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transformer type/identification ?
By bob g, Section Homebrewed Electricity Posted on Sat Jun 21st, 2008 at 04:03:47 PM MST
is there a reference to transformer type/numbers

seems to me that somewhere in my collection of books/references i have
a chart of cross reference for transformers but i cannot find it.
what i have and am trying to identify is a transformer that has two coils
neither of which are centertapped probably 20lbs in weight
the only number on it is the following
Type
ALT42
no manufacture name or anything else
also is there a general rule of thumb as to approx kva rating per pound of transformer? such as 10 lbs per kva? not looking for specific or exact numbers but
in general.
anyone know or have any answers?
any help would be appreciated
thanks
bob g

transformer type/identification ? | 11 comments (11 topical, 0 editorial)

Re: transformer type/identification ? (3.00 / 0) (#1)
by joestue on Sat Jun 21st, 2008 at 06:10:47 PM MST
(User Info)

Tough one there Bob.

any idea what it is from?
old battery charger?
Arc welder?
isolation tx?

Just plug it in, output at 10% drop is probably full rating.
i would say 2-4Kva.

Re: transformer type/identification ? (3.00 / 0) (#2)
by bob g on Sat Jun 21st, 2008 at 06:41:16 PM MST
(User Info)

not sure what the original application was
but there were three of them banked together.

my thinking is it was some form of 3 phase setup

the primary looks to be approx 13 guage wire
and the secondary looks to be approx 1/8" square copper

the two windings are seperate from each other in a shell configuration
both wound on the center leg of a standard E type core.

nice heavy units, my thinking is maybe 3kva, but might be the
type alt42 might mean 4.2 kva,, but maybe not?

if they are a good 2kva they will work very well for my application i would
think.

don't look to have ever been overheated, copper looks pretty good where it
is visable.

getting very hard around here to find units such as these surplus, so i figured
the 40 bucks i spent for the three was a pretty good deal.

i think i will plug in 120 into the primary and see what i get off the secondary.

guess i will find out one way or another.

thanks

bob g

Re: transformer type/identification ? (3.00 / 0) (#3)
by joestue on Sat Jun 21st, 2008 at 07:47:21 PM MST
(User Info)

I'm sticking with 2 Kva, unless its a 240 volt unit.

/8th inch square is about 4 times the area of a 13 gauge wire.
volt/72 volt? weird voltage.
phase makes even less sense.

[ Parent ]

Re: transformer type/identification ? (3.00 / 0) (#4)
by FuddyDuddy (long.shanks@comcast.net) on Sat Jun 21st, 2008 at 08:27:15 PM MST
(User Info)

Don't know if this helps or not, but I have a set of three transformers. They are 120x240/480v control transformers, rated at 1kva each and weigh in at over 40# apiece !!
Makes yours sound like about a 500va unit, but with a heavy 24v secondary perhaps ?

FuddyDuddy

Re: transformer type/identification ? (3.00 / 0) (#5)
by bob g on Sat Jun 21st, 2008 at 09:57:02 PM MST
(User Info)

i don't think i have ever seen a 40# transformer (dry type) rated at only 1 kva?

i do however have another set of three 120/24 volt units rated at 1.25kva
and they are about 1/3 the size of these transformers i am in reference to.

evidently there is quite a span on these units in size/weight vs kva?

bob g

[ Parent ]

Re: transformer type/identification ? (3.00 / 0) (#8)
by FuddyDuddy (long.shanks@comcast.net) on Sun Jun 22nd, 2008 at 11:13:33 AM MST
(User Info)

These units are about 7" square and 6" high. I suspect the size/weight is due to the fact that the insulation is much thicker than lower voltage units. They are built to run across either a 480vac or 240vac primary and supply 120vac for industrial control systems, thus are quite heavy.

FuddyDuddy

[ Parent ]

Re: transformer type/identification ? (3.00 / 0) (#9)
by bob g on Mon Jun 23rd, 2008 at 07:25:57 PM MST
(User Info)

Fuddy:

well i guess i will have to get around to doing a plug in test and see what it is i have.

also my lift calibration might be significantly off, these might be a bunch heavier than 20 lbs each,, it isn't like i lift stuff daily that i am aware of the weight like i would be if i were a UPS or FEDEX delivery guy :)

i just can't imagine that these would be much less than 2kva each, but we shall see i guess.

i don't really need them to be 2kva, i would be ok with them being 1.5kva each
for my needs and even then they would not be at that load rating for very long.
the majority of the time they would probably be well under 1 kva each.

one just doesn't see these things with enough regularity around here to have a frame of reference.

with scrap prices going to the sky, there will be even less of them laying around.

i got these just hours before they went into the scrap rolloff dumpster for recycling.

bob g

[ Parent ]

Re: transformer type/identification ? (3.00 / 0) (#10)
by FishbonzWV on Tue Jun 24th, 2008 at 04:08:45 PM MST
(User Info)

Bob,

I've got two 3ph xformers, different sizes, with power ratings on them. Both are 208v delta inputs and 32v wye outputs. The coils are as you described, 15 guage wire primary and 1/8" x 1/4" square wire secondary.
I weighed them both to give you some numbers to crunch.
Smaller one is 52 lbs with an output of 65 Amps
Larger one is 77 lbs with an output of 107 Amps.

Hope this helps

Fishbonz

[ Parent ]

Re: transformer type/identification ? (3.00 / 0) (#11)
by bob g on Tue Jun 24th, 2008 at 07:15:22 PM MST
(User Info)

fishbonzwv:

thanks for the info

i need to get a scale, i may be far too light on my estimation
i have been installing and reinstalling a 70lb pto on a truck
for the last 2 weeks (ugly story) and never realized that it was 70lbs
till i looked at the shipping slip today!

so my estimate of 20lbs on these transformers may be off a bit
they might be 30 or 40lbs each,, i dunno :)

my calibration of weight is getting a bit off as i age i guess.

some days 10lbs feels like a hundred, other days who knows
one thing for sure,, a hundred lbs is always too friggin heavy for me
to want to wrangle with.

thanks guys
bob g

[ Parent ]

Re: transformer type/identification ? (3.00 / 0) (#6)
by Simen on Sun Jun 22nd, 2008 at 02:21:45 AM MST
(User Info) http://www.mwlmf.net

Those secondary windings sounds much like the transformer in my 24V, 50A forklift-charger; can't remember the gauge on the primary though. (100-130-210-230-250v inputs...)

Re: transformer type/identification ? (3.00 / 0) (#7)
by GeeMac (foxunc@telus.net) on Sun Jun 22nd, 2008 at 07:08:08 AM MST
(User Info)

I found this for you.

ALT42 1 500KVA used Markon alternator, 415 volt, 3 phase, 50Hz. 0.8pf. 1500 rpm, 2 bearing. (Off 12QT Dorman set). (Our ref Irlam).£1,950.00

So, it might be part of this unit.
GeeMac

transformer type/identification ? | 11 comments (11 topical, 0 editorial)

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