|Brief description: || |
The VKA apparatus has also been used for this modified method for more than 20 years. In the KRL test, the balls are replaced by a tapered roller bearing filled with the oil under test. Some 40 ml of the oil under test is subjected to the shear stability test at a temperature of 60 °C and a constant load of 5,000 N with the roller bearing rotating at 1,450 min-1 for a time of 4, 8 or 20 hours in the immersion lubrication method.
The speed of rotation, temperature and load remain constant throughout the test. The decline in relative viscosity at 100 °C for a 4-hour test is stated as the test result in the form: KRL/A: 10.2%.