Claims
- 1. An assembly for a refrigerator icemaker comprising:
- (a) an electromagnetic water valve having an encapsulated coil, said coil having a plurality of turns of relatively fine wire having the size chosen such that upon flow of normal operating current therethrough a desired magnetomotive force is produced and upon flow of said normal operating current in excess of a predetermined time, said coil begins heating and undergoes successive shorting of windings thereby decreasing the electrical resistance of said coil and increasing current flow therein, said coil operative upon said decreasing resistance to have drecreased magnetomotive force for deactuating said water valve.
- (b) heater means electrically series connected with said coil and adapted for heating ice for removal from a tray, said heater means having a resistance sufficient to act as a current limiter to prevent coil burnout and to permit current greater than normal to continue to flow despite said shorting; and
- (c) circuit protective means series connected to resistance decreasing to a predetermined level for terminating current flow through said heater means.
- 2. The assembly defined in claim 1 wherein said heater means has a greater impedance than said coil.
- 3. A control system for a refrigerator icemaker comprising:
- (a) an encapsulated coil operative upon flow of a normal operating current to provide a predetermined magnetomotive force and adapted for actuation of an electromagnetically actuated valve for controlling icemaker waterfill, said coil defining an armature receiving cavity and having a plurality of turns of relatively fine wire chosen such that the turns increase in temperature and successively short out in the event said normal operating current continues to flow for a time greater than a predetermined normal waterfill cycle time, said shorted coils thereupon operative to decrease the resistance of said coil and the magnetomotive force below said predetermined level and operative to permit current greater than a normal operating current to flow therethrough;
- (b) heater means electrically series connected with said coil and operative to perform an ice melting function upon flow of said normal operating current therethrough, said heater means having a resistance sufficient to act as a current limiter for said coil, which upon shorting continues flow of greater than normal current and is prevented from overheating and acting as a fuse;
- (c) current terminating means electrically series connected with said heater means, said terminating means operative to create an open circuit only when a predetermined limit current above said normal operating current flows in said heater means; and,
- (d) controller means, operative to effect switching of current to said coil for normal icemaker waterfill.
Parent Case Info
This application is a continuation of application Ser. No. 22,557, filed Mar. 6, 1987 which is now U.S. Pat. No. 4,791,523 issued Dec. 13, 1988 which is a continuation of Ser. No. 736,222 filed May 20, 1985, now abandoned.
US Referenced Citations (2)
Continuations (2)
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Number |
Date |
Country |
Parent |
22557 |
Mar 1987 |
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Parent |
736222 |
May 1985 |
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