Control and monitor for rotating arc welder

A method of monitoring the quality of welds produced by the rotating arc process comprising the steps, after initiation of the arc voltage and current, of;

• generating a voltage which represents the voltage fed to the said arc;
• generating a second voltage which represents the electric current passing through the said arc;
• multiplying by electronic means the voltages which represent the arc voltage and current to obtain a voltage which represents the instantaneous electrical power delivered to the work;
• feeding the last mentioned voltage to an electronic integrator so as to obtain a voltage which is the analog of the total electrical energy delivered to the arc;
• generating an analog voltage which is proportional to the length of time the said arc current is flowing;
• causing the said integrated electrical energy analog voltage to be divided by the said time analog voltage in an electronic divider;
• feeding the output of the said divider to a window comparator so as to compare said signal output with a pre-established range of signals;
• generating a signal as a result of said comparison which indicates whether the signal resulting from the said division is below, within the range of, or above pre-established limits for average electrical energy per unit of time;
• generating a voltage which represents the upsetting force between the parts being welded;
• generating a voltage which represents the relative displacement between the platens of the welding machine during the upset period;
• multiplying by electronic means the last mentioned voltages so as to obtain a product voltage which represents the instantaneous mechanical work done on the parts being welded;
• integrating by electrical means the last mentioned product voltage so as to obtain an analog voltage representing the total mechanical work performed on the parts being welded;
• dividing by electrical means the last mentioned analog voltage by the voltage representing the total motion of the platens with respect to each other to obtain a voltage representing average work per unit displacement of the said platens during said motion;
• comparing the voltage resulting from the last said division with a pre-established range of voltages;
• generating a signal as a result of said comparison which indicates whether the said average work is below, within, or above the range of pre-established limits;
• feeding the signals resulting from the aforesaid energy comparison and work comparison to a means which will develop a warning indication if either one of the last mentioned signals are not within their pre-established limits.

Apparatus for monitoring the quality of welds produced by the rotating arc welding process in parts which are upset and forged by the relative motion between a moving and stationary platen which support the parts on the welding machine, comprising;

• means for delivering a pre-determined electrical energy to the parts being welded;
• means for determining the total time for application of the said energy;
• means depending upon the aforesaid two means for generating a voltage which represents the average electrical energy delivered to the work over the said time;
• means for comparing the said voltage with a preset voltage range;
• means cooperating with said comparison means for indicating whether said voltage is below, within or above the said preset voltage range;
• additional means for generating a voltage which represents the upsetting force applied to the parts being welded;
• means for generating a voltage which represents the relative displacement between the platens of the welding machine during the upset period;
• means depending upon said last two mentioned means for generating a voltage that represents the average mechanical work per unit displacement applied to the parts during the said motion;
• means for comparing the last mentioned voltage which represents average mechanical work with a preset reference voltage range;
• means associated with the last said comparison means for indicating whether the last mentioned voltage is below, within or above the said second preset voltage range;
• and
• means for providing a warning signal if either of said voltages representing average energy per unit time and work per unit of displacement of said platens is not within its associated preset voltage range.