Rotor Start with Resistors

SLIP RING MOTOR STARTER

ROTARY START WITH RESISTORS

This type of starting involves installing resistors in the motor's rotor circuit.

Unlike stator starters, the starting torque is proportional to the current drawn from the mains. The number of steps in the starter is determined by the maximum permissible transient starting current and the motor's characteristics.

Operation

• Pushbutton S1Q activates contactor K1M, and the motor starts running with all resistor groups connected to the rotor. Contactor K1M closes feedback contact 13-14, which in turn connects time-delay relay K1T.
• After a certain time, K1T/17-18 conducts the voltage to K11A. The stepped contactor K11A disconnects the starting step R1A and, via K11M/13-14, triggers the timer K2T.
• The above sequence is repeated K12A, K2T, K13A and K3T.
• The final step contactor is latched via K13A/13-14, disconnecting via K13A the step contactors K11A and K12A, as well as the timers K1T, K2T, and K3T. The final step contactor K13A short-circuits the rotor slip rings; the motor then rotates at its rated speed.
• As in most of the previous cases, the disconnection is effected by pressing the stop button S0Q or by the action of the protection device F2F.

Control apparatus

S0Q Stop: 01 1NC (A normally closed contact)

S1Q March: 10 1NA (One normally open contact)

K1M : 11 (1NA + 1NC)

K11A : 22 (2NA + 2NC)

K12A : 22 (2NA + 2NC)

K13A : 22 (2NA + 2NC)

K1T : 11 (1NA + 1NC)

K2T : 11 (1NA + 1NC)

K3T : 11 (1NA + 1NC)

F2F : 01 (1NC)

F3F: I according to the power of the coil K1M + K13A + K3T

Applications

• Load-start machines, soft-start machines.
• Cranes.
• Overhead cranes.
• Elevators.
• Lift.
• Paper printing machinery.
• Piston compressors.
• Volumetric pumps.
• Shears.
• Crushing machines, etc.