What is insulation resistance tester
Insulation Resistance tester | Megger Explain
Let’s go to understand to my next article that is “Megger”.
Megger is an Electrical instrument. it is measured Electrical leakage in windings, cables, wires or conductors, This instrument enables to passing to follow of electrical current through this instrument
Basically this equipment is indicating the level of insulation of devices like, electrical motor winding, cables, Alternators e.t.c. and it is able to measure the resistance between body to wire, or insulation into wire or cable.
The unit of that instrument is megaohm and denoted by ( Mohm).
The testing equipment under the selectable DC Voltage and suitable of the ship and industrial purpose, Voltage is 250V to 500V to be tested any device.
Types of megger
Basically Two types of megger available in relevant market places
- Hand driven types.
- Battery operated types.
Hand driven types.
Hand driven type or manually driven type megger available in the market, When we are going to test the insulation resistance in hand driven type instrument, showing to test and measured in the figure.
Advantage of hand-operated type megger.
- No need for external sources to perform the operation.
- A better choice for Emergency use.
- Less expensive.
Disadvantage of hand-operated type megger.
- The 2 people need to be operated, one is rotating to the crank and other to connect the leads to be tested on equipment or device
- More time consuming than other types.
Battery operated type.
That type of megger is widely used to measuring devices figure showing.
Advantage of battery operated type megger.
- Accuracy is very high.
- easy to use.
- Easy to see the digital reading.
- Safe to operated.
- Low maintenance cost.
- Better working in congested areas.
Disadvantage of battery-operated type megger.
- Need a source of energy like dry cell or battery.
- Expensive cost.
Parts of battery type megger.
- Digital Display: To show the value of insulation resistance in digit form.
- wire or lead: Basically two leads are required one is connected to the earth and the second one is connected to equipment wire.
- Selector: Selector is the range of selected DC voltage 250v to 500v to perform the test.
- Indicator LED: To show different parameter status like on/off, hold, warning, etc.
Parts of hand-driven type megger.
- Display: An analog meter to display the measuring reading.
- Hand crank: Manually operated hand-driven crank that should be rotated to produce the required DC voltage.
- Wire or leads: Two led are available to test any types of equipment.
Construction of megger.
- Permanent Magnet: Permanent magnet available inside megger to help north and south poles to generate magnet flux or effect of moving the pointer.
- DC generator and battery use: For testing the insulation of any component it is used to perform task, need hand-operated DC generator or battery to be perform the testing.
- Control and Deflecting Coil: There is normally mounted at a 90 degree angle to every other and always connected parallel to the generator.
- Pointer and scale: This is also available to any hand-driven megger to be achieved the actual reading with the help of pointer and scale.
- Pressure coil and current coil: This to be provided to reduce any damage to the megger in case of a very less voltage source.
General maintenance of megger
- Digital Megger is available with inside fuse, if the device is not working then check and replace the fuse.
- it should be cleaned to the dust and grease etc.
- Cleaned the display mirror with the help of a soft cloth.