STARTING DEVICE WITH A PTC-RESISTOR FOR A SINGLE PHASE MOTOR

• US 3,593,081 A
• Filed: 09/19/1968
• Issued: 07/13/1971
• Est. Priority Date: 09/19/1968
• Status: Expired due to Term

• Current Assignee: Forst Sven
• Original Assignee: Forst Sven
• Inventors: FORST SVEN
• Application Number:
  US04/760,780
• Time in Patent Office: 1,027 Days
• US Class Current: 318/792
• CPC Class Codes: H02P 1/42 for starting an individual single-phase induction motor H02P27/04 takes precedence

Abstract

This invention relates to a single phase motor which includes in the circuit means thereof a starting winding in series with a PTC-resistor having lower and upper resistance ranges. The PTC resistor is designed so that it is only operable in the low resistance range when heated solely by the effects of the starting current flowing therethrough. External heating means is provided for supplying an amount of auxiliary heat to the PTCresistor to effect a shift to the high resistance range. The external heating means supplies heat at a rate which causes the shift to the higher resistance range to occur at a predetermined time.

Claims

1. A single phase motor includiNg circuit means, a branch of said circuit means having winding means for starting and a PTCresistor, said branch being connected to receive a starting current, said PTC-resistor having temperature dependent low and high resistance ranges and being designed to be operable in said low resistance range when heated solely by the effects of said starting current flowing therethrough, external heating means for supplying auxiliary heat to said PTC-resistor, and heat transfer curtailing means for initially curtailing the transfer of heat from said heating means to said resistor to effect a sudden shift to said high resistance range at a predetermined time.

2. A motor according to claim 1 wherein said external heating means supplies heat to said PTC-resistor continuously during the operation of said motor. 3. A motor according to claim 1 wherein said heat curtailing means is thermal insulation material between said heating means and said PTC resistor.