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Model 4120A DC Dielectric Test Set


DC hipot (over-potential) testing is typically performed when commissioning new installations. It is also used on transformers to verify integrity after a repair.  Additionally, this unit is very well suited for bucket truck (Vehicle-Mounted Aerial Device) testing.  Featuring the latest in pulse width modulation technology, the Model 4120A employs a high frequency power source and feedback circuits to produce a stable, high voltage output with low ripple.

NO MORE lugging heavy wooden boxes to the job site! The 4120A is lightweight and portable.  Analog meters in older designs can be damaged by shock or vibration and can be hard to interpret. The Model 4120A uses digital meters which allow you to precisely set test voltages and easily read test currents.

Available on backorder

SKU: DC 4120A-0 Categories: ,


A front panel feature, unique to the Amblyonix Model 4120A, allows the operator to test Metal Oxide Arresters quickly and accurately. Also provided is a high-voltage DC micro-ammeter used to test leakage currents on the high-voltage side of the insulation testing circuit.


Rated voltage: 120 kVDC
Rated current: 5 mADC
Rated power: 360 W
Weight: 43 lbs.
Power supply: 120 VAC ±10%, 60 Hz
Dimensions: 15.5″ x 22.75″ x 8.5″
Output voltage accuracy: ±(1.0% reading, ±2 digits)
Output current accuracy: ±(1.0% reading, ±2 digits)
Ripple factor: ≤0.5%
Working mode: Intermittent use, 30 minutes under fully rated load
Overload Voltage: The no-load voltage can exceed the rated voltage 10% for 10 minutes.
Overload Current: The maximum charge current is 1.25 times of the rated current.
Operating environment: Temperature 14°F to 104°F
Humidity: To ≤85%RH for temperatures under 77°F, non-condensing


  • Pulse width Modulation (PWM) technology
  • Stable, high-precision voltage adjustment
  • Comprehensive nanosecond threshold protection
  • Unique Metal oxide test function
  • Adjustable overvoltage protection feature
  • Current limiting resistor for capacitive load testing
  • Shielded HV micro-ammeter accessory
  • Shorting rod for grounding output after testing

Supplied with High Voltage Cylinder, Interconnecting Cable, High Voltage Cable, HV Microammeter, Current Limiting Resistor, Ground Cable,
Discharge Rod, Power Cord, Spare Fuse, Line Cord and Manual.

1-year parts and labor warranty.

See the product features video on YouTube here.

Click this link to see: YouTube video of 4120A output being verified.

Additional information

Weight 45 lbs
Dimensions 17 × 24 × 9.5 in