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Dual speed controller for attic ventilator

  • US 5,049,801 A
  • Filed: 03/09/1990
  • Issued: 09/17/1991
  • Est. Priority Date: 10/20/1982
  • Status: Expired due to Fees
First Claim
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1. A speed control circuit for applying electrical power from a power distribution circuit of the type having hot and return power conductors to a multiple speed induction motor of the type including an armature winding having a high speed power terminal, a low speed power terminal and a return power terminal, said controller circuit comprising, in combination:

  • a first-normally open thermostat having an unswitched power terminal, a switched power terminal and a temperature responsive switch element adapted to make a closed circuit between said switched and unswitched power terminals at a first temperature level;

    a second normally open thermostat having a switched power terminal, an unswitched power terminal and a temperature responsive switch element adapted to make a closed circuit between said switched and unswitched power terminals at a second temperature level;

    a single pole, double throw switch assembly, said switch assembly having an unswitched power terminal, normally closed and normally open power terminals and a movable switch element connected to said unswitched power terminal;

    a solenoid including a control winding having first and second power terminals and control linkage mechanically coupled to said movable switch element for moving said switch element from electrical contacting engagement with said normally closed power terminal to said normally open power terminal in response to the application of electrical power to said control winding;

    the switched power terminal of said first thermostat being adapted for connection to the low speed power terminal of said motor, the unswitched power terminal of said first thermostat being connected to the normally closed power terminal of said switch assembly, the switched power terminal of said second thermostat being electrically connected to the first power terminal of said solenoid control winding, the unswitched power terminal of said second thermostat being connected to the unswitched power terminal of said switch assembly, the second power terminal of said solenoid winding being adapted for connection to the return power terminal of said induction motor and to the return power conductor of said power source, the normally open power terminal of said switch assembly being adapted for connection to the high speed power terminal of said induction motor, and the unswitched power terminal of said switch assembly being adapted for electrical connection to the hot power conductor of said power source.

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