HISTORY:
Imported from an international research laboratory (by ship!) as the equipment was being disposed of due to the previous establishment upgrading their equipment in the early 2000's. This is yet another very nice item of industrial equipment which I have decided will become an organ donor.
It is the MATSUNAGA (Yokohama Japan) Frequency Converter, intended for laboratory use and providing up to 240V AC at a user adjustable variable frequency. Not only that, the AC voltage output could be varied across a wide range AND the user could set current limiting, so it could alter all three aspects of the AC output wavefrom, frequency, voltage and current limiting. I actually fired this gear up and it was working great but oh dear! What to do with it? Sure you could put up on the workbench but at that sort of weight it needed a lot of space and a good solid workbench. I decided a while back to offer this equipment as a complete unit "elsewhere" online for a while but there was no interest at all so I pondered over what to do with this equipment (to keep or not to keep) but it had a few things going against it.
As a complete unit it was EXTREMELY HEAVY, over 50Kg, which means that my arms are now 30cm longer from lugging this beast around the workshops! ... but more seriously, shipping would have been difficult to ensure safe travel AND very expensive. It also had other minor cosmetic issues because it is not easy moving such a monster around so it suffered scrap marks on various places of the all steel casing.
So, the "donor operation" has begun and here is one of the transformers from this equipment, low current but "interesting" windings on both the primary and secondary of the transformer.
It is also worthwhile to keep in mind that all of the AC "wound" components (chokes, current transformers, AC step up or down transformers for example) were designed for use across a wide FREQUENCY range, not just 50 ~ 60Hz as the equipment was capable of changing the line output frequency from 40Hz right up to 1Khz
Don't mistake this for your common 240V step down transformer, it is not, but with some lateral thinking and ingenuity this transformer could come in very handy for your special custom project.
The component manufacturer, Haruna-Denki (Tokyo Japan) began operations in 1981 and remain active in the design & manufacture of generator sets, transformers, high power equipment etc
UNIDENTIFIED - AC Power Transformer
I am absolutely 100% sure this is a HARUNA-DENKI (Japan) product
Made in Japan
Physical: E core laminated
Type #: PT-20402A
The transformer ID convention used by the manufacturer is that the secondary ALWAYS has the current rating indicated, the primary only has the source voltage, without a current indication.
Keep in mind that this transformer can be used in either direction but take into account that the current rating does not change and the likelihood of higher turn on "in-rush" currents if used in "reverse"
Primary AC Voltage: 200V - 0V & 200V - 0V
Secondary Voltage: 0V - 100V
Secondary current rating: 150mA
ALL windings are completely isolated, this is NOT an auto-transformer design.
Printed on the outer plastic insulation is the clearly marked winding designations and the part # PT-20402A but no manufacturers name. This transformer "build" looks very similar to the VERY LARGE high current transformer HEREso although this AC transformer is not marked with the makers name, I believe it was manufactured by the same company, HARUNA-DENKI (Japan)
Frame has a standard 2x mounting feet arrangement, no mounting screws/bolts supplied
DIMENSIONS:
53mm height x 62mm width x 49mm deep
Base mounting feet extend the width a further 12mm each side, so the total width including the mounting feet is 86mm
Weight: 600g
COSMETIC CONDITION:
USED (but as new)
NO damage to the laminations or frame
NO damage to the side mounted solder tags, which have been cleaned of previous wiring "dags"
The frame discolouration that can be seen in the photographs is some sort of varnish finish that the manufacturer applied to the frame.
TESTING:
This is what really matters, how does it perform?
Prior to equipment dismantling, this equipment was functioning just fine (see above) but I wanted to take a closer look at this transformer and the possibilies it offered.
First up, a DC resistance test to make sure all windings are ok (since de-soldering) and isolated between each other and a megger test to frame showed infinity. Definitely each winding is isolated from any other winding.
Let's kick this transformer into life and make some voltage measurements ....
I tested this transformer using my trusty high powered GRUNDIG Variac, in the manner this transformer was designed to be used i.e 200V applied to either primary winding. The output at the secondary was 110V NO LOAD. I checked both primary windings separately but did not strap them together for a 400V test, I don't have a convenient source of 400V AC but based on the individual winding tests, all should be fine.
NO surprises in operation, looking great!
