Download WG3-6-7-11-05-003_Trigger_current_%28ECL%29

WG3-6-7-11-05-003
San Diego 11/5/16
Cover page for contributions to the PC62.36 revision
PC62.36 Clause 8.# ECL Trigger Current Test
Number and Title
Comment
Submitted By
Arnaud Moser
Proposal Summary
Add additional material that deals with the trigger current of
electronically activated devices
Technical Rational
for Proposal
The existing description of the test conditions and procedure are
applicable to thermally-activated devices. Additional material is
needed to deal with electronically activated devices..
Proposed Change
or New Material
WG Resolution
See following pages
Accept/ Reject / Accept with Modifications
8.# Trigger Current Test
8.#.1 Background
Current limiting or interrupting devices all have a transition current rating. In the
case of Electronic Current Limiters (ECL), the transition current is better
described as the trigger current because the change in impedance state is an
instantaneous electronic action rather than a material change of state.
The trigger current is the current which causes the device to transit from a lowimpedance state to a high-impedance state. Generally the time taken to trigger
an ECL is in the order of microseconds. The trigger current of ECL is only
somewhat affected by temperature. Temperature does not affect the time to
trigger.
8.#.2 Purpose
The purpose of this test is to verify the current level required to cause an ECL in
a surge protector to change state at a given ambient temperature.
8.#.3 Equipment
(1) An 80V DC power source capable of delivering 10Amps for 1 second.
(2) A system for displaying and measuring the current through the DUT as
measured by a current probe, as a function of time. Digital equipment is
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suggested, for ease in storing and transferring information. Suitable systems
include digital oscilloscopes, A/D converters, and computer-controlled
multimeters.
The instrument chosen shall have a capability of resolving time intervals from 0.1
microseconds to 1 second.
(3) Current probe with range 0 – 2 amps and response time <1mSecond.
(4) Pulse Capacitor C1 (Ref Figure 8.#-1), 1500uF, maximum voltage > 80V.
(5) Test waveform shaping resistors R1 (8), and R3 (40), (Ref Figure 8.#-1).
These resistors shall have low inductance. Carbon film recommended.
(6) Safety bleed Resistor R2 (1k) (Ref Figure 8.#-1).
8.#.4 Protector States Subject To Test
Unbiased
8.#.5 Procedures
(1) The surge protector, mounted as intended to be used, shall be placed in a
chamber maintained at the specified test temperature. The air flow shall be
controlled to provide a free-convection heat-transfer environment with the
protector shielded from direct flow of forced air. The surge protector shall be
allowed to stabilize at the test temperature.
(2) The specified terminals of the test ECL device shall be connected in series
with the power supply and test circuit as shown in Figure 8.#-1.
(4) When the DUT’s temperature has stabilized, the test switch shall be closed.
The current measurement and recording system shall be configured to record the
trigger of the ECL (where the current reaches a maximum and then quickly
reduced to its normal triggered level (given the specifications of the ECL).
8.#.6 Alternative Methods
None.
8.#.7 Suggested Test Data
(1) Temperature of the chamber in which the DUT is mounted
(2) Source voltage
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(3) Current immediately before the DUT triggers
(4) Current after the DUT triggers
(5) The time required for the transition to occur (from the time of maximum
current to the time of stable minimum current)
8.#.8 Requirement
The DUT shall transition at a current level in accordance with specification. The
DUT shall transition in less than 100us.
8.#.9 Comments
None
ECL = ECL device under test
Figure 8.#-1. Test circuits for the ECL Trigger current test