Ex vintage ROHDE & SCHWARZ professional communications analysis & monitoring equipment.
This premium AC transformer was designed specifically for use with high specification audio or RF electronic equipment, special features are an EMI/RFI shield connection & the toroid transformer is fully enclosed to prevent coupling (in either direction) between this transformer and other sensitive sections within the equipment e. g input circuits or outputs with large fluctuating changes.
The EMI/RFI shield sits between the primary and secondary and, if properly grounded, can act as an RF filter preventing RF present on the mains from getting through to the secondary. The outer metal enclosure looks like Mu metal (dull grey), feels like Mu metal and responds to a permanent magnet (ferrous).

AC Power Transformer (Torodial)
Ex Rohde & Schwarz
Part # 359 2402
Made in Germany
Step-down (100/120/220/240V AC input & 36V/15V AC output windings)
High current (estimated to be approximately 400VA ~ 500VA capable)
INCLUDED ITEMS:
Front panel ON-OFF switch
Hegener Glaser AG EMI Filter integrated with standard IEC socket and AC input voltage switch (VERY nice compact/sealed unit)
All mounting hardware including central bolt/nut, large rubber base washer & base metal plate
Transformer dimensions: 122mm diameter x 58mm high
Weight: 2.8Kg
Paper sticker on the side of the transformer enclosure gives the part number and below this is a little yellow stick
2.5kV
Geproft (Verified)
I believe this indicates the transformer passed a “insulation breakdown voltage” test of at least 2.5Kv – there is certainly no 2.5Kv winding!

COSMETIC CONDITION:
NO damage to any component
NO primary or secondary windings have been cut “short” – most are terminated with female spade connectors and left in place to make it easier when reusing the transformer, in particular the multi input primary windings to the switch.

TESTING:
Removed from fully functioning (but an obsolete purpose in contemporary times) audio signalling & analysis test equipment.
This transformer reminded me instantly of those used in older Rotel audio equipment.
Inside that casing is the toroidal transformer sitting in solid resin – the case and the transformer cannot be parted from each other.
There are NO voltage markings on any winding, it’s all about the sheath colours!

Primary winding is multi-tap to allow for various user AC voltage networks. Currently the switch is set to 240V
The “other side” of the primary winding goes to the very nice, all metal, fully enclosed/sealed EMI Filter/IEC socket/AC input switch – this is the BROWN wire
The secondary has two completely isolated windings, 37V CT & 15.6V CT
All of these high current secondary wires use stranded wire, not solid core.
Yellow – Yellow – Yellow is the 37V Centre Tap winding. All 3 wires have spade connectors fitted and the centre tap is the wire which has a cable tie holding it with a bunch of other wires.
The AC voltage measured is O/C and I also measured this winding when under full load (equipment on) when it drops to 34V CT UNDER LOAD which was measured at approximately 5A
Green – Green – Green is the 15.6V Centre Tap winding. One wire has a spade connector fitted (centre tap) and the other two wires have been cut from the power supply PCB – bare stranded wires.
The AC voltage measured is O/C and again I also measured this winding when under full equipment load, it drops to 14V CT UNDER LOAD which was measured at 10A
That leaves just one wire, Grey. This is not connected to any other winding or the casing – it is the EMI shield connection. Take this to ground, there is no other purpose to this wire.
I have seen, worked with and used many many torodial transformers in my time but this would have to be up there with one of the best – it is an extremely well made, high performance transformer.