Control Process

So called "sensorless control" of AC machines means having no mechanical (speed and/or position) sensors. However, usually this term only includes vector controlled drives, i.e. it does not comprise V/f open-loop control of Induction Motors (which is the simplest technique for driving an IM motor without a mechanical sensor).

For the induction mold, sensorless vector control is a mature technology, it has been around for a few decades. Almost all reputable drive manufacturers have ...

When a three phase induction motor has (1) delta connected stator windings for its normal running, and if (2) all the 6 terminals are brought out to the terminal box, than such stator windings can be connected temporarily in star formation also for the staring purpose. Such motors in star formation would draw 1/3 the staring current, compared to the starting current at delta formation. Once the motor reaches it’s near about the operating speed, the winding connection would be changed ba ...

The valve characteristic tends to linearize the response to a change in the process. For instance, if the gain if the process is linear, a 10% change can be made with a 10% valve trim movement, over the entire range of your process, then a linear trim valve will be easiest to tune, and can be made most responsive over the entire range.

If the gain of your process is non-linear, then a valve with trim cut to compensate for that non-linearity can give you a more stable process with ...

Using wireless to control processes or devices is still being evaluated. Just as with earlier technologies (PLC, for instance), the trust factor simply isn't there - this is human nature when dealing with new technologies. We have done several small installations, and I recently completed a POC at a WWTP that exceeded our expectations.

To the interference issue: most wireless technologies use spread spectrum or OFDM modulation techniques, which are highly resistant to RFI. We were ...