Baldor AC/DC portable generator question

I need a 48 volt DC battery charger setup.

Awhile back, I bought several brand new gensets that were custom made for a telecom company that went bankrupt. Sold for $2000 new (seems high to me).

These generators have 8.5 horse Subaru HD engines, with electric start and setup to run on gasoline or propane.

It appears they were built to charge 36 volt battery banks, but I need to charge 48 volt battery banks.

I called Baldor (or whoever took them over). NO info availalble on this set.

It is supposed to be based on a common Baldor AC genset - model R45. But, it has several large rectifiers added and a Basler voltage-regulator.

The regulator. made by Basler Electric - is marked: Input 180-270 VAC 50-60HZ,
and Output - 63 VDC at 2 amps. It has an adjustable trimmer screw for field output.

When I raise the field current as high as it can go, the generator puts out 50 volts DC. Almost high enough, but not quite. I need 55-56 volts DC.

I'm trying to find out if this generator is already at its max, or can I get it to make 56 volts, by somehow giving it a higher field current?

It is rated, as is, at 62 amps at 36 volts DC and is supposedly built from a 3KW AC genset platform.

JDE,
Now with the little we know, and our local generator guy, we asked him about what you are trying. Now take this with a grain of salt, cause what we know about it , you can put in the corner of your eye and have alot of room left to see.Now, "he" says, that your generator is at it"s max, and the only way to get it to put out more power is to change the head,but you can run a 230V AC genetrator thru a 48 volt inverter to get that amount of juice. This person has a huge business over in Rice Lake,but we have never dealt with him,except to purchase brush assemblies for motors.Will keep looking.Hope some info to help.
Reguards,LOU

Wish I could give you an exact answer JD as youre always so helpful to others, but absent any DETAILED Generator specs IM JUST NOT SURE HOW TO CALCULATE ITS MAXIMUM (its more a mechanical/thermo heat dissipation and insulation problem concerning the fields).

As Im sure youre aware, the more current pumped through its field OR the faster it rotates, the more voltage it can generate. BUT the big limiting factor (which we just dont know) is the max field current the windings can withstand without overheating or degrading the insulation. Of course, the other limiting factor is the current the stator/armature can safely supply.

As far as the regulation, I guess its some sort of pulse width modulation (like when a VR relay chatters) be it solid state or mechanical cycling??? If its solid state it gets complicated to change SCR type of cycling, if its mechanical we may be able to tweak it up. BUT THE BOTOTM LINE REMAINS HOW MUCH CONTINUOUS FIELD CURRENT WILL THE GENSET WITHSTAND. If you full field it she may well produce the desired output BUT WILL THE FIELDS OVERHEAT????

If we increased the field current BEYOND what regulation adjustment you mentioned by say 10% more, my guess is theres enough safety over rating the fields would withstand it.

Think you can get a field current rating when shes set at the max the controller allows??? That may provide some insight but the problem is that may be cycled pulse width modulated in such a manner the ammeter may not give an accurate response.

Maybe this is food for thought, maybe its no use whatsoever, but unless we know the duty/regulation cycle and/or max field current how we gonna figure how much we can increase it so she dont melt down???????

I havent seen my old buddy Dr Gerald Johnson here forever, he still practices engineering and is a whiz on DC Motor/Generator theory, Im sure he could help

Sorry JD

John T

http://www.magniwork.com/?hop=mollymoomo

Is this a load of bunk? or is there something to it? Haven't read the whole artical, came across while looking for a solution to your problem.
Warmest reguards, Lou

jd, try this number 248-852-2055 that is madison electric here in mi. if anyone can answer the question they can. wally

Is bypassing the rectifier and taking the AC out to simple bridge rectifier practical?
How about connecting two generators in series and dialing the excitation down?

I'm just trying to find a use for these gensets and not spend too much money on the deal. They are brand new, and I basically got them for free (long story).

I'm looking for a way to charge my household 48 volt battery bank - just in case I ever have to. I've got solar electric, and in theory - the only time I'd need a charger is if the grid went down for more then two days, and the sun wasn't shining very brightly. I could damaage my expensive Canadian battery bank (Rolls-Surette) if run down too low. We just had a power outage last week that lasted 24 hours, so it got me thinking about this again.

I already have an Iota AC-input 48 volt, 40 amp charger. But, it's only going to work at 1/2 rated capacity on a regular AC genset because of poor quality AC. That's the curse of most AC generators. 20 amps will be pretty useless. It will work at 100% on an inverter generator.

So, I can get an inverter generator just to power my battery charger - and that will work. Probably cost me $400-$500 for a 2000 watt inverter generator. Or, find a way to use this new genset that otherwise, has no use to me. I'd like to find a way to use it. Also nice that it's setup for propane and has electric start, so it can sit forever and I don't have to worry fuel residue going bad in the carb.

Main thing for now is - I can't find any specs on this thing. These generators were actually made by Pow’r Gard in 1999, at $2000 each. Then in year 2000, Baldor bought them out. I called Baldor tech, and they have no records on these units.

I got looking around at univeral voltage regulators and all I've seen so far max out at 63 volts field current with the input I have. I already know that 63 volts at the fields gives me around 51 volts DC output. All I'm shooting for is 56 volts DC, but not sure if it will work, or not.

Perhapes............. the rectifier bank can be supplied with 240V from the generator if, and a big if. If the rectifier bank is currently being supplied with 120V? Then the excitation can be dialed down?

Hey Lou,

In one of the top paragraphs they say they are using Perpetual Motion.

I think that says it all but it can be yours for $49 on sale!

RT