Abstract: An animal containment system comprising a stationary transmitter including a transmitter for defining a first curtain of energy having a first code to be entered by an animal approaching an off limits area and a second curtain of energy adjacent the first curtain and having a second code, the second curtain to be entered after the animal passes through the first curtain approaching the off limits area, and at least one receiver to be carried by an animal to be contained including a receiver responsive to the first code when the animal is within the first curtain for issuing a warning signal and responsive to the second code when the animal is within the Second curtain for issuing a discipline signal.

Abstract: Apparatus for the prevention of undesirable and possibly hazardous automatic application of power to a load in the event of an outage from a power source and a subsequent re-application of power therefrom. Described is a thyristor type of circuit interrupter coupled into a control circuit which is operative to control the operation of phase-controlled SCR circuit which is cyclically operative to couple power from an AC power source to a load device such as a DC motor. In the preferred embodiment, an SCR circuit interrupter is coupled into the DC supply circuit of a control circuit comprising, inter alia, a pulse generator which provides trigger pulses which are applied to a pair of silicon controlled rectifiers in the phase-controlled SCR circuit.A two-pole, two-position switch is adapted in one (STOP) position to couple the AC power source to the SCR circuit interrupter which includes means for being latched, i.e.

Abstract: An improved motor control system in which cooperative interaction of a simplified programmed IR compensation structure and economical thermally compensated speed reference-error comparator combination result in an improved polluted power notch-immune synchronizing performance achieved with economy of components and incidental heating.