GE Industrial Solutions PowerVac with ML-18 or ML-18H Mechanism - Manual (Page 18)

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design of the interrupter operating rod insulator connection.
They should be returned to the same location from which they
were removed.
11.8—Lubrication
Proper lubrication is important for maintaining reliable circuit
breaker performance. The ML-18 and ML-18H mechanisms
use bearings which have a synthetic lining in some locations.
These bearings do not require lubrication to maintain low
friction, but lubrication does not harm them and oiling lightly is
recommended. Sleeve bearings are used in some linkage
locations and needle or roller bearings are used for low friction
on trip shaft and close shaft.
Bearings are lubricated during factory assembly with grease
and oil, but all lubricants have a tendency to deteriorate with
age. Providing a fresh lubricant supply at periodic intervals is
essential to proper breaker operation, especially where
frequent operation may have forced lubricant out of the
bearing surfaces. Apply a few drops of light synthetic machine
oil such as Mobile 1 at each bearing. Apply a coat of
0282A2048P009 grease on the four corners of the closing
spring guide where it enters inside the spring.
Metal-to-metal contact surfaces should be cleaned and
lubricated with 0282A2048P009 grease to provide cleanliness
and prevent oxidation.
Electrical primary contact surfaces also require periodic
lubrication to inhibit oxidation and minimize friction. At each
inspection and maintenance interval, do the following:
1. Wipe clean and coat lightly with grease
(0282A2048P009) all silvered primary contact surfaces
such as the movable contact rod of the interrupter and
the primary disconnect fingers.
2. Clean and coat lightly with grease the pins of the
secondary disconnect coupler.
11.9—Recommended Maintenance
The following operations should be performed at each
maintenance check:
1. Perform a visual inspection of the breaker. Check for
loose or damaged parts.
2. Perform slow closing operation described under
MECHANICAL CHECKING AND SLOW CLOSING.
3. Check the erosion indicator and the wipe and gap as
described under DIMENSIONAL CHECKS.
4. Perform the vacuum interrupter integrity test as
described under ELECTRICAL CHECKS.
5. Lubricate the breaker operating mechanism as described
under LUBRICATION.
6. Check the electrical operation using the test cabinet (if
available) or the test position in the metalclad switchgear.
CAUTION: REPEATED OPERATIONS AT A RATE EXCEEDING
TWO PER MINUTE MAY CAUSE CHARGING MOTOR
OVERHEATING AND SUBSEQUENT MOTOR FAILURE.
7. Examine the movable contact rod of the vacuum
interrupter. With the breaker open, wipe the lubricant off
the rod and examine the silver surface. The rod should
have a burnished appearance without copper appearing
through the silver. If copper is visible at more than one
location per pole, or if the silver plating is torn, the
interrupter assembly should be replaced. Re-lubricate
movable contact rod with 0282A2048P009 grease
8. If desired, perform the additional electrical tests (Megger,
Primary and Secondary High Potential, and Primary Circuit
Resistance). See ELECTRICAL CHECKS.
Closing coil
current
Tripping coil current
Fuse size close CKT.
Protection Control
Voltage
Source
Closing
range
Tripping
Range
W/O
FBT
With
FBT
5 cycles 3 cycles
Motor
Inrush
current
Motor
Windup
current
W/O
FBT
With
FBT
48 VDC 38-56 28-56 13.7 - 17 17 34 17 30 -
125 VDC 100-140 70-140 6 35.7 5.9 10.5 23 8 20 30
250 VDC 200-280 140-280 2.4 12 4.7 10.8 18 3.8 15 20
120 VAC 104-127 295-360 VDC* 6 - 3.7 3.7 35 15 20 -
240 VAC 208-254 295-360 VDC* 2.4 - 3.7 3.7 20 6 20 30
*Capacitor trip, 120/240 VAC requires the capacitor trip to operate a 340 trip coil.
Table 1. Control Devices and Voltages