PSC motor system for use in HVAC applications with field adjustment and fail-safe capabilities

1. A field adjustable motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals and in response to field adjustment signals, wherein the input control signals define a first and a second operating state of the controller, each of the first and second operating states corresponding to a desired operating state of the system;

a first field adjustment circuit for providing a first field adjustment signal to the controller, the first field adjustment signal, in combination with the input control signals, defining a desired output parameter of the inverter for the first operating state; and

a relay coupled at its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller and being configured such that, in the event of a failure of the controller, the relay will couple the line power to the motor.

2. The field adjustable motor control system of claim 1 wherein the first field adjustment circuit may be modified in the field to provide one or more potential first field adjustment signals.

3. A field-adjustable motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals and in response to field adjustment signals, wherein the input control signals define a first and second operating state of the controller, each of the first and second operating states corresponding to a desired operating state of the system;

a first field adjustment circuit for providing a first field adjustment signal to the controller, the first field adjustment signal, in combination with the input control signals, defining a desired output parameter of the inverter for the first operating state; and

a relay coupled at its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller and being configured such that, in the event of a failure of the controller, the relay will couple the line power to the motor, wherein:

the controller is a digital controller;

the controller is configured such that the first operating state is associated with a plurality of potential control set points for the inverter; and

the first field adjustment signal determines the particular control set point to which the inverter is controlled in response to the controller's receipt of input control signals corresponding to the first operating state.

4. The field adjustable motor control system of claim 3 where the plurality of control set points corresponds to desired output current levels.

5. A field-adjustable motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals and in response to field adjustment signals, wherein the input control signals define a first and a second operating state of the controller, each of the first and second operating states corresponding to a desired operating state of the system;

a first field adjustment circuit for providing a first field adjustment signal to the controller, the first field adjustment signal, in combination with the input control signals, defining a desired output parameter of the inverter for the first operating state;

a relay coupled as its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller and being configured such that, in the event of a failure of the controller, the relay will couple the line power to the motor; and

a second field adjustment circuit for providing a second field adjustment signal to the controller, the second field adjustment signal, in combination with the input control signals, defining a desired output parameter of the inverter for the second operating state;

wherein the controller is a digital controller;

wherein the controller is configured such that the first operating state is associated with a plurality of potential control set points for the inverter and the second operating state is associated with a plurality of potential control set points for the inverter;

wherein the first field adjustment signal determines the particular control set point to which the inverter is controlled in response to the controller's receipt of input control signals corresponding to the first operating state and the second field adjustment signal determines the particular control set point to which the inverter is controlled in response to the controller's receipt of input control signals corresponding to the second operating state; and

wherein there is at least some overlap of the potential set points associated with the first operating state and the potential set points associated with the second operating state.

6. A field-adjustable motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals and in response to field adjustment signals, wherein the input control signals define a first and a second operating state of the controller, each of the first and second operating states corresponding to a desired operating state of the system;

a first field adjustment circuit for providing a first field adjustment signal to the controller, the first field adjustment signal, in combination with the input control signals, defining a desired output parameter of the inverter for the first operating state; and

a relay coupled at its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller and being configured such that, in the event of a failure of the controller, the relay will couple the line power to the motor,

wherein the first field adjustment circuit may be modified in the field to provide one or more potential first field adjustment signals, and

wherein the field modification is accomplished by the positioning of one or more jumpers within the first field adjustment circuit.

7. A field-adjustable motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals and in response to field adjustment signals, wherein the input control signals define a first and a second operating state of the controller, each of the first and second operating states corresponding to a desired operating state of the system;

a first field adjustment circuit for providing a first field adjustment signal to the controller, the first field adjustment signal, in combination with the input control signals, defining a desired output parameter of the inverter for the first operating state; and

a relay coupled at its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller and being configured such that, in the event of a failure of the controller, the relay will couple the line power to the motor;

wherein the relay includes a coil and, when the relay coil is unenergized, the relay couples the motor to the source of line power.

8. A field-adjustable motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals and in response to field adjustment signals, wherein the input control signals define a first and a second operating state of the controller, each of the first and second operating states corresponding to a desired operating state of the system;

a first field adjustment circuit for providing a first field adjustment signal to the controller, the first field adjustment signal, in combination with the input control signals, defining a desired output parameter of the inverter for the first operating state; and

a relay coupled at its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller and being configured such that, in the event of a failure of the controller, the relay will couple the line power to the motor,

wherein, in response to the input control signals defining the first operating state, the controller controls the output of the inverter in accordance with a first volt vs. hertz relationship, and

wherein, in response to the input control signals defining the second operating state, the controller controls the output of the inverter in accordance with a second volt vs. hertz relationship, the first volts vs. hertz relationship being different than the second volts vs. hertz relationship.

9. A motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals to provide a level of output power to the motor, the desired level of output power being determined at least in part by the input control signals;

wherein the input control signals define a first and a second operating state of the controller, each of the first and second operating states corresponding to a desired operating state of the system;

a first field adjustment circuit for providing a first field adjustment signal to the controller, the first field adjustment signal, in combination with the input control signals, defining a desired output parameter of the inverter for the first operating state;

a generally L-shaped bracket assembly;

a lid element adapted to be coupled to the curved exterior of a blower housing, the generally L-shaped bracket assembly being hingedly coupled to the generally L-shaped bracket assembly; and

a control module containing circuit components for an inverter and an electronic controller, mounted to the generally L-shaped bracket assembly such that, when the L-shaped bracket assembly is in a first position wherein the L-shaped bracket assembly makes contact with the lid assembly, access to the control module is blocked by the bracket assembly, and when the L-shaped bracket assembly is swung open along the hinged connection access to the control module is enabled.

10. A fail-safe motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals and in response to field adjustment signals; and

a relay coupled at its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller and being configured such that, in the event of a failure of the controller, the relay will couple the line power to the motor.

11. A fail-safe motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals and in response to field adjustment signals; and

a relay coupled at its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller and being configured such that, in the event of a failure of the controller, the relay will couple the line power to the motor,

wherein the relay includes a coil and, when the relay coil is unenergized, the relay couples the motor to the source of line power.

12. A fail-safe motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter in response to received input control signals, the controller being configured such that it will not provide signals to control the inverter if the power to the controller is insufficient to ensure proper controller operation;

a relay coupled at its inputs to a source of line power and to the output of the inverter and at its output to the motor, the relay receiving control signals from the controller, wherein the relay includes a relay coil, and wherein the relay couples the output of the inverter to the motor when the relay coil is in an unenergized state; and

a switching element coupled between the relay coil and a source of power and receiving a control signal from the controller, the switching element and the relay coil being configured such that, in the absence of a control signal from the controller, the relay coil is energized and, when a control signal from the controller is provided to the switching element, the relay is unenergized.

13. A fail-safe motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a controller coupled to the inverter, the controller providing signals to control the output of the inverter; and

means coupled to the motor, the inverter, the controller, and line power for:

(a) coupling the motor to line power when the controller fails but line power is sufficient to drive the motor; and

(b) coupling the motor to the output of the inverter and not driving the inverter, such that no power is provided to the motor, when the controller fails and line power is inadequate to drive the motor.

14. A fail-safe motor control system comprising:

a motor;

an inverter coupled to provide energization to the motor;

a relay coupled at one input to a source of line power and at another input to the output of the inverter, the relay being coupled at its output to the motor and being set in a first state where line power is provided to the motor and a second state where the output of the inverter is provided to the motor; and

a controller coupled to the inverter and the relay, the controller receiving a signal corresponding to the current output of the inverter, the controller further providing signals to control the output of the inverter and the state of the relay, wherein the controller monitors the current from the inverter and, if during normal operation where current should be flowing to the motor, the controller detects that no current or current below a defined level is going to the motor, the controller provides signals to the place the relay in the first state.