Guardian Hipot Analyzer – 19055

Hipot or dielectric withstand testing instruments are used for conducting electrical safety tests on electrical components and products to make certain they are in compliance with IEC, UL, TUV, CSA, EN and other electrical safety requirements. The Guardian 19055-C not only includes AC/DC/IR tests but also a new measurement technology – Corona Discharge Detection (CDD).
Guardian 19055 Hipot Analyzer

Key Features

  • Datasheet
  • 500VA output rating
  • Hipot: AC 5kV/100mA – DC 6kV/20mA
  • Insulation: 5kVmax – 1MΩ~50GΩ
  • Output Frequency: 50Hz ~ 600HZ
  • Floating output complies with EN50191
  • Corona Discharge Detection (CDD, 19055-C)
  • Flashover Detection
  • Discharge Level Analysis (DLA)
  • Open/Short Check function (OSC)
  • High Frequency Contact Check (HFCC)
  • Ground Fault Interrupt
  • Standard USB, RS-232, & HANDLER Interface
  • Optional GPIB
  • Key Lock when Fail
  • Programmable Voltage and Test Limit
  • CE Mark
  • Supports A190301 8HV Scanning Box
  • 2-Year factory warranty


Chroma’s Guardian 19055 Series Hipot Analyzers are designed for hipot tests and analysis of transformers, motors and other electronic components. The tests of AC/DC/IR can be programmed in AC 5kV/100mA – DC 6kV/20mA with 500VA output rating which complies with the EN50191 requirements. The Guardian 19055-C not only includes AC/DC/IR tests but also a new measurement technology – Corona Discharge Detection (CDD). Corona Discharge Detection and Discharge Level Analysis (DLA) are used to specify the Corona Discharge Start Voltage (CSV), Flashover Start Voltage (FSV) & BreakDown Voltage (BDV).

These functions provide useful data to verify the product’s insulation and increase the reliability of the product during manufacturing.

For Contact Checking during the hipot test, the Guardian 19055 Series is equipped with a High Frequency Contact Check (HFCC) besides the Open Short Check (OSC) function. By conducting the Contact Check during Hipot test, it can increase the test reliability and efficiency significantly. For convenience, the Guardian 19055 has a large LCD screen for operation. In addition, the GFI human protection circuit and Floating safety output prevents electrical hazard to the operator.


Corona Discharge in Transformer

For Transformers: The internal winding of a transformer often endures unstable voltage for long periods when used under normal conditions. Over time, the insulation is affected if the primary side components are in a state of corona discharge. For example, most power transformers reserve an auxiliary coil for other circuits to use in the primary side as the figure shows. When it is used under Vp=750V for a period of time and if the manufacturing process included faulty insulating tape or tubing it would cause a continuous corona discharge. Insulation of primary winding would be compromised and burned out eventually due to the enameled carbonization.

Corona Discharge in Motor

For Motors: As industrial motors or EV motors are used for long hours and under varying environmental conditions such as temperature and humidity, features like high durability and reliability are most critical. Temperature is also one of the key factors to influence insulation. If corona discharge occurs in turn-to-turn and turn-to-ground, it would cause the insulation to deteriorate due to the increase in heat and material qualitative change. Adding Corona Discharge Detection in hipot testing exceeds the quality requirements for insulation by detecting units with poor insulation early thus reducing the defect rate caused by long-term usage. The image shows Corona Discharge in a motor.

DLA Apps

Discharge Level Analysis for high voltage capacitors, safety capacitors, photo couplers and insulation materials:

When gaps or voids in the insulation medium happen in the manufacturing process, different electric fields will be formed and corona discharge will occur when the hipot test is conducted. The medium changes when such usage continue over time and quality issues will appear due to the faulty insulation.


Discharge Level Analysis

DLA Breakdown

The dielectric withstanding voltage of components depends on materials and the manufacturing processes. For improving insulation in components, discharge levels should be defined including Corona discharge, Flashover and Breakdown. The Guardian 19055 is equipped with a Discharge Level Analysis mode (DLA) for defining the programming voltage, time, counts and limits.

The Guardian 19055 Hipot Analyzer provides discharge analysis of three levels. DLA mode will indicate the withstanding voltage depending on the different level limit beginning with Corona Discharge Start Voltage (CSV), Flashover Start Voltage (FSV), and Breakdown Voltage( BDV). R&D and QC personnel are able to improve insulation by discharge data collection and analysis.


Corona Discharge/Flashover (ARC) Detection/Breakdown in Hipot Test

All hipot and dielectric test equipment have the ability to detect a breakdown, and some have the ability to detect flashover (ARC), but only a few have the added ability to detect CORONA DISCHARGE. Although safety agencies have not included any requirement to measure the corona discharge in the safety test requirements, by accurately measuring the leakage current dynamically in very small levels, it is possible to determine if the unit is in one of the following conditions:

Corona Discharge: an electrical discharge brought on by the ionization of a fluid surrounding a conductor, which occurs when the potential gradient (the strength of the electric field) exceeds a certain value, but conditions are insufficient to cause complete electrical breakdown or arcing. Corona discharge may be an early symptom of an impending breakdown.

Flashover: an electrical breakdown of a gas that produces an ongoing plasma discharge, resulting from a current flowing through normally nonconductive media such as air. Vasily V. Petrov, a Russian scientist who discovered it in 1802, first described the phenomenon.

Breakdown: a rapid reduction in the resistance of an electrical insulator that can lead to a spark jumping around or through the insulator. This may be a momentary event (as in an electrostatic discharge), or may lead to a continuous arc discharge if protective devices fail to interrupt the current in a high power circuit.

The graph below shows the association of these three conditions:

DLA Breakdown
Hipot Flashover


Open/Short Check Function (OSC)

All manufacturers have faced problems with errors in test cable connection or shorts. Chroma solves this issue with its patented OSC function.

The open/short check function is used to check if the connection to the DUT is open (bad contact) or a short during the testing process. When an open contact occurs during testing, the test may result in a PASS for a product that may or should have FAILED. If there is a short in the DUT during testing, the instrument may be at risk with the high load current. Checking for opens and shorts during testing ensures efficient testing and protects the equipment.

In most cases the Device Under Test (DUT) will have some capacitance between the Input line and neutral connections with respect to AC Ground. By applying an alternating voltage and measuring the resulting current we can determine the impedance of the DUT based on its normal capacitance. If the connections are open the resulting AC current will be very low compared to the normal connection, and if the DUT is internally shorted the resulting AC Current will be much higher.

OSC - Open Short Check Function


Ground Fault Interrupt (GFI)

Hipot and Dielectric Withstand test equipment can present an electrical shock hazard to the test operator. Test equipment manufacturers have included a GROUND FAULT INTERRUPT (GFI) circuit to help prevent the operator from being electrically shocked. A ground fault exists whenever currents i1 and i2 are not equal, as shown in the figure below.

When the current meter A1 and A2 detects the difference (i2-i1=iH) between the value i1 and actual i2 test current over high, the device cuts the power transiently to safely protect the equipment operator.

GFI - Ground Fault Interupt

Because of the many safety agency standards, we can always be a good source of information and support when you have questions about safety test requirements and issues. For quick support, our applications engineers, and sales and service support people are readily available to help you.

Model Description
Guardian 19055 Hipot Analyzer (AC/DC/IR) – 500VA
Guardian 19055-C Hipot Analyzer (AC/DC/IR/DLA/CDD) – 500VA
A190355 19″ Rack Mount Kit
A190356 GPIB Interface for Model
A190301 (1930A) 8HV Scanning Box [19055x]
A190708 ARC Verification Fixture
10541 Softpanel Kit

User Manuals

Manuals - 19055 Hipot Analyzer

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User Manuals for 19055 Hipot Analyzer. Available documents are: Quick Start Guide Hardware User Manual All files in PDF format. ...

Application Notes

Open Short Check Function of Chroma Safety Analyzers

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