3M 718 Instruction Manual - Page 7

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3M 718 Instruction Manual
4.3 Testing ionizer discharge time: after
charging the plate, hold the 718
approximately one foot (30.5 cm)
away from the ionizer. Monitor the
display to see how quickly the 1.1 kV
charge is dissipated to 0.1 kV. The
speed at which this occurs (the
discharge time) indicates how well
the ionizer is operating. Please refer
to the specific ionizer's operating
manual or consult with the ionizer
manufacturer to determine what this
discharge time should be. Repeat this
procedure for both a positively and a
negatively charged plate.
4.4 Testing ionizer offset balance: zero
the charge plate by touching it with a
grounded object. This can either be
the finger of a grounded person or
some other item which is connected
to electrical ground. In either case,
zeroing the charge plate should make
the display on the 718 read zero.
Hold the 718 approximately one foot
(30.5 cm) in front of the ionizer.
Monitor the display. The value
displayed is the offset balance of the
ionizer, which is the difference
between the number of positive and
negative ions being emitted. Please
refer to the specific ionizer's
operating manual or consult with the
ionizer manufacturer to determine
what this offset balance should be.
5.0 Service/Calibration
5.1 Service and Repair: in the event that
you believe the 718 Static Sensor or
the 3M™ 718A Air Ionizer Test Kit
is in need of repair, please contact
your local 3M representative for
troubleshooting help, and, as needed,
repair information. There are no
user-serviceable parts on either
product.
5.2 Calibration: the 718 and 718A
products are supplied by the factory
pre-calibrated. 3M does not specify a
minimum calibration cycle for the
718 or 718A products. The user,
usually according to internal Quality
procedures, determines calibration
cycles. 3M does offer calibration
services on these instruments. Please
contact your local 3M representative
for information on this service. In the
event that the user wishes to perform
a self-calibration, the following steps
should be followed for the 718 Static
Sensor (user-calibration not possible
on the 718A Air Ionizer Test kit).
5.3 Equipment Needed:
Test fixture
High-Voltage Power Supply,
capable of supplying voltages up
to 10,000 V
Voltmeter, with > 50 kΩ input
impedance, capable of measuring
voltages down to the µV range.
Cable with a 3/32 inch (2.5mm)
mono plug and secondary connector
to interface with voltmeter