technical NOTES

S. N. Parameter MV Drive SPRS with GRR

7 Maintenance Very low or no mainte-

nance for the combination

of VFD + Sq. Cage Induction

Motors

High and periodic

maintenance is required

for GRR/SPRS + Slip

Ring induction Motors

due to presence of

slip rings, brushes &

resistance plate

8 Losses Marginally high with respect

to SPRS

9 Energy Saving Achieved in reduced speed

operation in the speed range of

10 to 100%

Energy saving achieved

with recovery of rotor

losses (6%0 to 95%

speed)

10 Foot Print Less More

11 Capex Slightly Higher Less

12 Reliability With advanced auto cell by

pass technology downtime less

With stand by option

of GRR operation in

case of SPRS failure.

2.3 Economic Analysis and Capital Investments

The cost benefit analysis is summarized including capital investment and annual
return on investment based upon net present value method.

S. N. Description Unit GRR

+SPRS

MV

Drive

Remarks

CAPITAL COST

1 Type of Motor to be used Type SRIM SCIM

2 Cost of squirrel cage induction

motor (11 KV) (SCIM )MOTOR

@1600/kw

Rs. Lac NA 51 SCIM motor

cost basis

3 Cost of Slip ring motor (SRIM) @

Rs1900 /kw

Rs. Lac 61 NA SRIM motor

cost

4 Cost of squirrel cage induction

motor (11KV Volt) @ Rs2250 /kw

Rs. Lac NA NA

5 Cost of MV Drive @3300/kw Rs. Lac NA 106 MV drive cost

basis

6 Cost of Slip recovery system

(SPRS) @ RS 1815/kw

Rs. Lac 59 NA SPRS cost

basis

7 Cost of GRR RS 600/Kw Rs. Lac 19 NA

8 MV capacitor bank(1540 KVAR) @

Rs 422/KVAR

Rs. Lac 6 Capacitor bank

cost added