Advanced proof-of-rotation switch

Patent · Tue Jun 29 00:00:00 EDT 1993

OSTI ID:6350241

Jones, R E; Snider, S D

Apparatus is described for controlling operations of a heating appliance employing, an electrically controlled gas valve supplying a gas to be combusted within the appliance, the appliance having an exhaust system for removing combustion products and including a motor driven exhaust fan, the apparatus comprising: means for sensing the rotational speed of the motor and for providing an output signal representative thereof, said motor operating over a range of rotational speeds; switch means for opening and closing the gas valve as a function of motor speed; and, first and second speed responsive means for determining when the motor is operating within a predetermined range of speeds, said first speed responsive means determining when the motor exceeds a first predetermined speed, said second speed responsive means determining when the motor exceeds a second predetermined speed, said first speed responsive means opening the gas valve when the motor speed is in a range between said first and second predetermined speeds, and operation of each of said first speed responsive means is controlled by said second speed responsive means, each speed responsive means comprising a monostable multivibrator and a flip-flop, the sensing means providing an input clock pulse to each monostable multivibrator the pulse width of which is a function of motor speed, and the monostable multivibrator providing a fixed pulse width trigger pulse to its associated flip-flop to set the flip-flop, the flip-flop being reset so long as the width of a trigger pulse is less than that of the clock pulse provided by the sensing means, but being set when the pulse width of the trigger pulse exceeds that of the clock pulse, setting of the flip-flop indicating the motor speed has reached a predetermined speed.

• Assignee: Emerson Electric Co., St. Louis, MO (United States)
• Patent Number(s): US 5222888; A
• Application Number: PPN: US 7-748287
• OSTI ID: 6350241
• Resource Relation: Patent File Date: 21 Aug 1991
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
03 NATURAL GAS
ELECTRIC CONTROLLERS
DESIGN
GAS FURNACES
BLOWERS
COMBUSTION PRODUCTS
DATA ACQUISITION
DATA ACQUISITION SYSTEMS
EXHAUST SYSTEMS
GAS APPLIANCES
MONITORS
MOTORS
ROTATION
SPEED REGULATORS
SWITCHES
VALVES
APPLIANCES
CONTROL EQUIPMENT
ELECTRICAL EQUIPMENT
ENGINES
EQUIPMENT
FLOW REGULATORS
FURNACES
MEASURING INSTRUMENTS
MOTION
320303* - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Equipment & Processes
034000 - Natural Gas- Combustion