公开(公告)号：US3593081A

公开(公告)日：1971-07-13

申请号：US3593081D

申请日：1968-09-19

Applicant: DANFOSS AS

Inventor： FORST SVEN

IPC: H02P1/42 ,  H02P1/44

CPC classification number: H02P1/42

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.

公开(公告)号：US3562587A

公开(公告)日：1971-02-09

申请号：US3562587D

申请日：1968-09-19

Applicant: DANFOSS AS

Inventor： FORST SVEN

IPC: H02H7/085 ,  H02K11/25 ,  H02H7/08 ,  H02H5/04

CPC classification number: H02H7/0852 ,  H02K11/25

Abstract: The invention relates to an overheating control device for an alternating current motor. The device comprises a symmetrical controlled semiconductor valve in the motor lead and PTC resistor means thermally coupled to the motor windings. The PTC resistor means is connected to the control electrode of the semiconductor valve and concomitant with a temperature rise in the motor windings, the current flowing through the PTC resistor means decreases to effect a closing of the semiconductor valve.