Asynchronous-thyristor starters


Structure of АТПУ starter
АТПУ devices are designed to launch induction phase motors of mechanisms with large rotating masses, as well as to regulate their rotation frequency in the range of 100... 85% of the rated value.
The structural diagram of АТПУ is given below.
ВВ1 – High-voltage switch
М – Motor
КМ – Contactor
МПСУ – Microprocessor control system
РП – Rotor converter
In АТПУ devices a controlled rotor converter РП is based on single-operation thyristors. РП load contains a set of ballast resistors with by-passing thyristor keys. In powerful АТПУ devices thyristor keys are replaced with contactors when not frequent activation of a processing installation is required.
Motor acceleration is followed by a step change of parameters of rotor converter load on МПСУ commands according to the preset pace. The smooth change of motor rotation velocity (frequency) is reached changing the control angle of thyristors in the rotor converter РП at every step. Switching on the contactor КМ the motor M is transferred to operation from the power line.
АТПУ is equippedwith a dynamic braking device (not indicated in the figure) to implement the motor’s accelerated halt mode.
The structure of the low-energy version of АТПУ device for the consequent start of a group of wound-rotor induction motors has the following form:
ВВ1, ВВ2, ВВ3 – High-voltage switches
М1, М2, М3 – Motors
ШКН – Low-voltage switching cabinet
КМ – Contactor
АТПУ –  Asynchronous-thyristor starter
РП – Rotor converter
АТПУ device provides smoother adjustment of the motor rotation frequency compared to resistive-contactor circuits of control (over rotor stations). Energy saving does not exceed units of percent in fractions of loss power at rotor station operation.
The delivery package of devices of АТПУ series is defined when ordering equipment.