Electrode Check; Table 6-1. Meter Coil Resistance-Sizes 14 Through 24 Inches - ABB 3000 Series Instruction Manual

3. Connect the ohmmeter test leads to terminal lugs CT and MR. The value displayed
should correspond to that obtained in Step 2 and 1/2 of the value indicated in Table 6-1
within ± 20%.
If proper coil resistance is measured, it can be assumed that the magnet coils are
functional. If the measurement indicates that either or both coils are "open" (infinite
resistance), or shorted (zero resistance), the flowmeter must be replaced.
4. Carefully disconnect the four coil wires from the terminal lugs on the primary pc board.
Identify each wire to ensure proper replacement.
5. Set the ohmmeter to its highest range (R x 10,000) and measure from wire lead M1 or
MR to the meter body (case ground). The resistance reading should be infinite. If this
measurement is less than 100 K ohms, the meter is defective and must be replaced.
When all measurements appear normal, the coil wires can be replaced and the meter can be returned
to service. Replace meter housing cover.

TABLE 6-1. METER COIL RESISTANCE-SIZES 14 THROUGH 24 INCHES

Meter Size
inch
14
16
18
20
24

6.3.2 Electrode Check

The electrode check is essentially a resistance measurement that can be made to establish that a
short (or high resistance leakage path) does not exist between one or both electrodes and the meter
body.
Before proceeding, verify that system power has been de-energized. To perform this test, the meter
must be removed from the pipeline and the meter liner dry. When the meter liner has been thoroughly
dried, proceed as follows:
1. Remove field wiring connected to electrode leads "1" and "2". Proceed to step 2.
2. Place the ohmmeter on the highest available range (for example, R x 10,000).
3. Connect the ohmmeter "minus" lead to the meter ground stud and the "plus" lead to
electrode line 1. This reading should be infinite. If any resistance can be measured, the
meter is defective and must be replaced.
4. Check the other electrode by connecting the ohmmeter "plus" lead to line 2. This
reading must also be infinite. If any resistance can be measured, the meter is defective
and must be replaced.
10DS3111A INSTRUCTION MANUAL
Coil Resistance, M1 to MR
Ohms (nominal)
mm Each Coil
350 10.6
400 9.6
450 9.3
500 9.3
600 9.5
Series (both coils)
21.2
19.2
18.6
18.6
19.0
6-3