ANSI SP3.3-2016 pdf free download – For the Protection of Electrostatic Discharge Susceptible Items – Periodic Verification of Air Ionizers.
5.0 TEST FIXTURE AND INSTRUMENTATION The following sections describe the instrumentation required for periodic verification of air ionization equipment and systems (ionizers). The test fixture uses an isolated conductive plate for air ion collection. The instrumentation may consist of separate components (high voltage [HV] charging source, voltage monitor, voltage threshold detector and timer), or these components may be integrated into a single instrument. A Charged Plate Monitor (CPM) as described in ANSI/ESD STM3.1 may also be used for periodic and compliance verification. Correlation of the instrumentation used in this document with the CPM defined in STM3.1 is recommended. See Annex B for additional information. The test fixture is to consist of an isolated conductive plate separated from a ground plate on insulating standoff(s). Additional instrumentation is used to charge the isolated conductive plate and monitor the voltage (See Figures 1 and 2). A voltage source that provides a voltage in excess of the initial test voltage of each polarity is required to charge the isolated conductive plate of the test fixture. The voltage source should be current limited so as to meet the requirements of Section 4.0 – Personnel Safety. The voltage on the isolated conductive plate shall be monitored in such a way that, when in the absence of ionization, the isolated conductive plate voltage shall not decay more than 1 0% of the initial test voltage within one minute. The response time of the monitoring device shall be sufficient to accurately measure changing voltages. A timer or other appropriate means should be used to measure the discharge times.
6.0 GENERAL MEASUREMENT PROCEDURE Each ionization application or installation may require a different measurement procedure. Initial and final test voltages should be documented and may be changed if required. The actual measurement procedures and parameters (i.e., equipment, test voltages, test fixture distance and location, air velocity, fan speed settings, compressed gas pressure) should be documented and attached to the test data for use during subsequent periodic verifications. Procedures should be a part of the initial acceptance process to provide baseline data for comparison with future measurements. A schedule should be established for performing periodic verification. The following test steps are common elements to the periodic verification of all types of ionizers.
6.1 Setup Assess the test area after initial ionizer installation. Metal objects or obstructions to airflow are to be noted, but are not to be removed from the test area. The documented test parameters and test results from initial testing will be used for comparison during subsequent periodic verification. The test fixture may be installed within the area to be measured, or it may be held by a grounded test technician. Ground the test fixture per the manufacturer’s instructions.
6.2 Discharge Time The isolated conductive plate shall be momentarily grounded to remove any residual charge and to verify zero of the voltage monitoring device. Charge the isolated conductive plate to a value greater (e.g., ± 1 ,200 to 1 ,500 volts) than the initial test voltage (e.g., ± 1 ,000 volts) and allow it to discharge to the final test voltage (e.g., ± 1 00 volts) while in the presence of ionization. Monitor and record the time required. The discharge time measurement begins when the isolated conductive plate voltage has decayed to the initial test voltage and stops when the isolated conductive plate voltage has decayed to the final test voltage.
A timer or other suitable device should be used for the discharge time measurement. Repeat the discharge time m.ANSI SP3.3 pdf download.