Teikoku DynaPump LE Series, Instruction Manual

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Page 2
1-2. Stator Assembly
The stator assembly consists of a set of three-phase
windings connected in a one-circuit wye arrange-
ment. Stator laminations are of low-silicon grade
steel. Laminations and windings are mounted in-
side the cylindrical stator band. End bells, welded to
the stator band, close off the ends of the stator as-
sembly. The stator liner is, in effect, a cylindrical “can”
placed in the stator bore and welded to the rear end
bell and front end bell to hermetically seal off the
windings from contact with the liquid being pumped.
Terminal leads from the windings are brought into
an oversized electrical terminal box. Motor lead wires
are isolated from the users’ conduit line by a leak-
proof terminal post assembly mounted inside the
terminal box. The design of the stator assembly in
conjunction with the leakproof terminal post assem-
bly provides a true positive secondary containment.
1-3. Rotor Assembly
The rotor assembly is a squirrel cage induction rotor
constructed and machined for use in the Dynapump
LE. It consists of a machined corrosion resistant
hollow shaft, laminated core with cast aluminum bars
and end rings, corrosion resistant end covers, and a
corrosion resistant can. The impeller is keyed to the
shaft and held in place with a bolt and lockwasher.
The rotor end covers are welded to the shaft and
also to the rotor can which surrounds the outside of
the rotor, thus hermetically sealing off the rotor core
from contact with the liquid being pumped.
The shaft is fitted with replaceable shaft sleeves and
thrust collars. These parts are pinned or keyed to
prevent rotation. Axial movement is restricted by the
thrust collars contacting the face of the front and rear
bearings.
1-4. Bearings
The bearings for the Dynapump LE Series are car-
bon graphite as standard (silicon carbide is avail-
able as an option) and are machined with special
helix grooves through the bore to assure adequate
fluid circulation at the journal area. Each bearing is
manufactured to close tolerances for a high degree
of concentricity and is held in a bearing housing by a
retaining screw. Bearings are easily replaced by re-
moving the retaining screw and sliding the bearing
from its housing.
1-5. Thrust Collars and Shaft Sleeves
All Dynapump LE models are equipped with thrust
collars providing a replaceable surface against which
axial loads can be carried during process upset con-
ditions. The shaft is also fitted with replaceable shaft
sleeves. Both the thrust collars and shaft sleeves
are constructed of 316SS with a hard chrome wear
surface for long life. These parts are pinned or keyed
to prevent rotation.
1-6. Cooling Flow
Cooling for stator, rotor, and bearings, as well as
bearing lubrication, is provided by circulation of the
pumped fluid. A portion of the process fluid enters
the motor section through ports in the front bearing
housing. The fluid flows across the front bearing
and returns to the rear of the impeller. The remain-
der passes over the rotor, across the rear bearing,
and returns to suction through the hollow shaft. See
Figure 1-1, Page 1.
1-7. Automatic Thrust Balance
Based on hydraulic principles, Dynapump LE’s au-
tomatic thrust balance is accomplished by the pres-
sure of the pumped fluid itself, operating in a bal-
ance chamber at the front and rear of the impeller.
When a change in load shifts the position of the im-
peller away from the balance condition, there is an
equalizing change of hydraulic pressure in the bal-
ance chamber, which immediately returns the im-
peller-rotor assembly to the balanced position.
1-8. Safety Precautions.
1. Do not run pump dry. If the pump is allowed to
run dry the bearing sleeves and other compo-
nents will be damaged and serious overheating
of the motor windings will occur.
2. Avoid rapid temperature changes. Rapid
changes in temperature can cause leaks to oc-
cur in the gasket areas of the pump.
3. Pump may be hot. Motor section of the pump
can be very hot, even when pumping cool liq-
uids. Motor windings are rated to 356
o
F.
4. If the motor trips due to the thermal cutouts, do
not restart before determining the cause.