In single phase induction motors, during blocked rotor test, the rotor is:

Blocked Rotor Test: It is also known as the locked-rotor or short-circuit test.

This test is used to find:

• Short-circuit current with normal voltage applied to the stator
• Power factor on short-circuit
• Total leakage reactance X₀₁ of the motor is referred to as primary (i.e. stator) and the total resistance of the motor R₀₁ is referred to as primary.
   

Procedure:

• In this test, the rotor is locked (or allowed very slow rotation) and the rotor windings are short-circuited at slip-rings if the motor has a wound rotor.
• Just as in the case of a short-circuit test on a transformer, a reduced voltage (up to 15 or 20 percent of normal value) is applied to the stator terminals and is so adjusted that full-load current flows in the stator
• As in this case s = 1 (Motor rotor under rest), the equivalent circuit of the motor is exactly like a transformer, having a short-circuited secondary.
• The values of current, voltage, and power input on short-circuit are measured by the ammeter, voltmeter, and wattmeter connected in the circuits as before.
• Curves connecting the above quantities may also be drawn by taking two or three additional sets of readings at progressively reduced voltages of the stator.