Question

A squirrel-cage induction motor having a rated slip of 1% on full load has a starting torque same as that of full load torque. The starting current is

• A. equal to full-load current
• B. 10 times the full-load current
• C. 8 times the full-load current
• D. 4 times the full-load current

Answer 1

The correct option is B 10 times the full-load current

$\frac{T_{st}}{T_{fl}}={\left(\frac{I_{st}}{I_{fl}}\right)}^2{s}_{fl}$

For, $T_{st}=T_{fl}$

$\frac{I_{st}}{I_{fl}}=\sqrt{\frac{1}{s_{fl}}}=\frac{1}{\sqrt{0.01}}=10$