Stock Electronics has used triac technology for motor speed control for over 25 years. By committing to the development of increasingly sophisticated designs, it ensures highly stable and linear control characteristics have been achieved on an extensive range of fans tested and approved.  Careful selection of power and E.M.C filter components has ensured Stock Electronics controller are amongst the most reliable and E.M.C compliant available.

A recent development, in association with a local power electronics consultant, utilises high speed digital micro circuits known as P.I.C’s. 

What is a PIC?

A PIC (Programmable Interface Controller) is a microprocessor (a chip the size of a postage stamp!).  To determine what it will do in its end application, the PIC is programmed accordingly using computer software. A PIC without software can do nothing.

The Intel Pentium III is one type of micro processor found in computers.  These are programmed to perform many functions and are therefore much larger in size.  We are simply asking ours to control the speed of a fan.

The PIC replaces discrete components on the circuit board and can be re-programmed to provide custom designs.  Both these features enable us to build more complex designs and modify existing ones while keeping size and cost implications to a minimum.

How does it improve Triac speed control?

Some low specification examples of Triac motor speed controllers are fraught with problems with respect to EMC and audible noise.  They may fail to operate the Triac correctly, presenting the motor with unbalanced DC conditions and excessive harmonic currents.  These cause increased motor temperature, reduced motor life and the commonest customer complaint, ‘audible noise’.

Here’s how the PIC overcomes these problems:-

• It features multi pulse firing which eliminates non-latching or misfiring.  This feature is normally found only on more expensive controllers but, in this case, without the complexity and high component costs.

• An advanced digital compensation technique gives the unit an outstandingly low D.C level and stable control characteristic.

• Motor hum is also significantly reduced.