Removing shields from bearings depends on the type of bearing shield/seal you have. There are 3 common versions:
• #ZZ / Z → metal shields (non-contact)
• #RS / 2RS → rubber seals (contact)
• Open bearing → no shield

Below is a safe workshop method used for electric #motors, #pumps, #fans, etc.

First — Should you remove them?

Remove shields only if:
• You need to regrease or inspect
• You are converting sealed bearing → open (common on ship motors)
• Bearing is not being replaced anyway

Do not remove if the bearing will stay sealed in dusty/wet environments.

Removing RUBBER seals (RS / 2RS) – easiest

Tools:
• Sewing needle / dental pick / very small flat screwdriver

Steps:
1. Hold the #bearing in your hand.
2. Look at the inner race edge — you will see the rubber lip sitting in a groove.
3. Insert needle between inner race and seal.
4. Gently pry upward.
5. Once the lip pops out → pull the seal off with fingers.

Important:
• Do not stab the rubber.
• Do not bend the metal ring inside the seal.

You can reinstall the #seal later by pressing it back.

Removing METAL #shields (Z / ZZ) – more delicate

Metal shields are thin steel discs crimped into the outer race.

Tools:
• Needle / sharp pick / safety pin
• Good #lighting

Steps:
1. Find the tiny gap between shield edge and outer race.
2. Insert needle into the gap.
3. Twist slightly to lift the shield edge.
4. Move around the circumference slowly.
5. The shield will pop out.

Key rule:
Do NOT bend the shield too much if you want to reuse it.

These shields deform easily.

Cleaning and regreasing (after removal)

Typical motor procedure:
1. Remove old grease:
• Wipe with lint-free cloth.
• Flush with electrical cleaner or kerosene.
2. Spin bearing until fully clean.
3. Dry completely.
4. Fill grease only 30–40% of free space.

#Overgreasing kills bearings faster than undergreasing.

Reinstalling shield/seal
• Rubber seal → press evenly with fingers.
• Metal shield → press gently around edges using socket or flat tube.

Never press on the inner race when installing shields.

💡 Pro marine practice

On electric motors we often:
• Remove one side seal
• Leave the other side sealed
• Install bearing with open side toward grease nipple

This converts bearing into re-greasable type.

#bearings

On February 25, 1896, Nikola Tesla received a patent for an alternating current (AC) #motor—another milestone that helped establish the modern electric power system.

What the AC motor is

An AC motor converts electrical energy from alternating current into mechanical motion. Unlike earlier motors that relied on direct current (#DC), Tesla’s design used a rotating magnetic field to produce smooth and efficient rotation without the need for brushes or complex mechanical commutators.

Why this invention was important

Tesla’s #AC motor became a key component of the new electrical infrastructure that was spreading across the world.

Main advantages
1. Simplicity and reliability
AC motors had fewer moving electrical parts, which meant less maintenance and longer service life.
2. High efficiency
They converted electricity into motion more efficiently, making them ideal for industry and transportation.
3. Perfect match for AC power grids
Since power plants were beginning to generate alternating current, Tesla’s motor could run directly from the grid.

Impact on the world

The #AC motor made it possible to power:
• Factories and industrial machines
• #Pumps, #fans, and #compressors
• Electric trains and transportation systems
• Household appliances

Today, most electric #motors used worldwide are based on the same fundamental principles introduced by Tesla in the 1896 patent.

#NikolaTesla #Tesla

An #incandescent light bulb consists of the following main parts:

1. Glass #bulb (envelope)
A sealed glass shell that protects the inner components and keeps air out.
2. #Filament
A thin wire made of tungsten that glows and produces light when electric current passes through it.
3. Support wires (lead-in wires)
Metal #wires that hold the filament in place and conduct electricity to it.
4. Base (cap)
The metal screw part that connects the bulb to the socket and provides electrical contact.
5. Inert gas or #vacuum
The inside of the bulb is filled with an inert gas (usually argon or nitrogen) or vacuum to prevent the filament from burning.
6. Glass stem / mount
A glass structure that supports the internal #wires and keeps them insulated.
7. Contact tip
The small metal contact at the bottom of the base that completes the electrical circuit.

World power sockets

#socket #sockets

China launches fully electric intelligent container ship with reduced crew

#China has officially put into service the world’s largest fully electric intelligent container ship, marking a major milestone in the decarbonization of coastal shipping.

The #vessel has begun regular operations between the Ningbo‑Zhoushan Port and the city of Jiaxing, supporting short-sea container transport powered entirely by batteries.

A new step toward zero-emission #shipping

The #ship is designed to operate without traditional fossil fuels, relying on large swappable battery modules and high-voltage shore charging. With a capacity of about 740 TEU and a service speed of around 11.5 knots, the vessel demonstrates how #electrification can work on fixed coastal routes.

According to reports from TrasportoEuropa and The Week, the ship is equipped with advanced smart-#navigation technology, including real-time environmental monitoring, route optimization, collision-avoidance systems, and remote-operation capability.

Smaller crew, higher automation

Because the ship has no conventional main engine or fuel systems, automation plays a central role in operations. Industry experts estimate the crew size to be significantly reduced compared with traditional feeder container ships, likely around 6–9 personnel.

The vessel’s fully electric propulsion and high-voltage onboard power systems also highlight the growing importance of electro-technical officers (#ETO) in modern shipping.

Strategic importance for China

The project forms part of China’s broader push to cut emissions in maritime transport and modernize port logistics. The Ningbo-Zhoushan hub, already the world’s busiest port by cargo throughput, is expected to serve as a testing ground for future electric and autonomous #shipping technologies.

Industry analysts view the launch as a pilot project that could accelerate the global transition toward green coastal shipping.

Electric smart container ship sets sail in China

#news

LNG carriers are specialized ships designed to transport liquefied natural gas (LNG) at extremely low temperatures across oceans safely and efficiently. Here’s a clear step-by-step explanation.

1) What LNG actually is

Natural gas is mostly #methane. To ship it economically, it’s cooled to about −162 °C, turning it into a liquid.

Why liquefy it?

Gas shrinks about 600 times in volume
Makes long-distance transport possible by sea instead of pipelines

This process happens at export terminals before loading onto the ship.

2) Cargo tanks — the heart of the ship

LNG carriers look different from normal #tankers because they carry cryogenic tanks instead of oil tanks.

There are two main tank designs:

Moss type (spherical tanks)

Developed by Moss Maritime

- Big aluminum spheres sticking above deck
- Very strong and simple
- Easy to inspect
- Slightly less cargo capacity

Membrane type (prismatic tanks)

Developed by Gaztransport & Technigaz (#GTT)

- Tanks are integrated into the hull
- Thin stainless or Invar membrane supported by insulation
- More cargo capacity
- Most modern LNG carriers use this design

Inside the tanks:

Double insulation layers
Special materials that tolerate cryogenic temperatures
Secondary barrier in case of leakage

3) Boil-off gas — LNG constantly evaporates

Even with insulation, some LNG warms up and turns back into #gas. This is called boil-off gas (#BOG).

Instead of wasting it, ships use it as fuel.

Historically:

Steam turbines burned the gas directly

Modern LNG carriers use:

- Dual-fuel diesel engines (#DFDE)
- ME-GI / X-DF slow-speed engines
- Re-liquefaction plants (on some ships)

Typical boil-off rate: 0.1–0.15% per day

This means the cargo partially powers the ship itself.

4) How loading works

At the export terminal:

- Ship cools cargo tanks gradually (cool-down)
- LNG is pumped via insulated loading arms
- Vapor return line sends gas back to shore to avoid pressure rise
- Tanks are filled while pressure and temperature are monitored

Loading a large LNG carrier (~170,000 m³) takes 12–18 hours.

5) Voyage and cargo management

During the voyage the crew must constantly control:

- Tank pressure
- Temperature
- Boil-off gas production
- Sloshing inside tanks

Key systems onboard:

- Cargo control room
- High-capacity compressors
- Gas combustion unit (#GCU) for emergency gas burning
- Emergency shutdown (#ESD) systems

Safety is extremely strict because LNG is flammable (but not explosive unless mixed with air).

6) Discharging LNG

At the import terminal:

- Ship connects unloading arms
- Cargo pumps push LNG ashore
- Shore terminal warms LNG back into gas (regasification)
- Gas enters national pipeline network

Unloading takes about 10–12 hours.

7) Why LNG carriers are among the safest ships

#LNGshipping has one of the best safety records in maritime history.

#Safety features include:

- Double hull
- Double containment tanks
- Gas detection everywhere
- Emergency shutdown systems
- Separation of cargo and accommodation areas

No major LNG #tanker cargo tank failure has occurred in commercial service.

8) Typical size of LNG carriers

Common sizes:

- 125,000 m³ – older ships
- 170,000 m³ – standard modern LNG carrier
- 210–266,000 m³ – Q-Flex & Q-Max mega carriers

Largest LNG carriers were built for Qatar’s #LNG export projects.

An #LNGcarrier is basically:

- A floating thermos flask
- That burns part of its cargo as #fuel
- And delivers super-cold liquid gas across oceans safely

#MightyShips #ships

Reading milli amps with Process Clamp meter Fluke 772

#Fluke #ProcessClampMeter #ClampMeter

A contactor is an electrically controlled switch used to turn a power circuit ON or OFF. It’s commonly used in #motors, #lighting systems, #HVAC, and industrial machines.

How a contactor works (simple explanation)

A #contactor has two main parts:

Coil (#electromagnet)
Contacts (switching parts)

Working principle step-by-step:

1. No power to coil (OFF state)
The contacts remain open (NO – Normally Open).
No current flows to the load (like a motor or light).
2. Power applied to coil
When voltage is supplied to the coil, it creates a magnetic field.
This magnetic field pulls a movable part called the armature.
3. Contacts close (ON state)
The armature movement closes the contacts.
Now current flows through the circuit to the load.
The device (motor, lamp, etc.) turns ON.
4. Power removed from coil
The magnetic field disappears.
A spring pushes the armature back.
Contacts open again → device turns OFF.

Simple idea:

Small control power (coil) → controls large power #circuit (contacts)

Example:

You press a start button → coil energizes → contact closes → motor runs
You press stop button → coil de-energizes → contact opens → motor stops

Key points:

- Used for high power switching
- Provides safe control using low voltage
- Can be controlled manually or automatically (#PLC, #timers, #sensors)

Turning natural gas (#NG) into liquefied natural gas (LNG) is essentially a massive purification and refrigeration process. The goal is to shrink the #gas so it can be shipped across oceans without pipelines.

By cooling natural gas to -162°C (-260°F), it turns into a liquid and shrinks to 1/600th of its original volume.

This transformation happens at an industrial facility called a liquefaction plant (or an LNG "train"). The process is strict, because if the gas isn't completely pure before it hits the deep freeze, the entire facility will freeze shut.

The #Liquefaction Process

Pre-Treatment (Acid Gas Removal)

*Step 1*

Raw natural gas directly from the ground contains carbon dioxide (CO_2) and hydrogen sulfide (H_2S). These are stripped away using a solvent (typically an amine solution). This is critical because CO_2 freezes into solid dry ice at -78.5°C, which would clog the pipes later.

Dehydration (Water Removal)

*Step 2*

The gas passes through dehydration columns filled with molecular sieves (desiccants) to absorb every trace of water vapor. Just like CO_2, any remaining water would turn to ice and shatter the high-speed machinery.

Heavy Hydrocarbon & Mercury Removal

*Step 3*

Activated carbon #filters absorb mercury, which is highly toxic and can corrode aluminum heat exchangers. The gas is then slightly chilled to separate "heavy" hydrocarbons like butane and propane, leaving nearly pure methane (CH_4).**The Big Chill (Liquefaction)**

*Step 4*

The pure methane enters the main cryogenic heat exchanger. Using giant refrigeration loops (often utilizing mixed refrigerants like nitrogen, ethane, and propane), heat is extracted from the gas until it plummets to -162°C. At this point, it condenses into a clear, colorless, non-toxic liquid.**Storage and #Shipping**

*Step 5*

The LNG is pumped into massive, heavily insulated storage tanks at atmospheric pressure. From there, it is loaded onto specialized double-hulled LNG tankers—essentially giant floating thermoses—to be shipped across the globe.

The Thermos Principle:

LNG #tankers and storage tanks do not have active refrigeration units to keep the gas liquid during transit. Instead, they rely on extreme insulation. A tiny fraction of the liquid naturally warms up and evaporates—this is called "boil-off gas"—and it is typically captured and used to power the ship's engines.

When the ship reaches its destination, the process is reversed at a regasification terminal, where the #LNG is carefully warmed up, turned back into a gas, and fed into local pipeline networks.

Articles about Automatic Voltage Regulator:

1. Automatic Voltage Regulators. What is a generator AVR or Automatic Voltage Regulator?
2. Automatic Voltage Regulator and Parallel Operation of generators. Voltage droop
3. Automatic Voltage Regulator. Real power, Reactive power, Apparent power. KW, KVAR, KVA
4. Function of Voltage Regulator and Parallel Generator Operation
5. The Current Transformer Unit - Parallel Switch. Paralleling Different Size Generators
6. Checking and Troubleshooting a Reactive Compensation Circuit for the AVR in an Isolated AC Bus
7. ACB Trouble. The generator does not connect to the main busbars. Troubleshooting

#alternators #automaticvoltageregulator #AVR #brushlessalternators #generator #generators #powerfactor #regulators #thyristor #voltage #voltagecontrol #voltageregulator