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The minimum acceptable insulation resistance value is calculated using the following formula:
Rinsulation= (Vrated + 1 ) x (304.8 / L )
Where:
Rinsulation is the minimum acceptable insulation resistance value, in mega-ohms;
Vrated is the rated voltage of the cable (typically printed on the cable), in kilovolts; and
L is the length of the cable, in meters (if the cable length is in feet, replace the number 304.8 with 1000).
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What should be minimum insulation resistance value for 11 kV HT cable?
65 meg ohm if it is 11 kv
What is the acceptable pi value in insulation resistance?
The PI value depends on the type of equipment being tested and the voltage level. Roughly it shall not be below the value of 2.0
What is polarization index?
Polarization Index is an indicator which gives an idea of the cleanliness of the windings. It is a ratio of the Insulation Resistance Measured for 10 minutes to the insulation resistance value measured after 1 minute. Since it is a ratio; it does not have any units.Polarization Ratio = Insulation Resistance after 10 minutes/ Insulation Resistance after 1 minuteThe Polarization Index should be above 2.0 to be permissible. Machines having PI below 2.0 cannot be operated. The Polarization Index does not have any significant relation with temperature upto 50 deg. C. However, the Polarization Index test should not be conducted at a temperature beyond 50 deg. C
How do you measure electrical insulation resistance value?
By Megger testing (meggering) of the motor any one can measure the IR of the motor. MEGGER is a device used to measure IR. Analog Megger device may generate 500 volts..it gives coil to coil or coil to body IR value...it should not be less than 2 Mega ohm, generally it should be or kept more than 5 mega ohm...thanks ...DEEPAK RAJPUT
What is AC cable?
An 'a.c. cable' is an electrical cable designed to work with alternating current, rather than with direct current (d.c.). There are a number of important differences, one of which is the level of insulation necessary. For example an d.c. cable designed to operate at 100 V would not be suitable for operating at 100 V a.c., because all quoted values of a.c. voltage are root mean square (rms) values -which means that a 100 V a.c. cable's insulation must be able to withstand a peak value of around 140 V.
What happens to the value of insulation resistance of a cable when the cable gets older?
Insulation resistance should be approximately one megohm for each 1,000 volts of operating voltage, with a minimum value of one megohm. For example, a motor rated at 2,400 volts should have a minimum insulation resistance of 2.4 megohms.
What should be minimum insulation resistance value for 11 kV HT cable?
65 meg ohm if it is 11 kv
What is the minimum acceptable value of insulation resistance of instrument cable?
more than 1 G ohms is acceptable. cheers
Low resistance on MICC cable how can it be corrected?
by design MICC has a very insulation high resistance. This is measured in Mega Ohms between conductors and between conductors to cable sheath. This high insulation resistance is provided by a highly compressed mineral keeping bare copper conductors apart all within a copper tube called the sheath. Each end of the cable is terminated on site by the engineer to the appropriate length. The termination provides a pot attached the the end of the cable to prevent the ingress of moisture and also a way or providing insulation to the bare conductors. The mineral insulating material in the MICC is quite absorbent so if any moisture is able to get into the cable it will reduce the insulation value of the mineral. Any breach in the integrity of the sheath will allow the cable to breath in moisture and will result in a drop in the insulation value of the cable. The breach can be caused by damage to the sheath by a sharp impact or by age where corrosion to the copper sheath results in a hole. Poorly fitted or damaged terminations can also cause a similar breach and consequent drop in insulation value. As a temporary measure if the damaged section of cable is identified. Isolating the cable from the power supply and providing gentle heat to the outside of the cable with a hand held hair dryer can often improve the insulation resistance value by gently driving out the moisture. It will of course be necessary to replace the damaged section of cable or re assemble the terminations as soon as possible.
Is the R-value of insulation indicate resistance to heat flow?
yes the R-value does indicate resistance to heat flow
The r value of insulation indicate resistance to heat flow?
yes the R-value does indicate resistance to heat flow
Is r-value good or bad?
it is a good thing i think R Value is the thermal resistance of a given material. The higher the R Value the more thermal resistance and the better the insulation. So, an R48 roof system is warmer than an R32 roof system. All insulation materials are rated by their R Value. An inch of rigid insulation has a higher R Value than an inch of fiberglass insulation. Check with the insulation manufacturer for the R Value.
What is R factor in heat insulation?
An R-value is a unit of thermal resistance for a particular material or assembly of materials (such as an insulation panel). The R-value depends on a solid material's resistance to conductive heat transfer.
What is the best type of attic insulation?
Insulation is rated in terms of thermal resistance, called R-value, which indicates the resistance to heat flow. The higher the R-value, the greater the insulating effectiveness. The R-value of thermal insulation depends on the type of material, its thickness, and its density. In calculating the R-value of a multi-layered installation, the R-values of the individual layers are added.
Is the R-value of insulation indicates its resistance of heat flow true or false?
Since you don't want a long explanation ... YES! R-value is an indicator of resistance to heat transmission.
How is insulation measured?
Floors, attics and walls all require insulation of different R-Values which are measured by the thickness of the insulation. The R-Value determines how well the insulation will resist heat flow. The higher the R-Value the more resistance it has to heat and cold. If you are adding to existing insulation there is another factor to consider. You will have to determine the R-Value of the existing to know how much additional insulation to add
What value does 10 insulation give?
If you are referring to the R value of insulation, then 10 would be the 'thermal resistance' value of the insulation. A value of 10 is about what 3 1/2 inches of fiberglass batt insulation would give you. That is what you might put within your exterior walls if you are using wood studs. The higher the R value the better insulation you will have. When you add up all of the R values of the materials that make up your exterior wall you will get your total value. Depending on where your building is located, and the climate in that area, you will need to adjust your insulation accordingly.
