I can't remember the name of the shop right now.


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