Electrical Test & Measurement · Electrical Safety Testers
Programmable safety tester range applying up to 5 kV AC or 6 kV DC, measuring leakage current against preset limits and insulation resistance to 50 GΩ, with arc detection and ten memory groups.
SJ7110 (6 models) ·
A withstand test is a pass or fail judgement, and the instrument that makes it is chosen by the voltage, the current it has to resolve and the way the result is recorded. This series covers that range in six steps, from an AC-only bench instrument to a twelve-kilogram unit with a 50 GΩ insulation range.
All six models apply a programmable high voltage across the item under test and watch the current that flows. What separates them is how far the voltage goes, whether a direct output and an insulation resistance function are fitted, and how the instrument is connected to the line that surrounds it.
The two compact AC-only models exist for one job: an AC withstand test with a leakage limit. From SJ7122 upward a direct output and an insulation resistance function are added, and the two largest models widen the insulation range to 50 GΩ and move to a larger body with a fuller interface set.
The instrument ramps its output to a set voltage over a chosen rise time rather than switching it on instantly. That ramp is what makes the test useful beyond a simple pass or fail: as the voltage climbs, the leakage current is watched, and the point at which it starts to run away locates the weakness instead of merely reporting that one exists.
During the test the measured current is compared with an upper and a lower limit. Exceeding the upper limit means the insulation broke down or the item draws too much leakage; falling below the lower limit usually means the test lead is not connected, which is the failure that a one-sided limit silently passes. Both limits are set independently for that reason.
Arc detection runs alongside the current comparison. A local flashover produces a brief, fast current step that may never lift the total above the upper limit, so a separate detector watches for that signature across a 1 mA to 20 mA window.
The insulation resistance function uses a much lower direct voltage and derives resistance from the current that leaks through the insulation. Because that current is very small, the accuracy is quoted in segments: the higher the resistance, the wider the tolerance.
Three questions settle the choice. The first is the test voltage and the leakage current the applicable product standard requires; that alone decides whether a compact model is enough or whether the 20 mA range of the largest model is needed. The second is whether insulation resistance is part of the test, which rules out the two AC-only models immediately.
The third is the interface. A bench that runs one product all day can use the PLC handshake and a fixture; a line that changes product every hour needs the ten stored groups; and a line controlled by software needs the SCPI command set and the USB or RS232 link.
Body size matters more than it looks. The compact models are 10 kg and fit on a shelf; the two largest are 12 kg with a wider front, which is a different bench footprint and usually comes with a fixture rather than a probe.
The instrument measures the current that flows through the item at a raised voltage, so it says nothing about how the item behaves in service. A product that passes at 5 kV can still fail in the field for reasons the test does not reach, and a test voltage chosen without reference to the product standard proves nothing either way.
The leakage current ranges are small by design. Items that draw tens of milliamps of leakage, such as large motors or long cable runs, need the top of the range, and beyond that the test belongs to a different class of equipment.
Finally, the result is only as good as the fixture. Most production tests are made with a jig that contacts several points in sequence, and the insulation between those contacts is part of the measurement. A test that passes on a bench with a hand-held probe can fail on a fixture whose own leakage is higher than the limit being set.
Every value below is taken from source documentation. Where a parameter is not stated in the available material it is marked as information required rather than estimated.
| AC output voltage | 0.10 kV to 5.00 kV, tolerance ±(2% + 5 V)Standard |
|---|---|
| DC output voltage | 0.10 kV to 6.00 kV, tolerance ±(2% + 5 V); not fitted to the two AC-only modelsStandard |
| AC leakage current range | 0.10 mA to 12.00 mA, tolerance ±(2% + 2 counts); 0.10 mA to 20.00 mA on the largest modelStandard |
| DC leakage current range | 0.10 mA to 5.00 mA, tolerance ±(2% + 2 counts); 0.10 mA to 10.00 mA on the largest modelStandard |
| Lower current limit | 0.00 mA to the top of the current range, set independently of the upper limitStandard |
| Insulation test voltage | 100 V to 1000 V DC, tolerance ±(2% + 5 V)Standard |
| Output frequency | Not stated in the materialInformation required |
| Range, mid models | 1 MΩ to 10 GΩStandard |
|---|---|
| Range, two largest models | 0.1 MΩ to 50.0 GΩStandard |
| Accuracy, 1 MΩ to 1000 MΩ | ±(2% + 2 counts) at 500 V DC or above; ±(5% + 2 counts) below 500 V DCStandard |
| Accuracy, 1000 MΩ to 9999 MΩ | ±(5% + 2 counts) at 500 V DC or above; ±(10% + 2 counts) below 500 V DCStandard |
| Accuracy, largest models | ±5% up to 1 GΩ, ±10% from 1 GΩ to 10 GΩ and ±15% from 10 GΩ to 50 GΩ at 500 V or above; ±10% from 0.1 MΩ to 1 GΩ at 500 V or belowStandard |
| Test time | 0.1 s to 999.9 s, tolerance ±(2% + 0.05 s); 0.2 s to 999.9 s on the two largest modelsStandard |
|---|---|
| Voltage rise time | 0.1 s to 999.9 s, adjustableStandard |
| Voltage fall time | 0.1 s to 999.9 s on the two largest modelsStandard |
| Waiting time before insulation test | 0.2 s to 999.9 s on the two largest modelsStandard |
| Time accuracy | ±(1% + 0.1 s) on the two largest modelsStandard |
| Memory | Ten groups holding voltage, current, resistance and time settingsStandard |
| Discharge after test | Automatic discharge of the direct output when the test endsStandard |
| Display | 16 character by 2 line backlit LCDStandard |
|---|---|
| Indication | PASS and FAIL lamps with a buzzer on failureStandard |
| Remote input and output | Test and reset inputs; pass, fail and test-in-progress outputsStandard |
| Communications | PLC on the compact models; RS232 added on the mid range; HANDLER, RS232, USB device and USB host on the two largest modelsStandard |
| Command set | SCPI, allowing the instrument to be driven without its front panelStandard |
| Operating temperature | 0 °C to 40 °C at 75% relative humidity or lessStandard |
|---|---|
| Body, compact models | 280 × 100 × 370 mm, 10 kgStandard |
| Body, largest models | 425 × 115 × 305 mm, 12 kgStandard |
| Supplied accessory | High-voltage test probe, one per instrumentStandard |
| Ingress protection | Not stated in the materialInformation required |
| Model | Configuration | Key ranges | Availability |
|---|---|---|---|
| SJ7110 | AC only, 0 to 5 kV, 280 × 100 × 370 mm, 10 kg | AC leakage 0 to 12 mA; no DC output and no insulation resistance | For an AC withstand test only |
| SJ7122 | AC and DC, 280 × 100 × 370 mm, 10 kg | AC 0 to 5 kV, DC 0 to 6 kV, AC leakage 0 to 12 mA, DC 0 to 5 mA, insulation 1 MΩ to 10 GΩ | The compact model with the full test set |
| SJ9302 | AC and DC with the two-line backlit display, 280 × 100 × 370 mm, 10 kg | As SJ7122, with insulation resistance quoted in two accuracy segments | For a bench that needs the segmented insulation accuracy |
| SJ9302B | AC only, 280 × 100 × 370 mm, 10 kg | AC leakage 0 to 12 mA; no DC output and no insulation resistance | For an AC withstand test only, with the larger display |
| SJ9310 | AC and DC, 425 × 115 × 305 mm, 12 kg | AC 0 to 5 kV, DC 0 to 6 kV, AC leakage 0 to 12 mA, DC 0 to 5 mA, insulation 0.1 MΩ to 50 GΩ | The larger body adds the wider insulation range and the full interface set |
| SJ9320 | AC and DC with the higher current ranges, 425 × 115 × 305 mm, 12 kg | AC leakage 0 to 20 mA, DC 0 to 10 mA, insulation 0.1 MΩ to 50 GΩ | For items that draw more leakage current, such as large motors and cable runs |
Certifications are only published once a certificate copy can be produced, so this section is deliberately empty rather than populated with assumed approvals. Tell us which approvals your application requires and we will confirm what is available for this instrument.
The following are required for a complete specification but are not stated in the documentation supplied to us. They are listed rather than estimated:
Any model from SJ7122 upward runs both tests, and the two can be chained into one sequence so the item is not handled twice. SJ7110 and SJ9302B are AC withstand only: they have no DC output and no insulation resistance function, so they cannot run the second test at all.
A current limit trips when the total leakage exceeds the set value, which a brief local flashover may never reach. Arc detection looks for the fast current step that a flashover produces in the test loop, over a range of 1 mA to 20 mA, so a fault that is intermittent or localised can still be caught.
The test voltage and leakage current the product standard requires, whether insulation resistance is part of the test, how many test points a single item has, and whether the instrument will be driven from a PLC or from a computer. Those four answers fix the model, the interface and the fixture.
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