SSC JE Electrical Engineering 2014 Set 2 Solved Paper

In case of veries–
When motor are connected in series and are in running position, speed ∝ (Voltage)∝ (

V

2

) (i) (Since the voltage across each motor =

V

2

) and current is Ia .
Ns∝

V

2I

… (i)
In case of parallel– When the motor is connected in parallel and are in running position, speed ∝ (Voltage) (V). (Since voltage across each motor = V) and current is

la

2

Np∝

2V

d

… (ii)
From both the equation

Ns

Np

=

V 2I

2V I

N parallel = 4 N series.