US3593081A - Starting device with a ptc-resistor for a single phase motor - Google Patents

Starting device with a ptc-resistor for a single phase motor Download PDF

Info

Publication number
US3593081A
US3593081A US3593081DA US3593081A US 3593081 A US3593081 A US 3593081A US 3593081D A US3593081D A US 3593081DA US 3593081 A US3593081 A US 3593081A
Authority
US
United States
Prior art keywords
resistor
ptc
means
heat
starting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Inventor
Sven Forst
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Danfoss AS
Original Assignee
Danfoss AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Danfoss AS filed Critical Danfoss AS
Priority to US76078068A priority Critical
Application granted granted Critical
Publication of US3593081A publication Critical patent/US3593081A/en
Anticipated expiration legal-status Critical
Application status is Expired - Lifetime legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02PCONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P1/00Arrangements for starting electric motors or dynamo-electric converters
    • H02P1/16Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
    • H02P1/42Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual single-phase induction motor

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.

Description

United States Patent [72] Inventor Svenl-"orst CostaMesa.Calll. 21 AppLNo. 760,780 221 Filed Sept.19,l968

[45] Patented July 13, 1971 [73] Assignee Danioss AIS Nordborg, Denmark [$4] STARTING DEVICE WITH A FTC-RESISTOR FOR A SINGLE PHASE MOTOR 3 Chims,2 Drawing Figs.

[52] US. 318/221 E,v

318/221 H, 318/229 [51] Int. "l 1102p 1/44 [50] Field of Search 318/220. 22 l 229 [56] References Cited FOREIGN PATENTS 1,042,126 9/1966 GreatBritaini Primary Examiner-Oris L. Rader Assistant Examiner-Gene Z. Rubinson Anorney-wayne B. Easton rate which;causes the shift to the higher resistance range to occur at a predetermined time.

THERMAL INSULATION HEATlNG RESISTOR PATENTEflJuualsn 3,593,081

THERMAL INSULATION 2 PTC RESISTOR hitherto located in a range of lower resistance, moves into a range of higher resistance beyond the peak of its current-voltage curve. Such design of the FTC-resistor causes difficulties, however, if fairly lengthy starting times, seconds, for example, have to be considered. In this case an inert PTC-resistor is required which, because of its greater dimensions, is thermally loaded in a nonuniform manner and easily cracks.

The object of the invention is to provide a starting device wherein the starting time can be selected independently of the size of the FTC-resistor, and which, in particular, is suitable for fairly lengthy starting periods.

According to the invention, this object is achieved by so dimensioning the FTC-resistor that, upon its being heated up by the starting current only, its operating point is still located .in front of the peak of its current-voltage curve, and by providing an additional heating device which shifts the operating point beyond the peak at the desired moment. In this arrangement a smaller FTC-resistor can be used which is heated up rapidly and uniformly by the current flow- 'ing therethrough and therefore does not run the risk of damage due to mechanical thermal stresses. It reaches its equilibrium temperature after a short timeand independently of the required starting period. The change-over" to the range of higher resistance only takes place with the help of the additional heating device. At a freely selectable point of time, this latter device supplies additional energy such that the increase in temperature necessary for surmounting the peak is supplied. Since the FTC-resistor, due to self-heating, can already have reached an operating point shortly in front of the peak, a very small difference in temperature suffices for this.

The precise point in time at which the additional heating device becomes operative can be fixed in a large number of ways. For example, the heating device can be supplied with a time-controlled heating impulse. The heating device can also be switched on when the motor is switched on, but can act upon the FTC-resistor by way of an action-delaying path. For instance, thermal insulation between the heating device and the FTC-'resistor can serve to provide the delayed action. lt is also possible, without difficulty, to design a heating resistor of such mass and inertia that the desired delayed action takes place.

In a further form of the invention, the additional heating device can remain continuously switched on while the motor I is operating. By this step it is ensured that in all circumstances the PTC-resistor retains a temperature in the high ohmic 'range even after the current passing therethrough has been reduced.

The invention will now be described in more detail by reference to an embodiment illustrated in the drawing, wherein:

FIG. I shows the current-voltage characteristic curve of a FTC-resistor having different operating points, and

intersection, of which, however, only points P1 in the lowohmic range and P in the high-ohmic range are stable,

whereas point P is not stable.

When the FTC-resistor is heated by the current flowing therethrough, the branch of the curve will run from the zero point to the operating point P,. The FTC-resistor thus remains in the low-ohmic range. This is in contrast to the known arrangements wherein the FTC-resistor was so designed that no stable operating point P, at all established itself; rather, the peak S of the curve I lay below the operating characteristic curve II.

By means of addiiional heating, the temperature of the FTC-resistor is so raised at the desired time, i.e. at the end of the starting period, that the operating point shifts beyond the peak S. As soon as this is achieved, the operating point automatically moves to P; in the high-ohmic range.

In the connecting diagram shown in FIG. 2, a single-phase motor 1 with a winding 2 for normal running and a starting winding 3 is connected via a switch 4 to the terminals 5 and 6 of an A.C. mains supply. A FTC-resistor 7 is connected in series with the starting winding. Connected in parallel with this arrangement is an additional heating resistor 8 which acts on the FTC-resistor 7 by way of a thermal insulation 9.

When the switch 4 is thrown, a large current first flows in the starting branch. This leads to rapid heating up of the PTC- resistor 7. A condition of equilibrium is established at a point P however, wherein the starting winding 3 is supplied with a sufficiently large starting current. From the outset, the heatin g resistor 8 is also heated by a constant current. It warms up gradually and, delayed by its mass and by the thermal insulation 9, gives off heat to the FTC-resistor 7. By correctly rating the elements 8 and 9, it is possible, without difficulty, to cause the additional heat to act upon the FTC-resistor only towards the end of the selected period, e.g. after 10 seconds, and in such a manner that the peak Scan be surmounted. At this moment, the PTC-resistor switches over to point P so that the starting current is reduced to a low value that causes no damage during continuous operation. The additional heating resistor 8 remains switched on during the entire running period of the motor and ensures that the temperature remains at a value necessary for keeping the current in the starting winding small. In particular, the starting current can be kept lower than would be possible without the resistor 8 being continuously switched in.

In many cases it also suffices if the heating resistor 8 is switched in for only a brief time, i.e. towards the end of the starting period. The heating resistor can also have a variable size, for example the current from the winding for normal running can flow through it, or a current which in turn flows through the FTC-resistor, this being achieved, for example, by the heating resistor being in parallel with the starting winding.

I claim:

I. A single phase motor including circuit means, a branch of said circuit means having winding means for starting and a FTC-resistor, said branch being connected to receive a starting current, said FTC-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 FTC-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.

Claims (2)

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.
US3593081D 1968-09-19 1968-09-19 Starting device with a ptc-resistor for a single phase motor Expired - Lifetime US3593081A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US76078068A true 1968-09-19 1968-09-19

Publications (1)

Publication Number Publication Date
US3593081A true US3593081A (en) 1971-07-13

Family

ID=25060172

Family Applications (1)

Application Number Title Priority Date Filing Date
US3593081D Expired - Lifetime US3593081A (en) 1968-09-19 1968-09-19 Starting device with a ptc-resistor for a single phase motor

Country Status (1)

Country Link
US (1) US3593081A (en)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3737752A (en) * 1971-04-09 1973-06-05 Texas Instruments Inc Motor control system
US3864605A (en) * 1972-12-29 1975-02-04 Siemens Ag Overload protection for miniature d-c motors
US5103153A (en) * 1988-11-02 1992-04-07 North American Philips Corporation Control equipment for multi-speed electric motors
US20050007062A1 (en) * 2003-07-09 2005-01-13 Mehlhorn William L. Switch assembly, electric machine having the switch assembly, and method of controlling the same
US9328727B2 (en) 2003-12-08 2016-05-03 Pentair Water Pool And Spa, Inc. Pump controller system and method
US9404500B2 (en) 2004-08-26 2016-08-02 Pentair Water Pool And Spa, Inc. Control algorithm of variable speed pumping system
US9551344B2 (en) 2004-08-26 2017-01-24 Pentair Water Pool And Spa, Inc. Anti-entrapment and anti-dead head function
US9556874B2 (en) 2009-06-09 2017-01-31 Pentair Flow Technologies, Llc Method of controlling a pump and motor
US9568005B2 (en) 2010-12-08 2017-02-14 Pentair Water Pool And Spa, Inc. Discharge vacuum relief valve for safety vacuum release system
US9726184B2 (en) 2008-10-06 2017-08-08 Pentair Water Pool And Spa, Inc. Safety vacuum release system
US9777733B2 (en) 2004-08-26 2017-10-03 Pentair Water Pool And Spa, Inc. Flow control
US9885360B2 (en) 2012-10-25 2018-02-06 Pentair Flow Technologies, Llc Battery backup sump pump systems and methods
US9932984B2 (en) 2004-08-26 2018-04-03 Pentair Water Pool And Spa, Inc. Pumping system with power optimization
US9979326B1 (en) * 2016-11-10 2018-05-22 Whirlpool S.A. Device, system and method for starting a single-phase induction motor
US10240606B2 (en) 2004-08-26 2019-03-26 Pentair Water Pool And Spa, Inc. Pumping system with two way communication
US10465676B2 (en) 2011-11-01 2019-11-05 Pentair Water Pool And Spa, Inc. Flow locking system and method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1042126A (en) * 1963-02-25 1966-09-14 Danfoss As Improvements in or relating to starting devices for single phase motors

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1042126A (en) * 1963-02-25 1966-09-14 Danfoss As Improvements in or relating to starting devices for single phase motors

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3737752A (en) * 1971-04-09 1973-06-05 Texas Instruments Inc Motor control system
US3864605A (en) * 1972-12-29 1975-02-04 Siemens Ag Overload protection for miniature d-c motors
US5103153A (en) * 1988-11-02 1992-04-07 North American Philips Corporation Control equipment for multi-speed electric motors
US7427844B2 (en) 2003-07-09 2008-09-23 A. O. Smith Corporation Switch assembly, electric machine having the switch assembly, and method of controlling the same
US20050007062A1 (en) * 2003-07-09 2005-01-13 Mehlhorn William L. Switch assembly, electric machine having the switch assembly, and method of controlling the same
US20050158177A1 (en) * 2003-07-09 2005-07-21 A.O. Smith Corporation Switch assembly, electric machine having the switch assembly, and method of controlling the same
US20050156557A1 (en) * 2003-07-09 2005-07-21 A. O. Smith Corporation Switch assembly, electric machine having the switch assembly, and method of controlling the same
US6989649B2 (en) 2003-07-09 2006-01-24 A. O. Smith Corporation Switch assembly, electric machine having the switch assembly, and method of controlling the same
US7042192B2 (en) 2003-07-09 2006-05-09 A.O. Smith Corporation Switch assembly, electric machine having the switch assembly, and method of controlling the same
US20070113647A1 (en) * 2003-07-09 2007-05-24 A.O. Smith Corporation Switch assembly, electric machine having the switch assembly, and method of controlling the same
US7183741B2 (en) 2003-07-09 2007-02-27 A. O. Smith Corporation Switch assembly, electric machine having the switch assembly, and method of controlling the same
US9328727B2 (en) 2003-12-08 2016-05-03 Pentair Water Pool And Spa, Inc. Pump controller system and method
US9371829B2 (en) 2003-12-08 2016-06-21 Pentair Water Pool And Spa, Inc. Pump controller system and method
US9399992B2 (en) 2003-12-08 2016-07-26 Pentair Water Pool And Spa, Inc. Pump controller system and method
US10409299B2 (en) 2003-12-08 2019-09-10 Pentair Water Pool And Spa, Inc. Pump controller system and method
US10241524B2 (en) 2003-12-08 2019-03-26 Pentair Water Pool And Spa, Inc. Pump controller system and method
US10416690B2 (en) 2003-12-08 2019-09-17 Pentair Water Pool And Spa, Inc. Pump controller system and method
US10289129B2 (en) 2003-12-08 2019-05-14 Pentair Water Pool And Spa, Inc. Pump controller system and method
US9605680B2 (en) 2004-08-26 2017-03-28 Pentair Water Pool And Spa, Inc. Control algorithm of variable speed pumping system
US10480516B2 (en) 2004-08-26 2019-11-19 Pentair Water Pool And Spa, Inc. Anti-entrapment and anti-deadhead function
US9777733B2 (en) 2004-08-26 2017-10-03 Pentair Water Pool And Spa, Inc. Flow control
US10415569B2 (en) 2004-08-26 2019-09-17 Pentair Water Pool And Spa, Inc. Flow control
US9932984B2 (en) 2004-08-26 2018-04-03 Pentair Water Pool And Spa, Inc. Pumping system with power optimization
US10502203B2 (en) 2004-08-26 2019-12-10 Pentair Water Pool And Spa, Inc. Speed control
US10240606B2 (en) 2004-08-26 2019-03-26 Pentair Water Pool And Spa, Inc. Pumping system with two way communication
US9551344B2 (en) 2004-08-26 2017-01-24 Pentair Water Pool And Spa, Inc. Anti-entrapment and anti-dead head function
US10240604B2 (en) 2004-08-26 2019-03-26 Pentair Water Pool And Spa, Inc. Pumping system with housing and user interface
US9404500B2 (en) 2004-08-26 2016-08-02 Pentair Water Pool And Spa, Inc. Control algorithm of variable speed pumping system
US10527042B2 (en) 2004-08-26 2020-01-07 Pentair Water Pool And Spa, Inc. Speed control
US9726184B2 (en) 2008-10-06 2017-08-08 Pentair Water Pool And Spa, Inc. Safety vacuum release system
US9556874B2 (en) 2009-06-09 2017-01-31 Pentair Flow Technologies, Llc Method of controlling a pump and motor
US9568005B2 (en) 2010-12-08 2017-02-14 Pentair Water Pool And Spa, Inc. Discharge vacuum relief valve for safety vacuum release system
US10465676B2 (en) 2011-11-01 2019-11-05 Pentair Water Pool And Spa, Inc. Flow locking system and method
US9885360B2 (en) 2012-10-25 2018-02-06 Pentair Flow Technologies, Llc Battery backup sump pump systems and methods
US9979326B1 (en) * 2016-11-10 2018-05-22 Whirlpool S.A. Device, system and method for starting a single-phase induction motor

Similar Documents

Publication Publication Date Title
US3569656A (en) Automatic cooking cycle control system for microwave ovens
US3612165A (en) Temperature controllers
US3893055A (en) High gain relays and systems
US4307327A (en) Control arrangement for single phase AC systems
US5455887A (en) Coffee-maker
US4214148A (en) Indicator for the extent of clarification of waterheaters in electric household appliances
US3612500A (en) Dryer control circuit
US4511789A (en) Heating element, particularly radiant heating element for heating glass ceramic plates
US4108713A (en) Low mass electric heater
US3311303A (en) Programmer
US4243875A (en) Temperature control for resistance heating element
US3646577A (en) Temperature-controlled soldering tool
US4841127A (en) Dual temperature hair curler utilizing a pair of PTC heaters
US3768545A (en) Temperature control system with multiple thermostats
KR900002781B1 (en) Heating appliance with uniform heating control
US3760310A (en) Thermoferrite switch with ptc resistor temperature compensation
US4871901A (en) Control device for a coffee roaster
US3364338A (en) Oven temperature control
US5053908A (en) Psc motor start system
US4024427A (en) Degaussing circuit
CA2505309C (en) Electronic thermostat for liquid heating apparatus
US3426441A (en) Electric hair dryer
GB1600089A (en) Control instrument for electric cooker plates
US3584196A (en) Automatic electric cooking appliance
US2444210A (en) Electronic timer