Charged plate monitor
The Charged Plate Monitor (CPM) is a measuring instrument that enables a comparison of air ionization devices . Using the field mills - induction -Prinzips are electrostatic potentials and discharge times measured.
The measuring instrument essentially consists of an insulated conductive plate that is charged with a known voltage . The time it takes for the charge to drop to 10% of its value is then measured.
For example, when charging with 1000 V in air with 60% relative humidity, the following elapses until the voltage drops to 100 V:
- without action: 12 hours
- with ionizer under a laminar hood: 10 to 15 seconds
- with ionizer in a clean room: 20 to 60 seconds
- with ionizer in an open space with air conditioning: 50 to 500 seconds
- Ionizer and blower: 5 to 20 seconds
- Ionizer with compressed air ionization attachment: 1 to 2 seconds
Web links
Individual evidence
- ↑ PMT: Special issue on air ionization. Self-published by PMT.