wholesale high voltage capacitance and dissipation factor tester supplier: Specification, Ordering and Quality Notes
Design Constraints Behind the Specification
When a utility testing lab extends an existing range of diagnostic tools, the first constraint is always the test voltage ceiling. A 12 kV unit cannot characterise 132 kV cable systems, and a 100 kV unit adds unnecessary weight, clearance requirements and cost for distribution-class work. The bridge architecture — whether Schering, Wagner or digital correlation — dictates the lower limit on dissipation factor resolution; analogue bridges typically bottom out around 10-4 while DSP-based correlators reach 10-6 but demand cleaner power and stricter EMI shielding.
Moving from sample orders to container loads changes the thermal design priority. A bench-top demonstrator runs 15-minute tests with 45-minute cool-down; a production-line unit cycling 8 hours daily needs forced-air or liquid-cooled HV transformers, otherwise the dissipation factor drift exceeds 0.5% per hour as winding temperature climbs. That drift is the single largest source of warranty claims in the first 18 months.
Where This Product Beats Standard Alternatives
Analogue Schering Bridge (Legacy)
- No firmware, minimal obsolescence risk
- Tan δ resolution limited to ~1×10-4
- Manual null balance — operator skill dependent
- Typical weight 45–60 kg for 12 kV class
DSP Correlation Tester (This Range)
- Tan δ resolution to 1×10-6 with auto-ranging
- Automated frequency sweep 15–400 Hz for PD correlation
- Built-in temperature correction to IEC 60060 algorithms
- 19" rackmount 22–28 kg for 12 kV; 35–42 kg for 100 kV
The weight saving on the 100 kV model comes from ferrite-cored HV transformers instead of laminated silicon steel — a 30% mass reduction that cuts freight cost per container by roughly 18%. The trade-off is a 15% higher unit BOM, recovered after the second shipment for most distributors.
Size, Weight and Specification Range
| Model Series | Test Voltage (kV RMS) | Capacitance Range | Tan δ Range / Resolution | Dimensions (W×D×H, mm) | Weight (kg) | Cooling |
|---|---|---|---|---|---|---|
| CST-12 | 0.5–12 | 1 pF – 1 µF | 0–50% / 1×10-6 | 483×420×177 (4U) | 22 | Forced air |
| CST-50 | 2–50 | 1 pF – 2 µF | 0–50% / 1×10-6 | 483×520×266 (6U) | 35 | Forced air |
| CST-100 | 5–100 | 0.5 pF – 5 µF | 0–100% / 5×10-6 | 550×650×450 (trolley) | 42 | Liquid loop |
All models include 7" capacitive touchscreen, USB/Ethernet/GPIB, and internal storage for 10,000 test records with CSV export. The CST-100 trolley integrates a 5 m HV cable reel; shorter reels are optional on CST-12/50.
Buying Mistakes That Lead to Returns
Specification Callout
Ordering a 12 kV unit for 11 kV cable testing ignores the IEEE 400 recommendation to test at 1.5–2× rated phase-to-ground voltage. A 12 kV tester only delivers ~6.9 kV phase-to-ground — insufficient for withstand verification on 11 kV systems. Minimum viable model: CST-50.
The second return driver is connector incompatibility. North American utilities expect Type-N or SHV on the HV lead; European specs call for 4 mm banana or proprietary bayonet. We ship with the buyer's specified connector set — but if the PO omits this, the default is SHV, and the rework lead time is 10 working days.
Third: skipping the temperature-correction licence. The firmware ships with basic correction disabled; the licence key unlocks the IEC 60060-1 Annex B algorithm. Without it, tan δ readings on oil-paper insulation drift 8–12% between 15 °C and 35 °C — enough to trigger false "deterioration" alarms on transformer bushings.
What Can Be Customised and What Cannot
| Parameter | Customisable | Constraints / Lead-time Impact |
|---|---|---|
| HV connector type | Yes | SHV, Type-N, 4 mm, M8 stud, custom bayonet — no lead-time adder if specified at PO |
| HV cable length | Yes | 3 m, 5 m (std), 10 m, 15 m — >10 m adds 5 kg and 3 days |
| Chassis colour / silk-screen | Yes | RAL code + logo vector file — 7 days for powder coat cure |
| Test voltage max | No | Fixed by HV transformer winding and clearance; changing requires new safety file |
| Measurement architecture | No | DSP correlation only; Schering bridge not offered on new builds |
| Language pack | Yes | EN, DE, FR, ES, CN, JP, KR, PT, RU — loaded at final test, no adder |
| Calibration certificate format | Yes | ISO 17025 / factory / customer template — template approval adds 2 days |
OEM and ODM Programme Structure
OEM (private label) starts at 15 units per release. We apply your silk-screen, pack in your branded carton, and load the firmware with your boot splash and default language. The calibration certificate bears your part number and our ISO 17025 lab code — traceability stays with us, liability stays with you. Unit price drops 7% at 15, 12% at 50, 18% at 100.
ODM (modified hardware) requires a technical review gate. Typical requests: integrated partial discharge coupler (adds 3 kg, 15 mm depth), dual-voltage output stage (12/50 kV switchable), or battery-backed operation for substation work without mains. NRE starts at USD 28,000 and 14 weeks to first article; minimum annual volume 30 units to amortise. We do not ODM the DSP core — the measurement IP is locked.
How Consistency Is Held Across Batches
Every HV transformer winding undergoes automated turns-ratio and partial discharge mapping at 1.2× rated voltage before potting. The potting cycle — vacuum degas, epoxy fill, 90 °C cure — is logged per serial number; any unit exceeding 5 mbar pressure rise during degas is scrapped. This eliminates the void-induced breakdowns that caused the 2021 field recall on a competitor's 50 kV line.
DSP boards receive a 48-hour burn-in at 50 °C ambient with continuous 1 kV test signal injection. Tan δ drift is recorded every 30 minutes; boards exceeding 2×10-5 drift over the window are rejected. The surviving population shows <5×10-6 drift per °C in production calibration.
Final calibration uses a three-point reference: 100 pF / 0.1% tan δ, 10 nF / 1% tan δ, 500 nF / 10% tan δ — all traceable to NMI primary standards. The certificate ships in the box; digital copy is emailed at dispatch. Batch statistical process control charts are available on request for volumes above 20 units per quarter.
Questions Buyers Ask Before Ordering
Can the CST-12 be upgraded to CST-50 later? No. The HV transformer, clearance spacing and cooling capacity are chassis-integral. Trade-in credit is 35% of list price within 24 months.
What is the calibration interval and cost? 12 months recommended. Our lab charges USD 420 including return freight in-region; third-party ISO 17025 labs typically quote USD 600–900. The firmware logs last-cal date and flags at 11 months.
Does the tester measure capacitance while energised? Yes — the DSP correlation method measures C and tan δ simultaneously on live test objects up to the rated voltage. No external standard capacitor needed.
Export packaging for sea freight? Standard: ISPM-15 plywood crate, foam-in-place corners, desiccant sachets, tilt/shock indicators. Gross weight per crate: CST-12 38 kg, CST-50 55 kg, CST-100 78 kg. Stacking limit two high.
Lead time for a 20-unit mixed order? 6 weeks ex-works if all units share connector spec and language pack. Mixed connectors add 5 working days. OEM silk-screen adds 7 days. We hold safety stock of CST-12 and CST-50 chassis — 5 units each — for express 10-day dispatch.
Request a Calibration Sample or Formal Quotation
We ship evaluation units to qualified distributors and OEMs with a 30-day return option — freight each way on us. Calibration certificates and batch SPC data accompany every sample.
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