Digital microhmmeter HZ-3320E-I

portablebench-toplow-resistance

Overview
The HZ-3320E-I handheld transformer DC resistance tester is a portable instrument designed for on-site testing of distribution transformers. It delivers up to 20 A output current and supports one-click three-phase DC resistance and imbalance rate measurements with an algorithm optimized for distribution transformers. The unit is intended for fast, accurate field verification and data collection.

Design & Physical Features
The instrument supports hand-held operation or desktop use with full touch control. The housing is manufactured with secondary injection molding and features rubber pads on four corners for impact protection. The grip area has soft rubber anti-slip texture for secure handling. The front panel is protected by tempered explosion-proof glass over an industrial-grade 7-inch true-color capacitive touch screen suitable for harsh environments.

Product Features

• Maximum test output current: 20 A; selectable gears: 20 A, 10 A, 5 A, 1 A, 0.1 A and low-current mode (≤10 mA).
• Optimized algorithms for distribution transformers enabling one-click three-phase DC resistance and imbalance rate testing.
• Fast test cycle and high measurement accuracy.
• Built-in replaceable lithium battery (16.8 V / 6.4 Ah); optional multiple-battery kits and desktop charger for continuous on-site use.
• Power adapter compatibility across series to prevent incorrect chargers; device operable while charging.
• Supports Yn, Y and Δ winding types with three-phase measurement methods.
• Protection functions including counter-electromotive force (EMF) protection and open-circuit protection.
• Local storage for up to 200 records; supports USB mass storage export; optional external thermal printer.
• User interface: 7" industrial capacitive touch screen, jog dial and buttons for two-handed and desktop operation.
• Single charge typical capacity: test not less than 50 transformers under typical field conditions.

Test Example / Method
Example test sample: dry-type transformer, 1600 kVA, 10/0.4 kV. Example method: test the high-voltage side multiple times at 5 A gear (to simulate different tap positions) and test the low-voltage side once at 20 A gear, adjusting gears according to winding and expected resistance ranges.

Technical Specifications

• Model: HZ-3320E-I
• Type: Three-phase, 20 A
• Output current (gears): 20 A, 10 A, 5 A, 1 A, 0.1 A, ≤10 mA
• Measurement ranges by gear: 20 A: 0.5 mΩ ~ 100 mΩ; 10 A: 1.0 mΩ ~ 300 mΩ; 5 A: 10 mΩ ~ 1.0 Ω; 1 A: 200 mΩ ~ 6.0 Ω; 0.1 A: 2.0 Ω ~ 60 Ω; ≤10 mA: 30 Ω ~ 25 kΩ
• Accuracy: ±(reading × 0.2% + 2)
• Internal power: Built-in lithium battery 16.8 V / 6.4 Ah (replaceable)
• Power adapter (input/output): Input AC 100–240 V, 50/60 Hz; Output DC 24 V / 2 A
• Operating temperature: -10 °C ~ 50 °C
• Relative humidity: ≤90% (non‑condensing)
• Dimensions: 270 mm × 160 mm × 65 mm
• Weight: 2.0 kg
• Data storage: up to 200 records; USB export support
• Display: 7" industrial true-color capacitive touch screen
• Protection & options: EMF and open-circuit protections; optional external thermal printer, additional battery kits, desktop charger