Electrical Stability Tester (EST) Model DWY-2A



Power supply

16V 4.5a (power adapter)

AC Frequency


Rate of voltage rise

150±10V/s, auto boost

Product Description

Electrical stability tester is a portable instrument for measuring the electrical stability (ES) of oil-based drilling fluid. The electric stability of drilling fluid is related to its emulsion stability and wettability. The tester complies with the electrical stability test procedure described in API rp13b-2 Recommended Practice for field testing of oil-based drilling fluid. The instrument is mainly composed of instrument box, test body, electrode, power adapter and glass beaker. Electric stability tester is a sine wave instrument, which is used to measure the relative electric strength of drilling fluid with continuous oil phase in conventional field and laboratory. It is accurate, simple and portable. The influence of the chemical composition and shear history of drilling fluid on the absolute value of ES is very complex. Therefore, it is not advisable to explain the wet state of drilling fluid according to the single measurement of ES. When deciding the treatment plan of drilling fluid, it can only be based on the change trend of ES.


AC power plug, general operation power requirements allowed Power supply: 16V 4.5A (power adapter) Auto calibration instant performance check Large display, easy to read

Type Specification

DWY-2AElectrical Stability Tester (EST)


Working principle

The measurement of electrical stability (ES) is to apply a sinusoidal electrical signal with gradually rising voltage to a pair of parallel plate electrodes immersed in drilling fluid. The resulting current is very weak until it reaches a critical voltage, after which the current intensity rises sharply. This critical voltage, known as the ES value of the oil-based drilling fluid, is defined as the peak voltage measured when the current intensity reaches 61ua, in volts.

Technical Specification

No.Technical Specification
1Power supply16V 4.5a (power adapter)
2measuring range0V~2048V(Peak Value)
3AC Frequency340Hz±2Hz
4Output waveformsine wave
5Rate of voltage rise150±10V/s, auto boost
6breakdown current61uA±5uA
8Working temperature18℃~26℃(64.4°F~78.8°F)
9Electrode test temperature range0℃~93℃(32°F~199.4°F)
10Storage temperature range5℃~50℃(41°F~122°F)
11Automatic cut-off time1min
12Peak voltage displayDigital liquid crystal display
13electrode spacing1.55mm(0.061in)
14Net weight /gross weight3/3.9kg
15Overall dimensions360x260x175(mm)
16Packing size370x290x240(mm)