Prostat PFM-711B - Page 18

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Ion Balance Measurement
The PFM-711B can easily be used to check the ion balance voltage (offset voltage) for many kind of
ionizers using the CPM-720B Charge Plate Assembly.
1. Allow the ionizer to be measured to operate at normal speed for a minimum of 30 minutes
prior to measuring balance. Follow the manufacturer’s instructions for normal operations.
2. Mount the CPM-720B Charge Plate Assembly on the PFM-711B Field Meter Case as described
above.
3. Ground the case of the PFM-711B. Note there are two ways to use Prostat devices to ground
the PFM-711B/CPM-720B combination:
a. If the operator is wearing a properly grounded wrist strap and making direct contact
with the metal ground snap mounted on the back of the PFM-711B’s case, the unit will
be sufficiently grounded.
b. Use an auxiliary worksurface common point ground snap:
i. Mount the 10mm male common point ground snap directly to the 10mm
female snap located on the back of the PFM-711B’s case.
ii. Attach the common point ground cord to a previously tested ground point.
4. Select the range you wish to use for balancing the ionizer.
a. Select the V/inch range on the PFM-711B Field Meter and zero (0) the unit, ±2 volts to
ground. This will provide the most precise balance indication and result in ±5 volts
balance.
b. Select the kV/inch range on the PFM-711B Field Meter and zero (0) the unit to ground.
This will provide a good balance indication and result in approximately ±15 volts
balance.
5. Position the sensing surface of the CPM-720B Charge Plate perpendicular to the ionizer’s air
flow, approximately 12 inches from its front air outlet.
a. Hold the instrument combination so that the CPM-720B Charge Plate is in the airflow;
minimize the airflow to the PFM-711B’s meter case.
b. Make sure good contact is made with the PFM-711B’s ground snap.