Generator construction.

1. Generator Construction
Presented By:
Anuj Kumar
Manager ( EMD)
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2. General Overview of Generator
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3. 3

4. Stator
frame
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 Stator frame is of special
pressure- proof design
that can withstand
pressure of 10Bar-
g,twice the maximum
gas pressure , 5.0Bar-g.
 The material used :
No.1 SM400 AP, of JIS
G 3106 rolled steel for
welded construction or
its equivalent.

5. Coil End & Overhang Part of Stator 5

6. 6

7. Lead box and Bushing
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 At the lower part of
the turbine side of
the stator frame lead
box is provided,
which has six lead
bushing, three on
the line side and
three on the neutral
side.
 The lead bushing is
also provided with a
gas passage for
inner cooling of lead
bushing.
 To eliminate stray
load loss and
overheating,
nonmagnetic steel is
used for the lead.

8. Lead Box and CT Connection 8
Phase CT
Neutral CT
Lead Box

9. Generator Rotor and Coil 9
 Shaft material solid forging of Ni-Cr-Mo-V steel is used. This is equivalent to the
requirements of the seven items for the shaft material standard of the ASTM Turbine
generator.

10. Exciter Slip –Ring and Brush gear Assembly
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 The slip ring is made of
tool steel and its slide
surface is spirally
grooved so as to ensure
a uniform contact of the
brush with slip ring.
 The groove also help the
air to escape so that the
high air pressure
generated on the ring
surface due to its
revolution at high speed
do not prevent the good
contact between the
brush and the ring.

11. VENTILATION OF GENERATOR
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12. COOLING SYSTEM (STATOR &
ROTOR) 12

13. ROTOR COIL END VENTILATION 13
 A blower on the
exciter side pushes
the gas that enters
the circular space
formed by the end
cover of the coil
retaining ring and
the shaft .
 The Gas moves In
the peripheral
direction along the
curved part of the
coil end. It is
discharged again
into the lower side
from the hole in the
center of the end
part

14. COOLING SYSTEM COMPARISON 14

15. Blower
 At NPL water-cooled
machine, a multi-stage
axial blower is installed
only at the exciter side.
In order to feed cooling
gas (Cold gas) in to a
long and narrow vent
duct in the axial direction
ventilation,.
 Both the stator blade
and rotor blade are
made of Ni-Co-Mo steel
and 13Cr steel of
precise casting
 Blades are fixed to the
blower shroud and hub
with dovetails
separately.
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16. Temperature Rise
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17. H2 Cooler
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 Two gas coolers are
arranged vertically both
right and left portion at
the exciter side of the
generator. Cooling tubes
with spiral fins are used .
 Material for the cooling
tube themselves ranges
from two to four kinds of
seamless copper alloy
tubes for condenser.

18. Allowable Load with Gas Cooler
Out Condition 18

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Thankyou