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The current draw of a pump driven by an electric motor, especially a centrifugal pump such as a heating-system circulating pump, is measured by detecting the voltage drop across a conductor segment connecting the power side and hence the power line to the motor control circuit. This eliminates the n

The current draw of a pump driven by an electric motor, especially a centrifugal pump such as a heating-system circulating pump, is measured by detecting the voltage drop across a conductor segment connecting the power side and hence the power line to the motor control circuit. This eliminates the need for a separate measurement resistor.

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1. A method of determining a current draw of a pump driven by an electric motor, and a motor control circuit being connected to said motor by a power line said method comprising the steps of:(a) measuring a voltage drop across at least a portion of a conductor having a definite resistance and connec

1. A method of determining a current draw of a pump driven by an electric motor, and a motor control circuit being connected to said motor by a power line said method comprising the steps of:(a) measuring a voltage drop across at least a portion of a conductor having a definite resistance and connecting said power line with said motor-control circuit; and(b) calculating said current draw from said voltage drop. 2. The method defined in claim 1 wherein said portion of said conductor having said resistance is a piece of current supply line connecting the power line with said motor-control circuit. 3. The method defined in claim 1 wherein the voltage drop is measured and the current draw is calculated from said voltage drop by a computing unit forming part of said motor-control circuit. 4. The method defined in claim 1 wherein a current measured in said portion of said conductor is converted into a current draw of said pump. 5. The method defined in claim 1 wherein in calculating said current draw from said voltage drop, a computer unit forming part of said motor control circuit compensates for a temperature of said portion of said conductor. 6. An electronically controlled pump assembly comprising:an electric motor having a power line connected thereto for energizing said electric motor;a motor control circuit connected to said motor and said power line for electronically controlling said pump assembly;a pump driven by said motor; andmeans for measuring a voltage drop across at least a portion of a conductor in the form of a wire segment having a definite resistance and connecting said power line with said motor control circuit and calculating said current draw from said voltage drop. 7. The assembly defined in claim 6 wherein said portion of said conductor is a piece of resistance wire with a known specific resistance and a defined length. 8. The assembly defined in claim 6 wherein said portion of said conductor is a bridge between a plug contact to which said power line is connected and a printed circuit board carrying said motor control circuit, said bridge having a defined resistance. 9. The assembly defined in claim 6 wherein said resistance is between 1 and 5 mΩ. 10. The assembly defined in claim 6, further comprising a processor forming part of said motor control circuit and constituting the means for measuring and calculating. 11. The assembly defined in claim 10 wherein said processor is provided to effect a regulatory action in response to the temperature of said portion of said conductor.