PR3-DIN-12kW

The PR3-DIN range of thyristor stacks provides full seamless control of three phase electric heating loads from a BMS or similar controller.  These burst firing controllers use zero volts switching technology, to minimise RFI problems. A 12kW or 18kW model is available for a typical ac voltage supply of 415V using the two-thirds control technique.  Both models have the same features that include:- DIN rail mounting capability; dc voltage signal control;  temperature trip with automatic reset, alarm output and LED ‘OUTPUT-ON’ indication;  easy access to internal signal & power terminals; no additional heatsink is required for each power rating.

APPLICATIONS

Suitable applications include electric heating coils, heating cables and electric furnaces.

FUNCTIONS

Cycle Time and Signal Rescaling

The cycle time is preset.  A 0 to 10V DC input signal of 5V equates to the load being at 50%  ON and likewise with a load of 2.5V the load will be 25% ON. A 10v input signal will therefore equal 100% i.e. fully ON.

CAUTION: Adjustment of the cycle time and signal rescaling is possible using HD3, HD4, VR1 and VR2 but is not normally required.  Incorrect settings of these controls can cause an overload condition, failure and permanent PR3-DIN –series damage.

DO NOT ATTEMPT TO ADJUST THESE CONTROLS WITHOUT REFERENCE TO THE SUPPLIER/MANUFACTURER.

Manual Override

The PR3-DIN series are supplied preset to the auto ‘A’ position.  It is possible to manually override the input signal by placing the HD2 jumper plug in the ‘M’ position.  With the jumper in the ‘M’ position the load will be 100{a984a5830547d01f8339f3e7c868b263ba707802b82f956d42d49dcda1c607d4} ON. The output load can be adjusted downwards using the signal rescaling facility (see above section).

 Over Temperature Protection

An electronic thermal cut-out is fitted to the heatsink to protect against over temperature. The PR3-DIN series will switch off the load if the heatsink temperature exceeds 90ºC and will reconnect to the load once the heatsink temperature has dropped below 85ºC. Under normal operating conditions the heatsink temperature will not reach 90ºC but this might occur, for example when the ambient temperature exceeds 40ºC.

Alarm Output

The alarm OUTPUT is referenced to 0V and the alarm terminal input.  The alarm is triggered by zero voltage present (as specifications).