Transformer Oil

S.No.

Characteristics

 Value

1.

 Appearance

clear , transparent and free from suspended matter

2.

Density at 29.50C, g/cm3 (Max.)

0.89

3.

Kinematic viscosity at 27 0C, cSt, (Max.)

 27

4.

Interfacial tension  at  270C  , N/m , (Min.)

 0.04

5.

Flash Point , 0C , Pensky Marten(closed ) , (Min)

 140

6.

Pour Point, 0C , (Max.)

 -6

7.

Neutralization value , mg KOH /g

1. Total acidity
2. Inorganic acidity

0.03
Nil

8.

Corrosive Sulphur

Non-corrosive

9.

Break Down Voltage(BDV) , kV (rms) , (Min.)
                              i)       Unfiltered
                              ii)       Filtered

30
60

10.

Dielectric Dissipation factor (tan ) at 900C , (Max)

0.002

11.

Specific Resistance (Resistivity) , ohm-cm

1. at 900C, (Min.)
2. at 270C , (Min.)

35 x 1012 
1500 x 1012 

12.

Oxidation Stability

1. Neutralization value after oxidation, mg KOH /g , (Max.)
2. Total sludge, after Oxidation, % by weight (Max.)

 0.4
 0.1

13

Ageing characteristics after accelerated ageing (open beaker method with copper )

a.

Specific resistance  , ohm-cm

1. At  270C , Max.
2. At  900C , Min.

2.5 x 1012 
0.2 x 1012 

b.

Dielectric dissipation factor (tan ), at 900C, Max.

0.20

c.

Total acidity  mg KOH/gm , Max

0.05

d.

Total sludge , % , Max

0.05

14.

Water content, Max.

50  ppm