Three-phase thyristor controller from Powerstax

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Three-phase thyristor controller from PowerstaxPowerstax is introducing its DTC 352 Dual Control Channel Three Phase Thyristor Controller suitable for use in electro-chemical processes and control of motors, heaters and traction equipment.

The DTC 352 is a dual-channel three-phase thyristor controller allowing closed-loop control of both output voltage and current on either primary or secondary thyristors. Its robust control circuit allows it to operate from a range of AC power supplies including generators. The DTC 352 can be used either as an open-loop controller or as a two-channel closed-loop controller to control two parameters (feedback signals) simultaneously. For two-channel control, when one of the two feedback signals reaches its pre-set value, the DTC 352 will control to this feedback signal at the set value and it will self-adjust to compensate for any mains supply and load variation.

External ‘LOGIC CONTROL’ functions are available to start and stop the output current and voltage with automatic soft-start, minimising inrush current. The ‘LOGIC CONTROL’ also provides a system ‘inhibit’ to the thyristor trigger pulses. When the DTC 352 is first powered up (or started by the ‘‘LOGIC CONTROL”) with an input signal present, the output will gradually ramp up from zero to the pre-set level according to the pre-set period. The ‘‘LOGIC CONTROL” will inhibit the output to zero instantly when this is disabled.

Key features of the Powerstax DTC 352 Thyristor Controller include primary or secondary control available, auto-adjust for 50 or 60Hz supply frequency, “Logic Control” for ON and OFF, power on and “LOGIC” on soft-start with adjustable delay, wide selection of supply voltages and span and zero adjust for wide range of different inputs. The DTC 352 has an operating temperature range of 0 to 50degC and isolation of 2500Vrms between input and output. An auxiliary 10V output is provided for local (manual) control and LEDs provide indication of power on, “LOGIC CONTROL” status, phase loss and when either channel reaches its limit setting

The current control feature of the DTC352 provides inherent output current limiting allowing the output current to be limited to a pre-set safe level to protect the load from over current. This feature is recommended for use with high inrush current loads.

Powerstax products are designed to meet the harsh environmental conditions they are required to operate in, and high reliability is central to all Powerstax designs to ensure continuous operation and minimise disruptive and costly down-time.

Tim Worley, CEO of Powerstax, comments: “Powerstax continues to build on the vast experience at our disposal the needs of our very diverse applications base. Our new DTC 352 dual-channel three-phase thyristor controller provides a stand-alone control solution for a large number of high-power control systems.”

Powerstax manufactures transformer rectifiers with output currents to 5000A and output power up to 1000kVA and beyond. Products are available for harsh (marine, offshore, desert) and hazardous (Zone 1 and Zone 2) environments and can be oil, air or water cooled and can be sealed up to IP65 if the environment dictates, with purge and pressure systems and heat exchangers incorporated if required

The markets served by Powerstax include metal finishing, marine, offshore, cathodic protection, water treatment (electrochlorination), electrochemical and plating and engine starting, within high-end industrial, defence, vehicle and transportation, defence and avionics, communications, test, measurement and control and medical equipment. For more information visit or download the DTC 352 Dual Control Channel Three Phase Thyristor Controller datasheet from

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