Transient – ISO 7637

What Is Transient — ISO 7637?

ISO 7637 defines the laboratory generation of transient voltage events that occur on vehicle supply and signal lines, and their application to the component. The standard defines pulse waveforms representing real events such as disconnecting the battery and switching inductive loads.

Purpose of Transient — ISO 7637

The purpose is to show that the component emerges from sudden voltage events in the vehicle's electrical system without damage or loss of function. These events occur routinely in the vehicle; the component must be designed to withstand them.

Which Products Is Transient — ISO 7637 Applied To?

Electronic control units
Lighting and motor drivers
Sensors and actuators
Infotainment and telematics units
Charging and power-conversion modules

In Which Sectors Is Transient — ISO 7637 Used?

AutomotiveElectric VehicleBatteryElectronics

Standards Related to Transient — ISO 7637

ISO 7637electrical transients conducted in vehicles test

Transient — ISO 7637 Conditions

Pulse waveform: Pulse types defined in ISO 7637-2; the set to be applied comes from the specification
Seviye: Severity level from the vehicle manufacturer's specification
Number of repetitions and interval: Defined in the standard for each pulse type
System voltage: 12 V, 24 V or 48 V system — depending on the component

Equipment for Transient — ISO 7637

Transient pulse generator
Coupling/decoupling networks
Oscilloscope and current probes
Load simulator and supply source
Function monitor

Sample Requirements for Transient — ISO 7637

Must be supplied with component wiring harness and load simulator
The system voltage and supply architecture must be stated
The functions to be monitored and the acceptable functional status must be defined
Some pulse types may be destructive; a spare specimen is recommended

Duration of Transient — ISO 7637

It generally takes several days depending on the pulse set and the number of repetitions.

Transient — ISO 7637 Procedure

1The component is connected to the load simulator and the supply source.
2The pulse generator is connected to the line through the coupling network.
3The pulse waveform is verified with an oscilloscope.
4The defined pulse types are applied in sequence, the specified number of times.
5The functional status is recorded for each pulse group.
6Transients generated by the component are also measured (the emission side).
7A full functional check is performed at the end of the test.

Transient — ISO 7637 Acceptance Criteria

The acceptance criterion is that the component remains within the functional-status class defined in the specification. For some pulse types, the absence of permanent damage is considered sufficient, while for others, no degradation of function at all is required.

Evaluation of Results

In the evaluation, a separate functional status is declared for each pulse type; a single 'passed' statement is not sufficient. Oscilloscope recordings of the applied pulse waveform are an integral part of the report.

Transient — ISO 7637 Report

Sample description, serial number and configuration
Applied standard and year of printing
Selected intensity level and basis for the level
Experimental setup and measurement points
Functional checks performed during the experiment
Observations, measurement results and photographs
A statement that the result applies only to the specimen submitted for testing

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

UNECE R10
Vehicle-manufacturer electrical specifications
IATF 16949 product-approval processes

Standard-Based Tests — What Does This Group of Pages Cover?

The section below describes the field that the Transient test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Standard-based tests are test pages whose address comes from a standard number. What the user is looking for is often not the name of the test but the code written in their specification: not "salt spray test" but "ASTM B117", not "drop test" but "IEC 60068-2-31", not "vibration" but "MIL-STD-810 Method 514".

This preference reflects the reality in the field. An engineer sees a code in the specification received from a customer and searches for that code; they do not need to know the name of the test. The code is the identity of the test and distinguishes the different adoptions of the same test by different bodies.

This group addresses the different adoptions of the SAME TEST separately. The same physical phenomenon may be published under different numbers by ISO, ASTM, EN, IEC, DIN and JIS. Even where the numbers are the same (as with ISO 6892-1 and EN ISO 6892-1), specimen preparation, conditions, calculation details and reporting may differ; adoptions may carry national annexes. The code written in the specification therefore governs, and "similar" is not accepted.

Searching at code level meets a different need from searching at scope level. A user searching for "corrosion testing" wants to learn about the field; a user searching for "ASTM B117" has a specification in hand and wants to know the feasibility, duration and price of that test. Two different intents require two different page structures.

The page for a code describes the scope of that code, the test field it belongs to, the product groups in which it is required and how it differs from neighbouring codes. Test conditions, durations and acceptance criteria are NOT CARRIED: these are defined in the copyrighted text of the standard and in the product specification. This boundary is a deliberate choice; a wrong duration or acceptance criterion means directly incorrect work.

Different parts of the same code and different adoptions of the same number are linked between pages. A user searching for IEC 60335 also sees 60335-2-40; a user searching for ISO 6892-1 also sees the EN ISO 6892-1 and DIN EN ISO 6892-1 adoptions. These links are derived from the number of the code rather than written by hand.

The edition year is NOT CARRIED in the library. It is held as "ASTM D638" rather than "ASTM D638-22", because the edition in force changes over time and the address of the page should not age with the edition. If a year is stated in your specification, that edition governs; if not, the most current edition is applied.

Method groups in this field

Searching by code
Direct search for the code written in the specification; it is found in the library with its code, scope title and issuing body.
Searching by scope title
A test whose code is not known is searched by its subject; a search for "salt spray" brings up the related codes.
Series and part relationships
The other parts of the same series are shown, derived from the number of the code.
Adoption relationships
Different bodies' adoptions of the same number are matched; the claim is kept limited to "the same number".
Superseded codes
Withdrawn codes are not held in the library but, when searched for, the user is directed to the counterpart in force.

Commonly confused in this field

Different adoptions of the same number are not identical texts; they may carry national annexes.
The code written in the specification governs; a technically similar code cannot be substituted.
If an edition year is stated, that edition is applied; the most current edition is not automatically accepted.
A code page carries no test conditions or acceptance criteria; these are in the copyrighted text of the standard and in the product specification.
A part code (for example -2-40) may not be sufficient on its own; the general part of the series is applied as well.

Which decisions these results support

Matching the code written in the specification to the correct laboratory scope
Distinguishing between equivalent adoptions
Clarifying the scope and edition at the quotation stage
Finding the current counterpart of withdrawn codes

Related Tests

Frequently Asked Questions About Transient — ISO 7637

What is load dump?

It is a high-energy voltage surge that occurs when the battery connection is disconnected while the alternator is under load. It is one of the most demanding transients that vehicle electronics encounter, and is addressed under ISO 16750-2 and ISO 7637.

Does it also apply to 48 V systems?

Yes, but the pulse levels and the specification to be chosen vary according to the system voltage.