need a transformer

2 transformers, 18V secondaries, 120V primaries. Primaries in parallel, secondaries in series in phase.

# ----------+ ---+-------)||( | 120VAC | )||( 18VAC | | )||( | -------+---)||( | | | ----+ +----- | | | 36VAC | | # ----+ +----- +-------)||( | | )||( 18VAC | | )||( | +---)||( | ----------+

The transformers in the above example are MPJA #7843 TR

They cost $5.63 each and are rated at 18V 2.0 amps secondary.

The # symbol is for phasing. The secondaries have center taps - don't use them.

Ed

ehsjr Inscribed thus:

Probably no help, but I recall that the old Deskjet 500 printer used a transformer with a 38v AC output at about 2amps. I still use one ! When I get home I'll crawl under the bench and have a look.

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Best Regards:
                Baron.

Junked stereo amplifiers are likely to have higher output transformers.

What do you need it for? That factors in, since it defines how close the voltage has to be, and such.

I once needed 24DC to run a Mac Powerbook, and while digging around to find a suitable transformer, I remembered the inkjet printers I had lying around. I opened one up, and immediately found a switching supply that was easy to extract, and provided 24vdc of suitable amperage. That beat finding a good enough transformer and then building a power supply. But being able to do that depends on what the transformer is needed for.

Michael

How about this one?

36volts CT at 2.8 amps

$8.00 plus shipping

John

baron Inscribed thus:

Sorry I was mistaken ! Its 20v @ 2.4amps. I was sure that I'd seen one rated 38v.

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Best Regards:
                     Baron.

On Jan 20, 3:34=EF=BF=BDpm, Baron wro= te:

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=EF=BF=BD =EF=BF=BD )||( =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD= |

=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD|

| =EF=BF=BD =EF=BF=BD =EF=BF=BD ----+ =EF=BF=BD =EF=BF=BD +-----

| =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD | =EF=BF=BD =EF=BF=BD = =EF=BF=BD =EF=BF=BD =EF=BF=BD 36VAC

| =EF=BF=BD =EF=BF=BD # ----+ =EF=BF=BD =EF=BF=BD +-----

( =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD|

=EF=BF=BD| =EF=BF=BD )||( 18VAC =EF=BF=BD =EF=BF=BD|

=EF=BF=BD| =EF=BF=BD )||( =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD= |

=EF=BF=BD+---)||( =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD|

=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD----------+

ne !

at I'd seen one

=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BDBaron.- Hide quoted text -

This is used in a GBC pouch laminator, they are still being sold new for $2500.00 but GBC has discontinued it and all parts support. If it were the typical cheap 200 buck machine I wouldnt waste my time.

But this is a nice unit in awesome condition. I was told some transformers have thermal fuses buried in the outer windings, so I will do a autopsey tonight.

I am in pittsburgh PA My business is the repair of all brands of roll laminators, including Seal, GBC, Laminex, USI, IDEX, Banner, D&K, and some others.

GBC a ACCO BRANDS company appears in trouble. They cut pay to all employees.

Meanwhile their field service raised their per hour rate from 250 bucks for the first hour to 295 bucks. This includes travel but is way too much for fixing a $1300.00 machine.

I charge a 100 bucks a hour:)

These machines apply plastic to paper think menus. And thanks for the help!

a a

Thermal fuse was blown, it was on the outside of the input winding. Hopefully that will fix the machine. Epoxy will put it back together again.

How sad to toss a transformer for the lack of a fuse:(

Thermal fuse was blown, it was on the outside of the input winding. Hopefully that will fix the machine. Epoxy will put it back together again.

How sad to toss a transformer for the lack of a fuse:(

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Still it is important to determine what might have blown the fuse. Most thermal fuses are rated high enough that when they open, the temperature is high enough to have caused damage to the insulation. It would be prudent to replace it with another thermal fuse. To make sure there is no damage, check the primary current under no-load conditions, and also perform a hipot check between windings. Then operate the unit under normal conditions and check for excess current draw or overheating.

Paul

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Did you replace the fuse?

JF

On Jan 21, 2:16=EF=BF=BDpm, John Fields wro= te:

ing.

yeah had a fuse:) plus i will add a regular fuse too.

the transformer looked brand new, no signs of overheating.

since many machines i repair use thermal fuses I have some observations:)

They do fail as designed when overheated.

When in high current uses they appear to fatigue fail.

Not from overheating but too many thermal cycles.

One manufacturer has this problem, So I put 3 10 amp thermal fuses together in a parrell bundle.

I believe this will end the blown thermal fuse for no reason.

Its irritating and expensive to drive 100 miles just to replace a aged thermal fuse.

since most of my machines are under maintence these trips arent billable and just cost me time and money