US 3,974,427 AGranted

Motor control apparatus for three position valve

AssigneeHoneywell Inc.

InventorKenneth G. Carson

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Abstract

A motor control apparatus having an electric motor which is driven in one direction by an alternating current power source and in a return direction by a spring return wherein a holding or braking of the motor is accomplished by the application of a source of direct current power to magnetize the motor and hold it in a predetermined intermediate position after the removal of the alternating current power source. The braking or holding action is removed by taking away the direct current power source and momentarily applying an alternating current power source to the motor to de-magnetize or degauss the motor so it is free to return to its initial condition under the power of the spring return. The motor control apparatus is particularly adapted for use to control a three position water valve supplying water to two different areas or zones as required by zone thermostats to have water supplied to one or the other of the zones or both of the zones depending upon the demand by the thermostats and the position of the motorized valve.

Claims7

Dependent claims

A motor control apparatus comprising:

an electric motor means havng output means, said motor means having the characteristic that its output means is held by residual magnetism of said motor means after the application and then removal of a direct current power source,
an alternating current power source,
circuit means connecting said alternating current power source to said motor means to energize said motor means in one direction to drive said output means to a position between an initial position and an end position,
spring return means connected to said motor means for driving said motor means in the other direction when said motor means is not being energized by said alternating current power source,
a source of direct current power,
circuit means for connecting said source of direct current power to said motor means to magnetize said motor means to brake said motor means and hold said output means in a predetermined position intermediate said initial and said end positions when said alternating current power source driving said motor means in said one direction is removed,
and further circuit means for temporarily energizing said motor means with alternating current power to demagnetize said motor means to remove any residual magnetism when said output means is to return toward said initial position under the power of said spring return means.

4 more elements

Dependencies are inferred from the claim text.