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 very nice components .... a choke, not just any choke but a monster of a choke!
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
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
HARUNA-DENKI (Japan) - High Current Choke
Made in Japan
Circa late 1990's
Inductance: 10mH
Voltage: up to 250V AC in the original equipment
Current capability: 14A (!)
Part # CH-20403-A
Identification (side printed) markings:
10mH-14A
CH-20403-A
1996-11
HARUNA-DENKI
DIMENSIONS:
Complete choke is 85mm x 85mm x 130mm height
WEIGHT:
3Kg
DESCRIPTION:
Built in metal footing for chassis mounting (4x bolts with a slot fitting)
The core is oval shape and "I think" is a solid Fe nanocrystalline structure. If it uses laminated Fe strips, I cannot see any sign of these laminations when viewed side on, it looks like a solid material similar to a ferrite. Around the outside of the core is a very tight steel band.
Enamelled copper wire is used for the windings and a "guess-timate" of the diameter is 2mm, it is very difficult to get the micrometer inside the core!
On one side of the choke, near the top, are the two screw terminals
The windings and external surface of the windings uses a "plastic like" insulator, NOT PAPER!
COSMETIC CONDITION:
USED (but you wouldn't know it!)
CLEAN (like new!)
No signs of any winding stress at all
Band, laminations (if they are laminations) and windings are all TIGHT and SECURE
TESTING:
Being a previously installed and old component, I took a look at the inductance and resistance
Inductance: 17.8mH
Resistance: 0.8 Ohm
While the L reading is much above that stated on the component (I have no idea what sort of tolerances they built this choke with) being higher than expected is probably a good thing anyway ...
I have now protected this choke with bubble-wrap and sealed it within clear plastic packaging, awaiting installation in that super you-beaut power supply you have always dreamed of creating!
