Photo-Trol With Sensors
Photo-Trol Theory of operation:
When loop or material is in the zero speed position and both beams are broken the lower beam (stop/decel) should supply a N.C. contact and the upper beams(accel) should supply a N.O. contact. In this condition the motor will be at zero speed.
When loop or material raises and is in the run position lower beam will be exposed (contact will be open) and upper beam will still be broken (contact will still be open) motor will run at a determined base speed setting set by P3 on the Photo-Trol.
If line increases in speed and calls for a faster unwind speed, loop or material will raise and expose both beams (lower will be open & upper will now be closed) and the control will start to add voltage to the base speed setting increase motor speed. The amount of increase depends on setting of accel adjustment and how long upper beam is exposed.
When the upper beam is broken again the loop control will then hold the calculated line speed.
If at any time the bottom beam is broken voltage is subtracted from the calculated line speed.
The rate if subtraction is adjustable
If the beam is broken for long the speed will be decreased to zero and the line will stop.