Abstract: In an AC motor having a main winding connectable to an AC power source for supplying running torque, and having a start winding connectable to the AC power source for supplying starting torque, a start switch is provided for connecting and disconnecting the start winding from the AC power source in starting and running modes, respectively. A main winding voltage phase detector detects the phase of voltage across the main winding. A start winding current phase detector detects the phase of current through the start winding during the starting mode. A cut-out circuit responds to the main winding voltage phase detector and to the start winding current phase detector.

Abstract: In an electric motor brake, a friction disc includes an anti-rattle portion integrally molded therewith and reducing the tolerance gap between the motor shaft hub and the friction disc to minimize rattling of the friction disc during rotation of the shaft, and eliminating the need for a separate anti-rattle spring. In a first embodiment, the friction disc has a cavity at the inner circumference thereof facing the hub, and a cantilever finger extending into the cavity and engaging the hub and providing a cantilever bias urging engagement of the hub and friction disc. In a second embodiment, a bump on a slotted inner circumference of the friction disc provides the biasing portion, or may be spaced from the hub by a nominal clearance.

Abstract: A proving switch is provided for an electromagnetic device for brakes and clutches having an energization coil energizable to attract an armature to a magnet body, the coil exhibiting increasing current flow therethrough upon application of an energization voltage thereacross, and exhibiting a momentary dip upon engagement of the armature and magnet body. Detection circuitry senses the current dip and provides a status signal in response thereto, confirming the engagement.

Abstract: A control circuit (10) is provided for an electric motor brake (12) having an electromagnetic brake coil (14) energizable to actuate the brake to a released condition permitting rotation of an electric motor (16), and de-energizable to enable actuation of the brake setting the brake to a braking condition stopping rotation of the motor. The control circuit includes a switch (102) having an on state energizing the brake coil, and an off state de-energizing the brake coil.

Abstract: A multi-level motor load sensing circuit senses first, second and third ranges of auxiliary winding voltage and provides a load-too-high signal for the first range, a load-OK signal for the second range, and a load-too-low signal for the third range, and provides an output which transitions from the load-too-high signal to the load-OK signal to the load-too-low signal as auxiliary winding voltage increases from the first range to the second range to the third range, and which transitions from the load-too-low signal to the load-OK signal to the load-too-high signal as auxiliary winding voltage decreases from the third range to the second to the first range. The output transitions twice during each of rising and falling values of auxiliary winding voltage between the first and third ranges. Hysteresis with improved tracking is also provided.

Abstract: A capacitor-start capacitor-run single phase AC induction motor control starting circuit is provided which minimizes first cycle current spiking magnitude, and also minimizes cycle to cycle current spiking magnitude, without a choke or inductor in the loop containing the run capacitor, start capacitor and start switch. The first cycle current spiking problem is solved by controlling when the start switch may be turned on at initiation of the starting mode in relation to the AC cycle, to permit turn-on of the start switch only within a known or predictable range of voltage differential between the run and start capacitors. The cycle to cycle current spiking problem is solved by proper phasing of gate current, and supplying gate current to the start switch in phase with the voltage across the run capacitor and out of phase with the current through the series connected start switch and start capacitor.

Abstract: A motor starting circuit (10) is provided for disconnecting the start winding (14) of a single phase AC induction motor from an AC source (18) after a time delay. A start switch (22) in series with the start winding (14) controls energization and disconnection of the start winding (14). Turn-on of the start switch (22) is controlled by a turn-on switch 28 connected in parallel across the start switch (22) and not across the start winding (14). Turn-off of the start switch (22) is controlled by a cut-out switch (50) which in turn is controlled by an RC timing circuit (58, 60) connected across the AC source (14). A restart switch (64) may be added without changing the remaining circuitry. The restart switch (64) controls charging of the timing capacitor (60) and causes reconnection of the start winding (14) to the AC source (18) when motor speed drops below a given cut-in speed.

Abstract: Low cost, low part content motor control circuitry is provided, including blanking interval circuitry (42, 25) for preventing immediate connection of the start capacitor (5) of a single phase AC induction motor to the AC source (4) upon energization of the motor, to protect the start capacitor (5) and the start switch (6) against an overcurrent condition if the motor is de-energized while in the running mode and then re-energized while still coasting above a given speed, and to particularly prevent burn-out of the start capacitor (5) and/or start switch (6) upon reapplication of electrical power after a momentary power outage. Differently sized capacitors (42, 24) provide an early cross-over of auxiliary winding voltage relative to main winding voltage at the input of a quad comparator chip (31-34) to disable a turn-on signal for the start switch (6).

Abstract: Blanking interval circuitry (106, 108, 110, 104) is disclosed for preventing immediate connection of the start capacitor (5) of an AC motor to the AC source (4) upon energization of the motor, to protect the motor against an overcurrent condition if the motor is de-energized while in the running mode and then re-energized while still coasting above a given speed, and to particularly prevent burn out of the start capacitor (5) and/or start switch (10) upon reapplication of electrical power after a momentary power outage. The start capacitor (5) is disconnected from the AC source (4) during a time delay blanking interval regardless of whether auxiliary winding voltage is above or below a given cut-in value relative to main winding voltage as a function of motor speed corresponding to a given cut-in speed.

Abstract: A low cost, low part content single phase AC induction motor control starting circuit is provided which is speed sensitive, load sensitive and AC line voltage fluctuation insensitive. A quad comparator chip (61-64) senses and compares relative magnitudes of main and auxiliary winding voltages (30, 32 and 42) to de-energize the auxiliary winding (2) at cut-out speed, and automatically re-energize the auxiliary winding (2) at cut-in speed to accelerate or restart the motor from a stall or overload condition. Simplified power supply and voltage detection circuitry is also disclosed.