Hipot testers are electrical safety test devices that perform electrical compliance tests. Within the general category of electrical safety testing are a variety of equipment types that are specifically designed to test for electrical compliance. The individual equipment defines the kind of test performed. 

Types of Hipot Testers

Types of measurement performed by hipot testers include AC dielectric strength, DC dielectric strength, arc detection or tracking, insulation resistance, AC/DC selectable, and earth continuity.

• An AC dielectric test measures the withstand capability of an insulator. 
• A DC dielectric test measures the withstand capability of an insulator. 
• Arc detection looks for external break-over during a test cycle. 
• Insulation resistance measures the resistance of an insulator or insulation during a test. 
• Earth continuity devices test electrical and electronic instruments and appliances to make sure they are functioning properly. Electrical instruments that are substandard could fail and transfer dangerous current to their users.

Some test equipment can measure both AC and DC inputs.

Specifications

The most important specifications to consider when searching for hipot testers include AC and DC output voltage, AC and DC output current, resistance range, insulation limit, and test time. Output voltage can either be AC or DC. The type of test will determine what level of voltage will be supplied. For example: in hipot testing, the output voltage is usually very high. Output current can either be AC or DC. The type of test will determine what level of current will be supplied. For example: in hipot testing, the output current is usually very low. Testers can also measure the resistance range. The insulation limit specification determines the voltage range the insulator can withstand. Many tests performed for electrical safety have a test time requirement. This is the overall time of the test.

The testing method for hipot testers can be automatic, semi-automatic, and manual. Some test instruments are fully automated to store and perform testing from a program. They may also have the ability to perform a series of electrical safety tests. Semi-automatic is a combination of automatic and manual testing capability. Manual testing requires that an operator be present to make physical changes to the test parameters.

Features

Displays and interfaces are also important to consider when searching for hipot testers. Display choices include analog meters, digital meters, and LED indicators. Interfaces include GPIB, RS232, printer ports, scanner ports, and printouts. Safety agency ratings that can be applied to hipot testers include CE conformity marks, CSA, IEC, IPC, TÜV Rheinland (US, C, US, and C), UL listing, and VDE. Common features for hipot testers include:

• built-in calibration
• buzzer or annunciator
• front panel lockout
• memory or storage
• multiple test setup
• PLC interface
• rapid cutoff
• remote control
• selectable output frequency
• warning indicator lights

Related Information

CR4 Community—Hipot Value for Medium Voltage Cables

CR4 Community—Insulation Resistance Tester

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Associated Research, Inc.