technical NOTES

S. N. Description Unit GRR

+SPRS

MV

Drive

Remarks

9 Additional cost due to AC

arrangement

Rs. Lac 7

10 Additional Rotor Cable cost 3.3Kv

HT 300 Sq. mm cable @700 Rs/

Mtr (1000 Mtr 12 Runs)

Rs Lac 7

11 Capital Investment Rs. Lac 153 164

12 Investment Difference SPRS with

MV drive

11

Loss Calculation

1. Avg. Power Loss across SPRS
   @80% speed (Motor Power
   1536kw/1000 rpm)
   Overall efficiency/loss of SPRS
   solution: Transformer 98.5% *SPRS
   97% of 307KW (i.e. 20 % 1536 KW)
   
   
   • slip ring Motor 94.2% of 1536 KW
     Transformer and SPRS have 20%
     rating of Slip ring motor
     So total loss in SPRS and Trans-
     former =
   
   
   
   

NA

98.5%*97%*307MW (i.e. 20 % of

1536KW) = 13.68KW

Loss in Slip ring motor =

94.2%*1536MW = 89.09 KW

Total loss in SPRS solution(a+b) =

13.68+ 89.08= 102.77 KW = 103KW

103

Avg. Power Loss across MV Drive

@80% speed (Motor Power

1536Kw/1000 rpm/11KV)

Overall efficiency of MVD

solution:

Transformer 98.5% *MVD 98%

*Induction Motor 95.5% = 92.19%

Total loss in MVD solution = 1536

KW* 92.19% = 120 KW

KW NA 120

2 Difference in losses in SPRS and MV drive @ 80% speed KW 17

Fan operating

losses from

40 to 60 % &

95 % to 100%

speed through

GRR is more as

compared to

MV drives