• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

FT: Transformer, 115/250VAC, 1:1, 30A

Offered for trade is one or two (maybe three) of what I believe to be really nice isolation transformers.

I'm pulling these from 2U rackmount power distribution centers, originally sold by Sun Microsystems in 1995 or 1996 (date code: 9530) as part of a Sun SSA cabinet (holds 144 SCA SCSI-II disks IIRC). I have had these since 1999 or 2000, and they haven't been used at all in that time.

The label on this one reads:

JMK INC
KK-0283-30B
115/250 VAC, KPF
30 AMP, 50/60 Hz
Lc = 1.0 mH
Lg = .56 mH
R = 470 KOHM
Cx = .68 uF (X2)SH
Cy = .0033/.01 uF SH

The schematic diagram shows an RC network on the line side, and caps going from each leg to earth. CSA and Underwriters Unlimited approved, along with another symbol I don't recognize (V, DE in a triangle with 565-3 beside it).

It is enclosed in a sealed metal box, about 3x3x2.75" or so. It will fit inside a 2U rack enclosure in any orientation. It has six lugs, three for load, three for mains, two each of Neutral, Phase 1, and Earth Ground. (N, PH1, and three-pronged rake). When these were inside the enclosure, the earth ground has connected to the chassis, which was in turn connected to the metal box enclosing this unit via the mounting hardware.

Oh, mounting: It has two tapped holes on one side, and four tapped holes on the side with the mains lugs. The screws look like maybe 3/16" UNFs. That's just an eyeball guess. The holes are countersunk to accept flush screws.

Can perform arbitrary [simple] tests before shipping.

Price: I don't want money, I want parts. I'm about to start building an LM3886 chip amp, I could really use a 300VA or better 24Vx2 toroid. I suppose money would do in a pinch (US dollars via Paypal preferred).

Oh, I also have matching power relays, MOVs, and circuit breakers. Note that any of that stuff (circuit breakers?) which care about voltage will be 230V parts. The transformer mentioned above, however, is clearly marked as okay with 115VAC & 60Hz. Sun likes to use 230 inside their cabinets for some reason -- probably to keep the current down in the power cables.

Cheers,
Wes
 
> I simply don't see how you could fit the 40lb+ of iron and copper
> inside less than 3" x 3" x 3'.

Your powers of deduction are obviously better than mine. I was sitting there last night, thinking to myself: "Boy, technology sure has come a long way in the last 30 years. That old 1970s Hammond 1:1 I used to have weighed a ton, and was the size of a cinder block!"

I guess technology can improve, but you can't change the laws of physics. Thanks for the mental tune-up.

(Hey, at least my physical description was accurate! :) )

Wes