Apparatus and method for generating clock pulses from a power selsyn multiple motor drive system for a glassware forming machine

A method of generating a speed signal for a glassware forming machine including a plurality of driven mechanisms and a power selsyn multiple motor drive means, the selsyns having interconnected stator windings connected to a source of electrical power and having interconnected rotor windings for synchronously driving the driven mechanisms, the method of generating the speed signal having a frequency directly proportional to the speed of the selsyns comprising the steps of:

• (a) generating a first signal representing the frequency of the power signal present in the rotor windings;
• (b) generating a second signal representing the frequency of the power signal present in the stator windings;
• and
• (c) subtracting said first signal from said second signal to generate the speed signal as a difference frequency signal having a frequency which is equal to the difference between the stator and rotor power frequencies.

A method of generating clock signals for a glassware forming machine including a plurality of forming means for forming articles of glassware, a plurality of driven mechanisms, and a power selsyn multiple motor drive means for driving the driven mechanisms, the selsyns having interconnected stator windings connected to a source of three phase electrical power and having interconnected rotor windings for synchronously driving the driven mechanisms, and an electronic control means responsive to the clock signals for cyclically controlling the forming means in a timed predetermined sequence of steps for forming glassware, the method of generating the clock signals to the electronic control means comprising the steps of:

• (a) scaling each of the frequencies of the power signals by a predtermined amount;
• (b) defining each of said scaled power signals as a plurality of pulses;
• (c) comparing one of each of said plurality of power signal pulses with a preceding one of said same plurality of pulses to determine if either of the power signals has changed from low to high;
• (d) generating a change signal when only one of the power signals changes from low to high;
• (e) incrementing a count total in response to said change signal if the stator power signal changes from low to high and decrementing said count total in response to said change signal if the rotor power signal changes from low to high;
• (f) generating difference frequency signals to a timing pulse generator means in response to said count total;
• and
• (g) generating clock signals to the electronic control means in response to said difference frequency signals.