Closed wooden case of an antique German insulation tester, showing the metal latch and age-related wear.

Antique German Hand-Crank Insulation Tester in Wooden Case – No. 327780

€235,00 EUR
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Closed wooden case of an antique German insulation tester, showing the metal latch and age-related wear.
  • Closed wooden case of an antique German insulation tester, showing the metal latch and age-related wear.
  • Antique German insulation tester in its open wooden case, with an analog dial, zero adjustment, and four connection terminals.
  • Close-up of the insulation tester dial with voltage and kilohm scales and German operating markings.
  • Open wooden lid containing a folding metal crank and an original German instruction sheet for the insulation tester.
  • Original German instruction sheet inside the wooden lid, showing connection diagrams and insulation measurement procedures.
  • Detailed view of the curved analog scales, kilohm markings, and aged dial face of the German insulation tester.
  • Side of the wooden insulation tester case, showing dovetail joints, the crank fitting, and a worn leather carrying strap.
  • Closed wooden case of an antique German insulation tester, showing the metal latch and age-related wear.
  • Antique German insulation tester in its open wooden case, with an analog dial, zero adjustment, and four connection terminals.
  • Close-up of the insulation tester dial with voltage and kilohm scales and German operating markings.
  • Open wooden lid containing a folding metal crank and an original German instruction sheet for the insulation tester.
  • Original German instruction sheet inside the wooden lid, showing connection diagrams and insulation measurement procedures.
  • Detailed view of the curved analog scales, kilohm markings, and aged dial face of the German insulation tester.
  • Side of the wooden insulation tester case, showing dovetail joints, the crank fitting, and a worn leather carrying strap.
Antique German Hand-Crank Insulation Tester in Wooden Case – No. 327780

Antique German Hand-Crank Insulation Tester in Wooden Case – No. 327780

€235,00 EUR
This antique German insulation tester is an impressive example of heavy-duty industrial craftsmanship. Believed to date from the early 20th century, it is housed in a beautifully crafted wooden case with traditional, visible dovetail joints and a leather carrying strap. The seller describes the wood as oak. This is not a standard multimeter, but a mechanical hand-crank insulation tester / megohmmeter with a built-in generator or inductor. Turning the folding metal crank on the side was designed to generate the voltage required for insulation measurements. The seller confirms that the crank turns smoothly. Electrical operation, measurement accuracy, and calibration have not been verified. Inside, a deep-black control panel, possibly made of ebonite or Bakelite, features substantial connection terminals and a finely detailed, curved analog dial. German markings, including “Jnstr. 500 k. Ohm” and “Knopf gedr.,” lend the instrument its authentic technical character. The lid contains the original, yellowed paper instruction sheet with connection diagrams and measurement procedures, including “Isolationsmessungen mit Induktor.” A distinctive collectible for enthusiasts of early scientific instruments and authentic industrial design, and a striking display piece for a thoughtfully curated interior. Origin: German, as stated by the seller. Manufacturer: Possibly Hartmann & Braun, Frankfurt. The seller attributes the instrument to this maker based on the serial number and case layout; this identification has not been independently confirmed. Type: Insulation tester / megohmmeter with hand crank and built-in inductor. Serial number: 327780, as supplied by the seller. Date: Believed to be early 20th century, as stated by the seller. Weight: 3937 g. Condition: Noticeable age-related wear to the wooden case, front panel, and metal components, with discoloration of the paper instruction sheet. Please examine the photographs carefully for the visible condition. Only one example of this product is available. Tracked shipping is calculated separately.

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