Thyristor speed control unit

LD 73532
Thyristor speed control unit
Thyristor speed control unit


Compact static converter for setting and performing open and closed loop control of DC voltage and current. In addition to making a multitude of experiments possible, it can also be used to control the speed of a shunt wound machine from 0.1 kW to 2.6 kW with cascade current control in four-quadrant operation.

Technical data


  • Mains switch and delayed response main contactor for armature and exciter voltages
  • Separate fuses, which can be serviced externally, for excitation, the electronic components and three-phase current
  • Exciter voltage output: 220 V, 1 A
  • Thyristor power circuit with two fully controlled B6 bridges for
    circulating current-free four-quadrant operation, nominal data (UL1N = 90 V): 0...230 V, 12 A, Indication of the active static converter via 2 LEDs
  • Complete electrical isolation between power circuit and control and regulating unit
  • Extensive fault monitoring with signalling and switch-off. Activation for phase-failure, rotating field fault, machine or equipment overheating and time limit
  • Control and regulating electronics with extensive indication, setting and measuring possibilities
Controlling and regulating
  • Potentiometer for the setpoint encoder with changeover switch for single quadrant and four quadrant operation
  • Run-up integrator with potentiometer for the run-up time: 0.1...100 V/s
  • Speed controller with summing point:
    Two inverting input and one non-inverting input
  • Variable gain VN = 1...10 for actual speed value
  • Coarse and fine adjustment of the proportional action coefficient:
    KPN = 0.5...5/5...50
  • Coarse and fine adjustment of the reset time:
    TNN = 0.1 s...1 s/1 s...10 s
    I controller can be switched off
  • Overdrive indication via LED
  • Both converters I and II have a potentiometer for current limitation
    Imax I = 0...12 A
    Imax II = 0...12 A
  • Instantaneous comparator with adjustable hysteresis
  • Absolute-value generator with measurement socket for control signal INVert
  • Adaptive current controller with summing point:
    Two inverting inputs and one non-inverting input
    Recognition of intermittent current with LED display and measurement socket for the control signal STL (intermittent current)
    Reduction of the reset time to 1/10, when intermittent current is present, can be switched off
    Coarse and fine adjustment of the proportional action coefficient:
    KPI = 0.05...0.5/0.25...2.5
    Coarse and fine adjustment of the reset time:
    TNI = 10 ms...100 ms/100 ms...1 s
    I controller can be switched off
    Overdrive indication with LED
  • Control angle limiter with the following setting options: Rectifier stability limit 0°...80°
    Inverter stability limit 180°...100°
  • Switching logic with measurement sockets for the control signals and with a control input STOP

  • Four-quadrant indication with 4 LEDs

  • Current measurement with current converters
  • The control set provides six double-pulse trains which are switched through to the thyristors of the rectifiers I or II via 12 gate pulse transformers

Supply voltage

  • Control unit: 230 V, 50 Hz
  • Power circuit: via external three-phase transformer
    3 x 45/90 V, 50 Hz (735 32)

Scope of delivery

  • Mains lead with shockproof plug

Related Documents

PDF (Instruction Sheet) PDF (Instruction Sheet) [735 32] Thyristor speed control unit
Print page

Contact Us

Technical Service & Support:

Online Service Portal
Do you have any questions or suggestions regarding our devices, products, experiments, equipment sets or about our software? You need spare parts? FORM

Repair Service
You would like to register a repair? FORM

For European distributors, please visit: European distributors
Worldwide requests
Please contact us per email:

 Click here for our contact form and postal address.

Contact Us