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electrical engineering
Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems that use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...
, a dielectric withstand test (also pressure test, high potential test, hipot test, or insulation test) is an electrical safety test performed on a component or product to determine the effectiveness of its insulation. The test may be between mutually insulated sections of a part, or energized parts and ground. The test is a means to qualify a device's ability to operate safely during rated electrical conditions. If the current
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (hydr ...
through a device under test is less than a specified limit at the required test potential and time duration, the device meets the dielectric withstand requirement. A dielectric withstand test may be done as a factory test on new equipment, or may be done on apparatus already in service as a routine maintenance
The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure and supporting utilities in industrial, business, and residential installat ...
test.Paul Gill (2009), ''Electrical Power Equipment Maintenance and Testing'', Second Edition, CRC Press, 1574446568, page 459
Voltage
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...
withstand testing is done with a high-voltage source
A voltage source is a two-terminal (electronics), terminal device which can maintain a fixed voltage. An ideal voltage source can maintain the fixed voltage independent of the load resistance or the output Electric current, current. However, a r ...
and voltage
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...
and current meter
A current meter is an oceanographic device for flow measurement by mechanical, tilt, acoustical or electrical means.
Different reference frames
In physics, one distinguishes different reference frames depending on where the observer is locat ...
s. A single instrument called a "pressure test set" or "hipot tester" is often used to perform this test. It applies the necessary voltages to a device and monitors leakage current
In electronics, leakage is the gradual transfer of electrical energy across a boundary normally viewed as insulating, such as the spontaneous discharge of a charged capacitor, magnetic coupling of a transformer with other components, or flow ...
. The current can trip a fault indicator. The tester has output overload protection. The test voltage may be either direct current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow throug ...
or alternating current
Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in w ...
at power frequency or other frequency, like resonant frequency (30 to 300 Hz determined by load) or VLF (0.01 Hz to 0.1 Hz), when convenient. The maximum voltage is given in the test standard for the particular product. The application rate may also be adjusted to manage leakage currents resulting from inherent capacitive effects of the test object. The duration of the test is dependent on the test requirements of the asset owner but is normally up to 5 minutes. The applied voltage, rate of application and test duration depend on the specification requirements of the equipment. Different test standards apply for consumer electronics
Consumer electronics, also known as home electronics, are electronic devices intended for everyday household use. Consumer electronics include those used for entertainment, Communication, communications, and recreation. Historically, these prod ...
, military electrical devices, high-voltage cable
A high-voltage cable (HV cable), sometimes called a high-tension cable (HT cable), is a cable used for electric power transmission at high voltage. A cable includes a conductor and insulation. Cables are considered to be fully insulated. This mea ...
s, switchgear
In an electric power system, a switchgear is composed of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to ...
and other apparatus.
Typical hipot equipment leakage current trip limit settings range between 0.1 and 20 mACondor Application Note 5/00, pg. 2 and are set by the user according to test object characteristics and rate of voltage application. The objective is to choose a current setting that will not cause the tester to falsely trip during voltage application, while at the same time, selecting a value that minimizes possible damage to the device under test should an inadvertent discharge or breakdown occur.
See also
*Burn-in
Burn-in is the process by which components of a system are exercised before being placed in service (and often, before the system being completely assembled from those components). This testing process will force certain failures to occur under ...
* Dielectric
In electromagnetism, a dielectric (or dielectric medium) is an Insulator (electricity), electrical insulator that can be Polarisability, polarised by an applied electric field. When a dielectric material is placed in an electric field, electric ...
* Dielectric loss
In electrical engineering, dielectric loss quantifies a dielectric material's inherent dissipation of electromagnetic energy (e.g. heat). It can be parameterized in terms of either the loss angle or the corresponding loss tangent . Both refer ...
* Electrical breakdown
In electronics, electrical breakdown or dielectric breakdown is a process that occurs when an electrically insulating material (a dielectric), subjected to a high enough voltage, suddenly becomes a conductor and current flows through it. All ...
* Electrical isolation test
* Impulse generator
Impulse or Impulsive may refer to:
Science
* Impulse (physics), in mechanics, the change of momentum of an object; the integral of a force with respect to time
* Impulse noise (disambiguation)
* Specific impulse, the change in momentum per uni ...
* VLF cable testing
* Wet leakage current test
References
Electrical tests {{engineering-stub