Jim,,

While I agree the concept behind a charge plate monitor is not high tech, I
think to get a reliable QA tool you should leave it to the instrument
companies. Ionization current while important in a technical sense in the
design and building of an ionizer in not something that the users of
ionization equipment  typically ask for or measure. Their questions are how
fast (decay times or the ability to reduce charge from 1000V to 100 or
5000V to 500 depending  on application and internal specs ) and how well
(balance or offset voltage). Ionization current is in these numbers but not
directly. Measuring decay time and steady state off set voltage (or
balance) requires some kind of recorder and voltage readout. The typical
EOSESD protocol for testing ionizers is a grid pattern like the work
surface the ionizer is protecting and the typical one number measurement is
18" in front of the unit.

With some components effected by 5V charges an accurate instrument is
required to insure the ionization equipment  is doing more good than harm

More information on static electricity and the use of ionization in ESD is
on our web site http://www.electrostatics.com. Also follow the links  we
offer to the professional societies which have a great deal of information
on ionization. and ESD procedures

Peter Mariani
[log in to unmask]
V 215-513-0850
F 215-513-0855

At 04:22 PM 28-02-98 -0500, Moffitj wrote:
>Mr. Hew How Chee:
>- Measuring ion flux is not a major problem.  Build an ion flux detector as
>follows: Make a "charge plate" out of a piece of alum., brass, copper,
>(anything of that sort).  The plate needs to be about 15cm square (15cm X
>15cm).  Get a piece of screenwire the same size as the charge plate. The
>screenwire should have approximately 3mm to 6mm screen grids and mount the
>screenwire parallel to, but about 6mm to 8mm in front of the charge plate.
>Keep the screenwire and the charge plate electrically isolated from each
>other.  Get a High Voltage DC power supply (3,000 to 4,000 volt range) and
>connect the positive voltage (+3,000 V-dc) to the charge plate.  Connect the
>return (ground) side of the power supply to the screenwire.  Put a
nanoammeter
>( 0 + 20 nanoamp) in the ground wire between the screenwire and the return
>side of the power supply.  Turn the power supply on at about 3,000 volts and
>check to make sure no current is registered on the nanoammeter.  (If any
>current registers you have a high-resistance short or leak in the system
which
>must be eliminated before continuing.)  When no current flows with the power
>supply turned on, move the air ionizer to about 1-meter in front of the
>screenwire/charge plate and turn the ionizer on.   The nanoammeter will
>register a current which indicates the quantity or volume of positive ions
>generated (negative ions will all be attracted to the charge plate).  To see
>if your ionizer is balanced (that is producing the same number of positive
and
>negative ions) just reverse the polarity of the system (+ voltage on the
>screenwire and negative (return side) on the charge plate.
>- Hope this method helps confirm/deny that your ionizer works.

>Regards, Jim Moffitt, Moffitt Enterprises Consulting Service.
>
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Peter Mariani

Ph. 215-513-0850
Fx. 215-513-0855
mailto:[log in to unmask]

Visit http://www.electrostatics.com
to learn more about static electricity

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