FIELD OF THE INVENTION
The present invention relates to an improved ventilating spacer device for
forming air ducts in stator core of hydrogenerators.
BACKGROUND OF THE INVENTION
The ventilating spacers are provided to produce air ducts in stator cores of
hydrogenerator which allow air flow in the stator for cooling of the core including
the winding. These ducts are provided at regular intervals throughout the axial
length of the core which extends from inner diameter to outer diameter of the
stator.
In prior art, the ventilating spacers are spot-welded onto the spacer punching.
The spacer punchings are made in segments, and completes full circle by laying
a plurality number of the segments. The ventilating spacers provided to make
the air ducts, according to prior art cause a high hydraulic loss in the ducts
particularly at the entry to the inner diameter. The direction of air flow gets
reversed in some prior art air ducts, and the quantity of air flow is found to be
inadequate. The arrangement of ventilating spacers in prior art is shown in
figures :-1(A), 1(B), 1(C) & 1(D). The existing arrangement of spacers for
making air ducts has following disadvantages:-
1. Fan has to be selected for higher air flow and pressure, which
consumes more power.
2. The flow in some of the ducts develop reverse direction of flow
resulting in higher temperature of the core and winding. The reverse
direction of flow is shown in figure 2.
3. The churning loss is higher which reduces efficiency of the
hydrogenerator.
4. The material consumption is more due to additional bends and
ventilating spacers.
The higher capacity fans are required in the prior art to deliver the required flow
because of higher churning and hydraulic losses. The higher capacity fans
consume more power. The higher capacity fans, churning loss, hydraulic loss and
temperature lead to lower efficiency of the hydrogenerator.
In view of above, an improved arrangement of ventilating spacers for
construction of air duct has been explored and invented to achieve the
satisfactory performance of hydrogenerator.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose an improved ventilating
space device for forming air ducts, which eliminates the disadvantages of prior
art.
Another object of the invention is to propose an improved ventilating space
device for forming air ducts, which reduces hydraulic losses including reduction
in churning loss.
A still another object of the invention is to propose an improved ventilating space
device for forming air ducts, which adapts a fan of optimum capacity to reduce
power consumption.
Yet another object of the invention is to propose an ventilating space device,
which is enabled to achieve the temperature of core and winding in accordance
with the designed parameters.
A further object of the invention is to propose an improved ventilating spacer
device, which is economically superior.
SUMARY OF THE INVENTION
Accordingly, an improved ventilating space device for hydrogenerators
comprising at least one leading edge spacer, a trailing edge spacer on tooth of
punching segment to configure ducts for flow of air, characterized in that the
leading edge spacer at entry point of air having an angle LA, and the trailing
edge spacer at entry point of air having an angle of LB, the angle LB being less
than LA, in that a distance (X) between the welding point of the leading edge
spacer and stator winding is smaller than that of the distance (Y) from the
welding point of the trailing edge spacer and stator winding, and in that a
distance (X1) between the leading edge spacer from the inner diameter is smaller
than a distance (Y1) between the trailing edge spacer and the inner diameter.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention can be described in detail with the help of the accompanying
drawings in which
Figure 1(A) Arrangement of ventilating spacer in prior art.
Figure 1(B) Arrangement of ventilating spacer in prior art (Section-AA).
Figure 1(C) Showing enlarge details of ventilating spacer on spacer punching
segment (Enlarge detail-X)
Figure 1(D) Showing entry of air at inner diameter (Enlarge detail-Z).
Figure 2 Showing a reverse flow in prior art arrangement of ventilating spacer.
Figure 3(A) Shows an improved ventilating spacer device according to the
invention.
Figure 3(B) Showing the details of the device of Figure 3(A) at entry point of air.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE
INVENTION :
As shown the Figures 3(A) and 3(B), the ventilating spacers (1,2) are spot
welded on to spacer punching segment (6).
According to the invention, the configuration of the spacers (1,2) at entry of air
has been changed completely with respect to prior design. A leading edge spacer
(1) has been machined at the entry point of air by providing an angle of (LA) to
guide air flow. Further, the leading edge spacer (1) is spot welded with a spacer
punching segment (6) having a lower distance (X) from the stator winding (3) as
compared to a distance (Y) of a trailing edge spacer (2) which has been
machined at an angle of (LB). The angle (LB) is kept less than (LA) . The
distance (XI) of the leading edge spacer (1) is kept lower from the inner
diameter as compared to the distance (YI) of the trailing edge spacer (2) from
the inner diameter. An additional joint spacer (7) is also spot welded at both
sides of the spacer punching segment (6)
Both the leading edge spacer and the trailing edge spacer (1,2) have been used
in a single length from the inner diameter to the outer diameter and spot welded
to the spacer punching segment (6) This invented device has resulted in saving
of material due to omitting at least one spacer (4) of prior art provided at back of
the winding (3) and further eliminates bends at various locations, see figure :
1(B) & 1(C).
The improved ventilating spacers device of the invention has resulted in following
advantages:-
1. The consumption of power has decreased due to reduction in hydraulic
losses but with substantial air flow through the ducts.
2. No reverse flow is noticed in any duct, hence achieving the designed
temperature of the core and winding.
3. Achieved high efficiency of the hydrogenerator due to reduction in
churning loss and power consumption by the fan.
4. There is cost reduction about 20% due to' reduction in material and
labour.
WE CLAIM :
1. An improved ventilating space device for hydrogenerators comprising at
least one leading edge spacer (1), a trailing .edge spacer (2) punching
segment (6) to configure ducts for flow of air, characterized in that the
leading edge spacer (1) at entry point of air having an angle LA, and the
trailing edge spacer (2) at entry point of air having an angle of LB, the
angle LB being less than LA, in that a distance (X) between the welding
point of the leading edge spacer (1) and stator winding (3) is smaller
than that of the distance (Y) from the welding point of the trailing edge
spacer (2) and stator winding (3), and in that a distance (Xi) between the
leading edge spacer (2) from the inner diameter is smaller than a
distance (Yi) between the trailing edge spacer (2) and the inner
diameter.
2. The device as claimed in claim 1, wherein the leading edge spacer (1) is
spot welded radially at various place on to spacer punching segment (6).
3. The device as claimed in claim 1, wherein the trailing edge spacer (2) is
spot welded radially at various place on to spacer punching segment (6).
4. The device as claimed in claim 1, wherein the joint spacer (7) is spot
welded at both sides of the spacer punching segment (6).
5. An improved ventilating space device for hydrogenerators as substantially
described and illustrated herein with reference to the accompanying
drawings.

The invention relates to an improved ventilating space device for
hydrogenerators comprising at least one leading edge spacer (1), a trailing edge
spacer (2) punching segment (6) to configure ducts for flow of air, characterized
in that the leading edge spacer (1) at entry point of air having an angle LA, and
the trailing edge spacer (2) at entry point of air having an angle of LB, the angle
LB being less than LA, in that a distance (X) between the welding point of the
leading edge spacer (1) and stator winding (3) is smaller than that of the
distance (Y) from the welding point of the trailing edge spacer (2) and stator
winding (3), and in that a distance (X1) between the leading edge spacer (2)
from the inner diameter is smaller than a distance (Y1) between the trailing edge
spacer (2) and the inner diameter.