Introduction:
The
D.C. Electric Motor drives for industrial applications; nowadays; demand
specification
beyond the requirements generally laid down! This includes; the
operating
hours should be Long and uninterrupted with a minimum of
maintenance
and long working life. The adverse performing conditions capability
with a
product line flexible over a wide range of industrial environment. The
minimum
unquiet environment with motors designed for a low noise level.
Construction
of the Elco D.C. Motors
Frame:
Industrial
applications present a strong necessity for a high degree of mechanical
strength. This implied that the motor frame should be considerably
resistant to deformation and of rugged design. This is a normal practice
with standard Elco industrial motors. The “Elco” D.C. machine is such
designed that the vertical line through the centre of gravity falls between
the
foot
mounting holes in the axial direction resulting in a good weight
distribution to avoid undue loading of the motor feet and possible damage
to the machine in the transport, if it tips.
The
stator frame - Yoke: Solid and Laminated
(a) Fabricated mild steel – Partly
laminated “Elco” D.C. Motors.
(b) Laminated Plates – Fully laminated
‘Elco’ D.C. Motors.
(b.1) made of
fabricated mild steel. The V weld at the meeting
Cornet of the ends of the plate
imparts heavy strength to the
yoke.
(b.2) the yoke is made of special laminations. Thus enabling
Smaller and compact frame; for
a particular horse power;
against the prevalent M.S.
solid yoke D.C.Motors. The frame
is made rigid, thanks to its Special design! The fully
laminated ‘Elco’ D.C. motors are especially suitable for application on
thyristor rectifier supplies (also for four quadrant drives) with a rate of
current rise (di/dt) greater than 200 in/s.
End-Covers:
The end
covers are of cast iron or fabricated which both statically and dynamically
have excellent mechanical properties. The end covers are equipped with long
spigots – At least 2% of the end plates diameter – and small flange width
for fastening to the frame, to avoid misalignment and angular errors.
Foot construction:
The
feet are of substantial steel plate, welded to the frame.
The
terminal box:
The
terminal boxes are made of sheet and manufactured in our well equipped
press tools division, the terminal box may have a higher level of ingress
protection.
Bearing Protection:
In
‘Elco’ D.C. motors, only high quality, medium duty rolling – elements
bearing are used. These are designed to have a fatigue like of at least
50,000 operating hours. Since most present day applications use coupling
drives for the load, the additional radial stressing on the motor shaft is
minimized and ball bearing are incorporated at both the ends in standard
designs. These bearing also have increased radial and axial clearances.
Where heavy pulley drives, overhung gear wheels mounted directly on the
shaft.
Bearing
seals:
Where
possible, the ball bearing are used sealed on one/both, side/s and are
greased for life by the bearing manufacturers.
Bearing
Lubrication:
The
lubricant corrects the functioning of the bearing. Frictional wear and any
abrasion are minimized. Also lubricant serves as anti-corrosive and sealant
element. Proper measure yet should be provided that external element like
dirt, water do not influence the lubricant adversely.
Cooling Provision:
For
self cooled motors, the maximum air fetcher fan is provided which also
reduces the noise generated by the machine.
