The Voltage Vault McIntosh Antiques

03/09/2026

03/09/2026

Let’s explore a vintage portable current transformer.

GENERAL ELECTRIC CO. U.S.A.

GE was the dominant American manufacturer of electrical measuring equipment in the early power industry. These instruments were commonly used by utilities, testing engineers, and power plants.

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Approximate Age

Based on the design features:
• Bakelite / phenolic terminal plate
• Cast steel cylindrical case
• Bolt-style binding posts
• Multi-ratio selector taps
• Heavy carry handle

This unit was likely manufactured around:

1915 – 1935

These were common in the early expansion of electrical power systems when engineers needed portable test transformers for substations and generators.

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Nameplate Information (from your photos)

The plate reads approximately:

CURRENT TRANSFORMER

Spec: 160136
Type: S Form
Burden: 25 / 125 Watts

Ratios available:
• 5 : 1
• 10 : 1
• 20 : 1
• 30 : 1

Primary Current Rating:
40 Amps

Important warning:

“The secondary must not be open-circuited when the transformer is connected in circuit.”

That warning is critical for CTs.

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What This Device Was Used For

This is a portable current transformer used for electrical measurement and testing.

Its job was to convert high current into a smaller measurable current so instruments could read it safely.

Example:

Power line current = 400 amps

Your CT might convert that to:

5 amps

Then a meter can measure it safely.

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Why Early Engineers Needed These

In the early electrical industry:
• Power lines carried hundreds or thousands of amps
• Meters could only measure a few amps

So engineers used CTs to scale the current down.

Typical uses:

• Substation testing
• Generator output measurement
• Protective relay testing
• Meter calibration
• Field diagnostics

This portable model allowed engineers to carry it from site to site.

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How This CT Works

Inside the steel cylinder are:

1. Iron Core

A laminated steel magnetic core.

2. Secondary Coil

A fine wire coil wrapped around the core.

3. Primary Conductor

The conductor carrying the current passes through or is connected to the heavy terminals.

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The Physics

When current flows through the primary conductor:

It creates a magnetic field.

The magnetic field passes through the iron core and induces current in the secondary winding.

The transformer ratio determines the scale.

Example:

If the ratio is 20:1

Primary current = 100 A

Secondary current =

5 A

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Why the Warning Is Important

The nameplate warning:

Do not open the secondary circuit while energized.

This is because:

When the secondary is open:

The CT tries to maintain current balance.

Voltage across the secondary can rise to thousands of volts.

That could:

• destroy insulation
• shock operators
• damage the CT

This is why CTs are always shorted when disconnected.

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Why There Are Multiple Terminals

Those large studs allow different turn ratios.

Your CT has selectable ratios:

5:1
10:1
20:1
30:1

Engineers would change which terminals they used depending on expected current.

This made one CT usable for many ranges.

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Why It’s So Heavy

Early CTs were built extremely robust:

• thick steel housing
• oil or air insulation
• large laminated cores
• high mechanical strength

They had to survive:
• substations
• power plants
• field testing conditions

Your unit probably weighs:

25–40 pounds

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Why It Has a Carry Handle

Because this was designed for field engineers.

A test engineer could walk into a substation carrying:
• this CT
• a portable ammeter
• test leads

and perform current measurements.

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Historical Context

This was built during the early electrification era.

Around this time:
• cities were building large power stations
• substations were expanding
• utilities were installing protective relays

Companies like:
• General Electric
• Westinghouse Electric Corporation
• Allis‑Chalmers

made thousands of instruments like this.

These tools helped engineers design the modern power grid.

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Why Collectors Love These

Early electrical equipment collectors value these because:

• Industrial design
• Heavy cast construction
• Historical power-engineering artifacts
• Beautiful brass nameplates

Your example is in very good original condition.

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Estimated Collector Value

Depending on condition and collector interest:

Typical range:

$150 – $500

More if sold to:
• electrical museum collectors
• early GE instrument collectors
• power engineering historians

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One More Interesting Detail

The brown rear plate appears to be Bakelite, one of the first synthetic plastics ever used in electrical equipment.

Invented in 1907, it quickly became standard for high-voltage insulation.

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The Coolest Thing About Your Piece

Your CT represents the era when engineers were literally inventing modern power measurement techniques.

Before these instruments existed:

Measuring high electrical current was extremely difficult.

This device helped make modern power grids possible.

02/18/2026

Magnetic inclinometer

02/18/2026

Sticking with magnetism and electrical theory lets venture down this mine shaft.

Early 1900s Industrial Magnetic Inclinometer

Brillisour & McIntyre – Lyons, Illinois
Serial No. 60534

This isn’t a standard compass — it’s a magnetic inclinometer, an industrial instrument used to measure tilt or angle, not direction.

Unlike a surveying compass that measures 360° of bearing, this instrument is graduated from 0° to 90°, meaning it was designed to measure slope or vertical alignment. Zero degrees represents level (horizontal), and ninety degrees represents vertical.

Inside the brass housing is a weighted, magnetized vane mounted on a precision pivot. When the instrument tilts, gravity causes the weighted pointer to swing, and the angle is read directly off the scale through the glass face. There’s no bubble level because gravity itself is the reference point — the instrument simply responds to tilt.

In the early 1900s, tools like this were used in:

• Mining hoist systems
• Elevator and shaft alignment
• Crane and rig angle monitoring
• Industrial machinery setup

During the industrial boom of the late 19th and early 20th centuries, mining and heavy industry demanded reliable mechanical instruments that could withstand harsh environments. Companies like Brillisour & McIntyre manufactured rugged brass devices like this one to provide simple, accurate readings without electricity or delicate components.

It’s a great example of early precision engineering — built to last, purely mechanical, and designed for real-world industrial work.

Over a century later, it still works on the same principle: gravity never goes out of style.

02/13/2026

Open frame DC motor

02/13/2026

Old school open frame DC motor.

This is a vintage open-frame DC electric motor, most likely late 19th to early 20th century (roughly 1890–1925),

1. Commutator and brush assembly (front)
• The copper segmented cylinder is a commutator
• The carbon brushes are held in heavy brass brush holders
• This is definitive evidence of a DC motor or DC generator

2. Field windings
• You can clearly see cloth-insulated copper wire wrapped around iron pole pieces
• The insulation style (cloth/lacquer, not plastic) strongly dates it pre-1930

3. Cast iron yoke (housing)
• Thick, rough-cast iron was common before precision steel stampings
• The “C” shaped magnetic frame is typical of early industrial motors

4. No cooling fan or enclosure
• This is an open-frame motor, designed for clean indoor environments
• Later motors (post-1930s) were usually enclosed for safety and cooling

5. Wooden base
• Early motors were often bench-mounted on wood or slate
• Factories and labs commonly used wood bases before steel frames became standard

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What it does (how it works)

This machine converts direct current (DC) electricity into rotational motion.
1. DC current enters the brushes
2. The commutator switches current direction as the rotor turns
3. Magnetic fields interact between:
• Field coils (stationary)
• Armature windings (rotating)
4. The result is continuous rotation

If driven mechanically instead of electrically, the same machine could act as a DC generator (dynamo).

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Date of manufacture (best estimate)

Based on construction details:
• Cloth insulation (not rubber or PVC)
• Heavy brass brush gear
• Open frame, no safety shielding
• Cast iron magnetic yoke
• Wood mounting base

Likely manufactured between 1895 and 1915, possibly stretching to the early 1920s if used in a lab or specialty application.

This places it squarely in the early electrification era, when electricity was still transitioning from experimental to industrial.

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Typical uses at the time

These motors were workhorses of early electrical systems.

Common applications:
• Laboratory equipment
• Machine shop lathes
• Drill presses
• Fans and blowers
• Printing presses
• Small pumps
• Belt-driven line shaft systems
• Educational demonstrations

Because DC power was dominant before widespread AC standardization, motors like this were everywhere in:
• Factories
• Telephone exchanges
• Power stations
• Universities
• Telegraph offices

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Why it looks so “overbuilt”

Early electrical engineering followed a simple rule:

If you’re not sure, make it heavier.

Reasons:
• Limited understanding of long-term thermal effects
• No finite element magnetic modeling
• Materials were inconsistent
• Failure could mean fire or electrocution

So everything is massive, slow, and durable.

Many of these motors still run today with minimal refurbishment.

02/03/2026

Transformer

02/03/2026

They don’t build them like this anymore.

Wappler Electric Company was an early American electrical instrument manufacturer based in New York City that became known for producing X-ray equipment, electro-medical devices, and later specialized surgical instruments in the late 19th and early 20th centuries. 

🏢 Origins and Timeline
• The company was founded around 1898–1900 in New York, emerging during the early years of electrically powered therapeutic and diagnostic machines. 
• It appears in period catalogs and trade literature through at least the mid-20th century — there are photographs of Wappler’s office building construction around 1953. 

⚙️ What They Built

Wappler Electric was best known for developing and manufacturing electrical medical and diagnostic equipment, including:
• X-ray transformers and accessories — these were key parts of early X-ray imaging setups used in clinics and hospitals. 
• Electrotherapy devices — equipment designed to deliver controlled electrical currents for therapeutic uses (e.g., medical batteries, diathermy handles, electrodes). 
• Electrosurgical and cystoscopic instruments — later in its history, Wappler’s products were used in electrocautery and endoscopy. Notably, physician Edwin Beer used Wappler electrical equipment for early electrosurgical bladder tumor treatments around 1910. 
• It also collaborated with surgeons; for example, its electrical expertise contributed to early laryngoscope designs with Henry Janeway around 1913. 

Artifacts like otoscopes and medical transformers marked with “Wappler Electric Co., N.Y.” and patent dates from the early 20th century survive in museum collections. 

🕰️ Business Duration and Evolution
• Wappler was active from roughly the turn of the 20th century (circa 1898–1900) through at least the mid-1900s, with catalogs and office activity documented into the 1950s and 1960s. 
• Over time the company’s product range evolved from basic electrical and X-ray equipment into more specialized electro-medical and surgical devices — a natural shift as the medical field advanced and as radiology and electrosurgery grew more technical.

📌 Corporate and Legacy Status
• There is no clear record that Wappler Electric Company exists today under that name, and it does not appear to have survived as an active company into the late 20th or 21st centuries under its original identity.
• Like many early medical equipment makers, it likely either ceased operations, was absorbed by another firm, or saw its business diminish as larger medical manufacturers consolidated the market and as technology modernized.
• Its legacy survives primarily in historical collections and archives of early electrical medical devices and in the recorded history of early diagnostic and surgical electro-technology. 

📍 In Summary
• Founded: ~1898–1900 in New York City. 
• Products: X-ray transformers and accessories, electrotherapy devices, surgical electrosurgical equipment, cystoscopic instruments. 
• Period of Activity: Early 1900s through at least the mid-20th century, with evidence of activity into the 1950s. 
• Current Status: Company no longer appears to operate under that name; its products and innovations are documented in historical medical and technological archives.

01/14/2026

Variable Condenser

01/14/2026

A step back in time to the variable condenser. What we call a capacitor this day in age.

What it was used for

Primarily, radio tuning 📻

From roughly 1905 through the 1920s, variable condensers were essential components in:
• Crystal radios
• Early AM broadcast receivers
• Wireless telegraphy equipment
• Laboratory and experimental RF circuits

By adjusting the condenser, the operator could select which radio frequency (station) the circuit responded to.

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How it works (conceptually)

A capacitor stores electrical energy in an electric field between two conductive surfaces separated by an insulator (air, mica, etc.).

A variable condenser lets you change the capacitance mechanically.

Basic principle

Capacitance depends on:
• Plate area
• Plate spacing
• Dielectric material

Early variable condensers changed capacitance by varying how much two sets of plates overlapped.

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Typical early construction

Rotating plate design (most common)
• One set of metal plates is fixed (stator)
• Another set is rotatable (rotor)
• Plates are interleaved but never touch
• Usually air-dielectric (air is the insulator)

Turning the shaft:
• More overlap → higher capacitance
• Less overlap → lower capacitance

No electronics involved — purely mechanical.

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Why this tunes a radio

Early radios used a resonant LC circuit:
• L = Inductor (coil)
• C = Condenser (capacitor)

The resonant frequency is:

f = \frac{1}{2\pi\sqrt{LC}}

So:
• Increase capacitance → lower frequency
• Decrease capacitance → higher frequency

By turning the condenser k**b, you sweep through radio frequencies until one resonates — that’s your station.

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Typical specs (early radios)
• Capacitance range: ~10 pF to 500 pF
• Voltage rating: relatively low (tens to hundreds of volts)
• Often had vernier dials for fine tuning
• Sometimes ganged together (multiple sections on one shaft)

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Other uses (less common but important)
• Antenna tuning
• Transmitters (frequency adjustment)
• Early signal generators
• Scientific instrumentation
• Educational demonstrations

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Why they look so “industrial”

Early variable condensers were:
• Large
• Open-frame
• Made of brass, aluminum, and Bakelite
• Designed to be stable, repairable, and visually inspectable

Nothing was miniaturized yet — reliability mattered more than size.

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Modern equivalent

Today, the same function is done by:
• Tiny variable capacitors
• Varactors (voltage-controlled capacitors)
• Digital frequency synthesis (no moving parts)

But the physics is exactly the same.

01/05/2026

CT DEMO