Thyro-S — digital thyristor switch, 1/2/3 phases, 8–350 A, 230–500 V

Country: USA · Model: Thyro-S

Thyro-S is a digital thyristor switch for heating loads of 8–350 A on 230, 400 and 500 V networks, with no mechanical contacts. It replaces contactors where heaters switch often, in panels of electric furnaces, pipeline trace heating, extruders and IR dryers.

Phases: 1S — 1 phase; 2S — 3-phase load in 2-phase circuit without neutral; 3S — 3 phases
Rated current: 8–350 A
Rated voltage: 230–500 V (−57 %…+10 % or −15 %…+10 % depending on version)
Frequency: 47–63 Hz

Request a quote All specifications

Technical specifications

Phases	1S — 1 phase; 2S — 3-phase load in 2-phase circuit without neutral; 3S — 3 phases
Rated current	8–350 A
Rated voltage	230–500 V (−57 %…+10 % or −15 %…+10 % depending on version)
Frequency	47–63 Hz
Mode	on/off (TAKT), triggered by an external on/off controller or PLC
Load	resistive and transformer
Setpoint inputs	logic input 0–24 V DC (on > 3 V); system interface to fieldbus module
Load monitoring	threshold, relay (250 V, 6 A), analog output 0(2)–10 V / 0(4)–20 mA — H RLP3 version
Protection	built-in semiconductor fuse
Communication	micro-USB (Thyro-Tool Pro); BasicBusModule — PROFIBUS DPV1, PROFINET, EtherNet/IP, Modbus TCP, EtherCAT, CANopen (up to 8 units)
Mounting	DIN rail up to 60 A
Certificates	CE, UL 508 (8–350 A), CSA C22.2 No. 14

Specifications are taken from the manufacturer’s technical documentation. Updated 10/31/2026.

Description

The switch serves as the final element of on/off control, taking its command from an external temperature controller, PLC or host computer via a 0–24 V DC logic input or a fieldbus module. Loads may be resistive or transformer-fed, at 47–63 Hz. 1S connects between two phases or phase and neutral, 2S drives a three-phase load in the economical two-phase circuit without neutral, and 3S is fully three-phase. Version H RLP3 adds load monitoring with an adjustable threshold, a 250 V, 6 A alarm relay and an analog indication output, and LEDs show status and load percentage. A built-in semiconductor fuse protects the power section, and the control circuits are galvanically isolated. Setup runs over micro-USB in Thyro-Tool Pro, BasicBus puts up to 8 units on one bus, and the optional Thyro-Power Manager smooths peaks when many heaters switch on together.

How to choose

Pick the circuit (1S, 2S or 3S) first, then the rated current with a margin over the heater current. Mains tolerance depends on the version, −57 %…+10 % or −15 %…+10 %, so check it against the plant network. Since the switch only turns the load on and off, ROT phase-angle regulators (Soviet-era single-phase thyristor voltage regulators) are replaced with Thyro-A for 8–1500 A, Thyro-A+ for 16–650 A or Thyro-PX for 16–5000 A and up to 1000 V.

Request a price and lead time

Thyro-S — digital thyristor switch, 1/2/3 phases, 8–350 A, 230–500 V. We reply within one business day.

Or email office@usk.ua or call +38 (044) 339-50-20.

FAQ

How is the Thyro-S thyristor switch better than a contactor?

With no mechanical contacts, frequent switching causes no wear, sparking or burning. The 8–350 A range covers most furnace and dryer heaters.

How do I control Thyro-S from a PLC?

Apply the signal to the 0–24 V DC logic input, which switches on above 3 V. The other route is BasicBus with PROFINET, PROFIBUS DPV1, EtherNet/IP, Modbus TCP, EtherCAT or CANopen.

Can Thyro-S drive a three-phase heater without a neutral?

Yes, version 2S controls a three-phase load in a two-phase circuit without a neutral wire. Full three-phase control comes with 3S.

What certifications does Thyro-S have?

CE, UL 508 for units of 8–350 A and CSA C22.2 No. 14. Units up to 60 A mount on a DIN rail.