Measuring the breakdown voltage of an insulating oil to IEC 60156 takes a test set that raises the voltage at a controlled rate between standard electrodes, disconnects at the instant of breakdown and computes the statistics of the test series. The OT-90 applies 10 to 90 kV at 2 kV/s with a 3 % measurement accuracy, uses 25 mm radius mushroom-profile electrodes and delivers the mean and standard deviation automatically, for both mineral and synthetic oils.
OT-90 key data
- Test voltage: the OT-90 applies 10 to 90 kV on the electrodes, with a 2 kV/s rise rate and a 3 % voltage measurement accuracy.
- Standard and electrodes: testing to IEC 60156 with 25 mm radius mushroom-profile electrodes, for mineral and synthetic oils.
- Programmable cycle: the test voltage value, rise rate, test time and sample mixing time are programmed; the OT-90 disconnects at the instant of breakdown and repeats the sequence.
- Statistics: it automatically computes the mean of the measurements and the standard deviation, the two figures with which IEC 60156 characterises the dielectric strength of the sample.
- Result logging: built-in thermal printer for the test ticket and a Bluetooth link to a computer that controls the set, stores the results and prints the reports.
- Safety: interlock preventing voltage from being applied with the cover open.
- Power supply: 230 V (50±2 Hz) with 0.5 kW consumption, and an internal battery for up to 8 h of autonomous operation.
- Environment and size: 0 to +35 °C with relative humidity below 80 %; 520 × 335 × 320 mm and 35 kg.
Advantages
Standardised testing up to 90 kV
The voltage on the test electrodes spans 10 to 90 kV with a 2 kV/s rise rate and a 3% measuring accuracy; the mushroom-profile electrodes with a 25 mm radius follow the guidelines of IEC 60156.
Configurable test programme
Test voltage value, voltage rise rate, test time and mixing time are all programmable to match each laboratory procedure, and the instrument automatically calculates the mean of the measurements and the standard deviation.
Results documented on the spot
The built-in thermal printer delivers the test ticket in the field; over Bluetooth, the set is remote-controlled from a computer, which stores the results and prints the reports.
Laboratory-grade safety
A safety interlock prevents power from being applied while the cover is open, and the ergonomic layout supports the correct execution of the test procedure.
Full-day autonomy
The internal battery powers the set for up to 8 hours, so oils can be tested where no mains supply is available.
Applications
- Laboratories of transformer manufacturers and maintenance service companies.
- Oil condition checks on oil circuit breakers, instrument transformers and capacitors.
- Periodic dielectric strength verification in substations.
- Checking oil after filtering or regeneration processes.
About the product
The working cycle automates the complete test: programmed mixing of the sample, voltage rise at 2 kV/s, cut-off at the instant of breakdown and repetition of the measurements until the statistics required by the procedure are complete, with the mean and standard deviation computed without operator input.
The unit measures 520 × 335 × 320 mm, weighs 35 kg and runs from 230 V (50±2 Hz) with a 0.5 kW consumption, operating from 0 to +35 °C at a relative humidity below 80%. Available accessories: test cell with standardised electrodes, temperature probe, Bluetooth adapter and PC remote-control software.
Technical specifications
| Test voltage | 10 to 90 kV |
| Voltage rise rate | 2 kV/s |
| Voltage measurement accuracy | 3% |
| Test standard | IEC 60156 |
| Power supply | 230 V (50±2 Hz); internal battery up to 8 h |
| Power | 0.5 kW |
| Communication and logging | Bluetooth; built-in thermal printer |
| Dimensions and weight | 520 × 335 × 320 mm; 35 kg |
| Test electrodes | Mushroom profile, 25 mm radius, per IEC 60156 |
| Programmable parameters | Test voltage value, rise rate, test time, mixing time |
| Operating conditions | 0 to +35 °C; relative humidity below 80 % |
Frequently asked questions
Which test parameters can be programmed on the OT-90?
On the OT-90 the operator programs the test voltage value, the voltage rise rate, the test time and the sample mixing time. With the IEC 60156 settings, the set raises the voltage at 2 kV/s, disconnects at breakdown, repeats the measurements and computes the mean and standard deviation.
In what conditions can the OT-90 work, and how does it protect the operator?
The OT-90 operates from 0 to +35 °C with relative humidity below 80 %, on 230 V (50±2 Hz) or on its internal battery for up to 8 h. An interlock prevents voltage from being applied while the test cell cover is open.
Why is the oil breakdown voltage tested?
Because dielectric strength reflects the condition of the liquid insulation: moisture and particles lower the breakdown voltage and give early warning of faults in transformers and circuit breakers.
Which standard does the test follow?
The procedure complies with IEC 60156, including the mushroom-profile electrodes with a 25 mm radius recommended by the standard.
How are the results documented?
The built-in thermal printer issues the ticket as soon as the test ends; a computer connected over Bluetooth stores the results and generates the reports.
Can it test synthetic oils?
Yes. The set tests both mineral and synthetic oils with the same standardised procedure.
Does it work without a mains supply?
Yes. The internal battery provides up to 8 hours of autonomous operation, enough for a full day of field testing.
